Ya Like Dags?

Selling Out

2010-07-14T20:28:00.002-04:00

So you'll recall from the earlier post today that I've entered Ya Like Dags? into the next phase of its development. I'd like to announce that I am now part of the nascent Southern Fried Science network. I'll be keeping the blogspot address active just in case (mainly so people can see this post and then update their links accordingly) but I'm looking forward to the greater design flexibility, readership, and support involved in being part of a larger network (though not too large). So yes, you can think of it as selling out, but selling out to an indie label.

The blog can now be seen at www.yalikedags.southernfriedscience.com. The layout is very basic right now but I'll be tweaking it as I go. Thanks for your continued support and readership, and don't be shy in the comments.

AES Conclusions and An Announcement

2010-07-14T14:11:00.000-04:00

Below the jump you'll find a talk that I somehow managed to forget to discuss here on the blog, some parting remarks about the conference, and an announcement.

-I was totally remiss in forgetting to talk about Jason Link's talk on An Ocean Without Dogfish. This is especially egregious since his work has informed a lot of mine and that his findings on the ecological role of Squalus acanthias are directly applicable to my stuff. Basically Link knocked spiny dogfish completely out of the ecosystem using four different modeling programs. The general opinion is that the absence or reduction of dogfish will be beneficial for those commercially-important species that they potentially compete with. Obviously this is a very popular view with commercial fishermen. However, two of the four models showed no significant change in the numbers of those species in the absence of dogfish, one showed skates skyrocketing and suppressing even more species than the dogfish, and one showed only river herrings having a modest increase in population. In none of the models did commercially-important groundfish significantly increase in population. I generally am a bit skeptical of anything that is 100% modeling, but Link has access to a massive trophic database on the Northern Atlantic and has proven himself to be an expert on this ecosystem. Interesting stuff, and kind of antithetical to some of the more alarmist data points brought up by Sulikowski earlier in the conference.

-Overall, AES was a blast. I did a lot of networking, got some great feedback, and learned firsthand just what a fun-loving group shark people are. I will definitely be attempting to go next year when the conference hits Minneapolis (too bad it's not in the fall so I could check out a Vikings game while I'm there). Also, it was great to get back to the motherland of Rhode Island. I was pleasantly surprised to see that a lot of my favorite places are still doing alright (Lil' Rhody is second only to Michigan in being whacked by the economic downturn, something I will talk your ear off about over beers) and that newcomers to the state seem to enjoy it just as much as I do. The Westin was a pretty sweet hotel, though afflicted by the "nice hotel" tendency to charge you for everything possible. That said, the people working there were among the nicest I've had to deal with in a hotel situation. Overall a great experience that made me proud to call myself a shark person.

-One final announcement to for this post. I've been approached by representatives from a burgeoning mini-empire of salty bloggers, and will be joining their ranks. When I do, I'll put up a post here with the new address and try to make the move as quick and painless for you, the reader, as possible. This blog has been doing much better than expected thanks to you, the reader, and hopefully you'll be sticking around as it enters the next stage of its development.

AES Day 3.5

2010-07-11T11:58:00.000-04:00

Day 3 of the AES conference was the big feeding symposium, and there was plenty to sink my teeth into (all puns always intended). Today is mostly made up of the stress symposium, which is a little technical for my tastes but still interesting and an important topic. As you saw yesterday, I decided to choose my social life over blogging, something the Hot Girlfriend and my friends who came into town to visit probably appreciate. On to the good parts...

-One of the big trends in shark research has been the use of stable isotopes to determine diet and trophic level. This is viewed as a viable, minimally invasive way of getting at the overall place in the food web, and is especially useful for the larger, harder to lavage sharks. Marcus Drymon's talk was noteworthy in that it directly addressed my main questions about the method: how specific can it get? Is it possible to use this method to determine prey species? It turns out that when you directly observe the stomach contents, you can use the isotopic signatures of both the prey species and the sharks themselves to verify what you're finding in the diet. However, this still requires you to validate your isotope findings with gut contents, and the results really only line up well for species that have highly specialized diets (a generalist feeder like the dogfish will apparently end up vaguely in the middle of the signals of its prey, and won't give very good results). The irrepressible David Shiffman ran into exactly this problem using stable isotopes to determine the diet of sandbar sharks. He did attempt to determine the isotopic signals of his prey species, but sandbar sharks are a generalist enough feeder that no one prey species ever quite lined up.

In my editorial opinion, the isotope method shows promise but still needs to be validated by directly observing the stomach contents. Unless you have a very good idea of the shark's diet you won't be able to check for every common prey species, and this can vary widely by size, environment, and geographical area. Shark puke analysis is anything but dated; if anything, it's become more important.

-Also of note were two talks on two of my favorite sharks, the blue and the mako. Kathleen Duffy compared the diets of blue and mako sharks in the Northwest Atlantic and found that blues are a very generalist feeder, while makos are almost absurdly favoring bluefish. The diet of blue sharks has also shifted recently to include more marine mammals (always a good thing) and as a result the trophic level of blues has actually increased, making them almost even with makos. What I found especially noteworthy was that both species have recently added more spiny dogfish to their diets, coinciding with the recent resurgence of the species in the Northwest Atlantic. Strangely, spiny dogfish are more important in the diet now than they were at their peak abundance before their crash. On the Pacific coast Dr. Preti compared the diets of blue, mako, and thresher sharks, and actually got the complete opposite result from the Atlantic makos observed by Duffy. In the Pacific it appears that makos actually have the most generalized diet, though they favor a particular cephalopod. The coolest part of this talk? Both blue and mako sharks are apparently major predators of the Humboldt squid. Suck on that, squid fans.

-On the smooth side of the dogfish equation, Derek Perry studied the feeding habits of smooth dogs in Buzzards Bay, Massachusetts. What he found was that smooths are major predators of both cancer crabs (which was expected) and American lobster (which was kind of surprising to me). These aggressive little Triakids apparently exert a heavy influence on their prey: Mass DMF ventless trap surveys show lowered catch of cancer crabs during the summer, when smooth dogfish predation is highest.

-There were some good review talks as well. David McElroy put together a very comprehensive review of stomach content analyses, Joe Bizzarro presented a massive review of everything currently known about ray feeding habits (including the poorly understood sawfish and torpedo rays), and this morning Greg Skomal reviewed the general concepts behind studying stress in sharks. Today is mostly made up of stress talks, which are a little beyond my scope of expertise. That effectively concludes my review of the talks at this year's AES, but feel free to discuss anything I overlooked in the comments section.

AES Day 3 coming up

2010-07-10T18:39:00.002-04:00

I had a good run so far, but thanks to social obligations I'll have to save the Day 3 update on the AES conference for later. Stay tuned...

AES Day 2 - Day of the Dogfish

2010-07-09T19:06:00.000-04:00

Today was the day when two of us from the Rulifson lab gave our presentations (Jen gave a talk, I stood by my poster and chatted with passers-by). Perhaps by design it was also the day that the dogfish talks came out of the woodwork. Lots of interesting new data was presented that will hopefully eventually give us a clue as to what's happening with this species. I also washed all the dogfish talks down with some highly entertaining talks about tiger sharks, of both the standard and sand variety.

-The first shot fired in the dogfish blitz was from Walter Bubley, who has been working on updating the presently known data on spiny dogfish life history. His approach was interesting and I thought it really helped illustrate his findings. Basically he took the previously published data on spiny dogfish reproduction and life history and grouped that as "pre-fish pressure," since most of it was published before the real rise in dogfish fishing during the '90s. He then went out and did all the blood and guts grunt work to work out the age and size at maturity (among other reproductive factors) in the "post-fishing pressure" era. His findings? Spiny dogfish are maturing earlier (9 years instead of the previously-published 12 for females) and at a smaller average length. It's interesting to see that only about 10 or so years of fishing pressure has already affected this long-lived species in a way that we typically think of bony fish being affected.

-The next dogfish paper was from Mike Frisk, who looked at the habitat preferences of newborn spinies. This talk lead to a potentially game-changing possibility: what if the sudden drop in spiny dogfish fecundity was related to what was essentially an environmental hiccup? What Frisk found was that a sudden fluctuation in sea temperatures between 1998 and 2000 caught a whole cohort of dogfish out of their temperature tolerance. This coincides with when noticeable drops in the numbers of neonatal spiny dogfish were occurring, leading eventually to the near-state of warfare between fishermen and managers today. I'm still of the mind that fishing has a lot to do with the decline, but this is a really interesting possibility and deserves further work.

-James Sulikowski gave the next dogfish talk, and I was interested to see what he had to say since I've been hearing about his results for some time. He does have some interesting findings from his spot tagging data, though frankly I would have liked to see his talk go further into the science. Among what he's found is a huge (bordering on sensationalistic in my opinion) impact from spiny dogfish predation, and some evidence for a population that stays north for the winter (genuinely interesting). I do give him kudos for giving probably the funniest talk all conference, and I'm hoping to get a chance to pick his brain at some point, since he has done some diet work.

-Jen from the Rulifson had to follow up Sulikowski, and I thought she did a pretty kick-ass job. Her project involves using acoustic tracking techniques to trace the local movements of North Carolina's dogfish, and she's made some cool discoveries about what they're doing south of Cape Hatteras. I'm only putting up the briefest of summaries here because I've been trying to get Jen to write a guest post for a while now.

-To wash that all down, here are the highlights from some of the other talks I went to just because a.) they were badass (a given, since they all involve sharks), and b.) I knew someone involved. Karen Brewster-Geisz talked refreshingly frankly about the history of NOAA shark management, how far it's come, and how far it needs to go (worth its own post somewhere down the line). Kneebone (I've really gotta start referencing people's first names) talked about an emerging sand tiger nursery near Plymouth, Mass, which is great because it means this endangered species is potentially colonizing areas that are either totally new or once part of its former range. Brad Wetherbee (who I know from my URI days) talked about the movement of tiger sharks in the Atlantic with his characteristic dry wit. It turns out that some tiger sharks may actually spend significant time in the pelagic environment, despite the fact that, in Wetherbee's words, "they make a pretty pathetic pelagic shark."

-Occasional shark blogger Lyndell and I gave our poster presentations following the talks, and it seemed to go rather well. Though the booze did not flow as freely as at tidewater, it was still a very relaxed and conversational environment. I got some good advice and kudos from some very respected shark researchers, which is always good for the ego. Thanks to any readers who managed to stop by and check out my stuff.

Now I'm off to the AES student social, then tomorrow the first feeding symposium.

AES Day 1

2010-07-08T22:08:00.002-04:00

The first official day of talks wrapped up today, followed by a pretty sweet social at the Roger Williams Park Zoo. I'll run down some of the more interesting stuff I heard about today in relatively short form below.

-The shark talks today were dominated by stable isotope analysis. It seems like every time I talk about my thesis in a professional setting someone asks if I've tried stable isotope analysis. I know the infamous David is trying to get this type of analysis down to a fine enough scale to ID prey species, but right now it's just not at that level (he's working on it though). In my opinion it still really needs to be validated by actually looking at the gut contents (by using gastric lavage, perhaps?). Still, it's interesting what can be found out by looking at stable isotopes, and at least one talk actually used this method to improve on a classic piece of literature on shark trophic levels.

-My obsession with New England great whites was well-fed thanks to a talk by Toby Curtis, who used previously recorded data from fisheries logbooks, personal communications, and published literature to paint a picture of Carcharodon carcharias in the American Atlantic coast. There is tantalizing evidence supporting the theory that southern New England may be a pupping ground for great whites, and also that when overwintering off of Florida they may be preying upon Northern Right Whales (and also dolphins and fish, since that whale supply is quickly drying up). This talk got me pretty sufficiently geeked-out.

-Another interesting talk was given by Gulak (I'm typing this in the lobby where the internet is, and don't have the schedule handy to get his first name). Basically this was an attempt to pop-up tag a bunch of sharks in the Gulf of Mexico. They only successfully tagged a single oceanic whitetip and bigeye thresher, but saw some interesting results from both. Both appear to hug the edge of the continental shelf within the Gulf, and the tag on the thresher managed to stay on long enough to possibly show how long this species takes to reset back into normal behavior after being tagged (surprisingly long, it turns out). Very preliminary data, but still cool to see some science in action.

That concludes Day 1 of the AES coverage. Tomorrow Lyndell and I give poster talks, and Jen from my lab talks about what she's been up to with her work stalking spiny dogfish.

Dogfish on Tour: The Providence Prelude

2010-07-05T22:39:00.000-04:00

Your humble narrator is currently in the Great State of Rhode Island after a detour to the Jersey Shore to visit the Hot Girlfriend. I'll be spending time with some friends until Wednesday, when the Joint Meeting of Ichthyologists and Herpetologists gets underway. I'll be attempting to provide regular updates from the conference (including my own poster presentation) and may try my hand at some live blogging (if I have the gumption to drag my laptop to a lot of talks). I'm looking forward to meeting my fellow shark people and reconnecting with some old friends and advisors. If you're attending the conference, I'll see you there.

The Ya Like Dags? Social Guide to Rhode Island

2010-06-29T21:55:00.002-04:00

Two posts in two days? It's like I'm a real blogger all the sudden.

The occasion for this post is that next week I'll be participating in the Joint Meeting of Ichthyologists and Herpetologists. I'll be presenting a poster on my work as well as seeing an almost impossible number of shark talks thanks to the fact that the American Elasmobranch Society is rolling deep at this conference. However, being at a conference alone is not what this post is about. This post is about Rhode Island.

This particular conference is taking place in Providence, Rhode Island and is hosted by my undergrad alma mater. Aside from being able to reconnect with some of my old professors and peers as well as being able to spend some time in a state I still very much consider home, this also presents me with an opportunity to show some of my North Carolinian colleagues (and any other shark people out there who want to hang out) just how awesome my little state can be. Below the jump are some of my favorite places in the State of Rhode Island and Providence Plantations. I know that some of my old Rhody friends know of places that I've overlooked, so feel free to add any other points of interest in the comments.

In Providence
Rhode Island is very much a city-state. There's Providence, then there's the rest of the state, most of which is inhabited by people who work in Providence. This is not a function of there not being any other interesting areas in the state (I'll be covering those in a minute). It's just that given the size of the state (it could probably manage a snug fit inside some North Carolina counties) the state's settlers and developers wisely decided on having one main urban center with the rest of the state functioning mainly as suburbs, forest, and beach towns. Since the conference is in Providence and most of the attendees probably won't make it out of the city, I'll start there.

Places to drink: People drink after hours at conferences. You know it, I know it, it happens (this is apparently where I earn that disclaimer at the bottom of the main page). Providence has an excellent selection of bars for your drinking pleasure, whether you're looking for a relatively quiet place to socialize or a someplace loud and raucous. The Trinity Brewhouse is a quick walk from the Biltmore, functions as a full-service restaurant (with awesome wraps and burgers) and brews all their own beer. The upstairs is where the sitting down and eating occurs, downstairs (featuring a mounted Tyrannosaurus head) is where people get loud and pool is played. I've never had a bad beer there. Much quieter is the Union Station Brewery near RiRa (which is where some of the conference socials are happening). I haven't spent as much time there as the Trinity, but if you can handle a ferociously heavy beer, their coffee milk stout is every bit as delicious as it sounds. One of my favorite bars in the city is The Wild Colonial, which is a bit of a hike from the conference but still a comfortable walk on a nice night. The atmosphere of the place is amazing (it's built into a colonial-era brick basement and is dark and sketchy in all the best ways) it has plenty of room inside, and 'Gansett, Rhode Island's own cheap beer, is available on tap. If you want to brave Providence's College Hill neighborhood (not dangerous at all, just a hell of a walk) be sure to check out the Wickenden Pub, which has an absurd number of beers available, and is prone to combining them with tasty results.

Non-drinking activities: Most of the official material on the conference will tell you all about the Providence Place Mall, downtown shopping, the PPAC, etc, so I'll skip those. Providence is well-known for supporting live music (though truth be told a lot of the glorious old venues have unfortunately closed) and there's usually someone playing some of kind of music somewhere. One of my particular favorites is AS220, which books mostly local acts just getting on their feet and also pulls extra duty as an art studio, taco joint, and pretty sweet bar. A lot of the band that play there are old friends from my previous life booking shows at URI, and yes, I've played there too. For bigger shows you'll want to check Lupo's. If architecture and history are your things, you'll want to take a walk around pretty much the entire College Hill area, which is home to Brown University and the Rhode Island School of Design (Family Guy creator Seth McFarlane, the Talking Heads, and members of Sonic Youth are alumni) and is loaded with historic buildings, parks, and cemeteries (including both the former house and grave of the one and only H.P. Lovecraft). For people watching, you can't beat Thayer Street, with a motley collection of hipsters, artists, and college students, as well as a plethora of eateries that serve good, reasonably-priced food and stay open late.

That's a pretty bare-bones tour of Providence, and I know I skipped over a lot of worthy places, but I'd be remiss if I didn't mention some of the points of interest in the rest of the state.

Outside Providence
Just because it's not "the city" doesn't mean there's not stuff going on. I can't even begin to do justice to the rest of Rhode Island, so I won't even try. Here's a list of places I really enjoyed when I lived there, and think conference goers should check out if they want to brave leaving Providence.

The Mews Tavern: Yes, this is number one. This Wakefield tavern was my second home during undergrad, and post-grad, and pretty much every time I've visited since. They offer 69 microbrews on tap, and like the Wickenden Pub will combine them (try the Black and Blue, a variation on the Black and Tan with blueberry wheat beer in place of ale). The food is also good, I can't even count how many Rancho Relaxo pizzas my friends and I housed back in the day. If you can make it down in time for happy hour, do it.

The Ocean Mist: While we're on the subject of southern Rhode Island bars, the Ocean Mist is a great example of a true beach bar. In fact, the beach is eroding dangerously far under the building, so enjoy this institution while it lasts. Way down in Matunuck, it's pretty far from Providence and kind of out in the boonies, but worth a visit if you're feeling adventurous. It also frequently features live music and on Sundays has a hangover breakfast menu.

Boon Street Eateries: This street two blocks from the beach in Narragansett contains two of the best places I've ever eaten at: Crazy Burger and Marko's. Crazy Burger is true to its name, offering an off-beat menu of variations on the burger theme, and is also BYOB (the Hot Girlfriend and I enjoyed some leftover wine over salmon and veggie burgers there). Marko's is a tiny place (like four tables total inside) serving Lebanese cuisine, including the best gyro I've ever had. This part of Narragansett is inhabited by URI students during the school year, so both places have a good selection of vegetarian and vegan fare if that's your thing.

Narragansett Beach: Technically a town beach, and you'll be paying a premium for parking because of it. However, it's still my favorite beach in the state thanks to the great location, nice water, good surf, and interesting mix of people. The fact that I spent a couple idyllic post-grad summers in Narragansett might have a lot to do with it too. If you don't feel like hitting the beach itself you can walk along the Narragansett sea wall and watch the proceedings from there.

Brickley's: Homemade ice cream so good you'll end up eating it way too fast (you'd think I'd learn eventually). It has two locations, one not far from Narragansett Beach and the other a few blocks away from the Mews Tavern in Wakefield. Both get busy on good beach days for good reason.

Newport: This list has been very Narragansett/South Kingstown-centric, but I've got to give a shout-out to Newport. It's infested with tourists and has a brutal bridge toll (which you can skip if you take 114 from Providence) but has a lot to recommend it despite all that. If you have an extra day to kill, check out the historic downtown, buy some cds at the Music Box, have a Guinness at the Fastnet, see the ocean at the Cliff Walk, check out the massive "cottages" of the roaring '20's-era robber barons, stare enviously at the hundreds of yachts packed in the harbor, and generally have the kind of old-time seaside day you'd otherwise have to take a ferry to Martha's Vineyard to experience. To be honest, and this is the opinion of a former local, Newport hits its peak in March during the St. Patrick's Day parade, but still worth a look in the summer.

And that's my horribly biased and by no means complete guide to what to see and do in the great state of Rhode Island. As you can probably tell, I'm pretty excited to be able to go back, and I'm also pretty excited about playing tour guide. Anyone going to the conference feel free to stop by my poster (I'll be standing awkwardly by it during Poster Session 1) and if you want to know where to drink, you now know who to ask.

First New England Great White of 2010

2010-06-28T19:16:00.001-04:00

I'm headed back up to my motherland of Rhode Island next week for the Joint Meeting of Icthyologists and Herpetologists (mainly because of the heavy AES presence there), and it seems the great whites are going to be there to greet me. The first New England great white of the summer has surfaced off of Boston, where it was caught, tagged, and released by a group of Gloucester fishermen. The Dorsal Fin has a looped video of the shark taken by the fishermen. Maybe I should bring my snorkeling gear with me...

Feeding Habits Analysis: Detective Work Part 2

2010-06-24T20:37:00.000-04:00

In my previous post on the detective work necessary for any good feeding habits analysis, I lamented the apparent lack of a "one-stop shop" for looking up fish scales (at least as far as I've been able to find). In response, I've been saving scales from fishes I've been albe to ID down to species level. The idea is to match up these "type" scales with the scales often found with the unclassifiable chunks of fish that often show up in spiny dogfish stomach contents. Below the jump you'll find the first three species in Chuck's Field Guide to Spiny Dogfish Bait.

Atlantic menhaden (Brevoortia tyrannus). I've posted before on how tasty these ubiquitous cuplieds seem to be to a dogfish, and it's not surprising that scales resembling menhaden scales show up with a lot of my unknowns. Menhaden have a fair amount of variation in the shape of their scales. Fortunately, I have a lot of menhaden scale samples.

Bay anchovy (Anchoa mitchilli). These fish show up in the hundreds, usually intact. Dogfish must just swim through large schools oft these would-be pizza toppings with their mouths open. So far the highest count in any one stomach has been 253 anchovies, and they weren't even the only things in the stomach. Anchovies must pack efficiently. I'll need to get a better picture of these scales, since I'm not sure these ones aren't multiple scales stuck together.

Atlantic croaker (Micropogonias undulatus). These scales could probably be lighted better, and I'm looking to get more samples of these, because they're a pretty nondescript scale. In contrast to the anchovies, there are typically only 1-3 small croaker in any given stomach, and they don't turn up that often. Strangely, most of the croaker I've found have been in the middle of big clumps of anchovies.

Marine Rewilding?

2010-06-20T20:32:00.000-04:00

It's amazing what you'll catch in the letters to the editor sometimes. In the latest issue of Fisheries Magazine is a classic back-and-forth editorial origination from an article by researcher John. C. Briggs. At first my interest was piqued simply by the fact that there was something ocean-related (since the start of my subscription Fisheries has been utterly dominated by freshwater articles), but reading the debate motivated me to go back and track down the original article. What I found was one of the more unusual takes I've seen on the management of Atlantic fisheries, and an interesting parallel with a highly controversial conservation strategy.

The idea behind Briggs (2008) is basically this: you can replace depleted species in the North Atlantic by replacing them with similar species from the North Pacific. Since areas with low biodiversity are both more vulnerable to overfishing and less likely to recover, Briggs' idea is to increase biodiversity by intentionally introducing Pacific species to the Atlantic. Not just any species, but large, commercially-important fish like the Pacific versions of cod and halibut. In theory this provides the dual benefits of giving fishermen something to catch other than the beleaguered Atlantic species and filling the niches vacated by the overfishing of Atlantic cod, halibut, haddock, etc. Many Atlantic and Pacific species share a common ancestry, and Briggs suggests that this may be enough to help the Pacific species fit in.

As I read this paper, it occurred to me that I've seen an eerily similar argument before. The Pleistocene Rewilding movement is nicely summarized in Donlan et al. (2006), a paper epic in its scope (and authored by so many researchers that typing it into the References section takes almost as long as reading the paper). Rewilding is essentially the restoration of the North American ecosystem to the pre-human stage. North America was once the stomping ground of mammoths, giant sloths, saber-toothed tigers and other badass megafauna, and when Homo sapiens migrated over from Asia it rampaged around like a bull in a china shop, driving everything larger than the polar bear to extinction. The result is a series of gaps in the ecosystem large enough to, well, fit a woolly mammoth, from plants that were meant to be dispersed by enormous animals to grazers like the pronghorn elk that have obviously evolved to escape predators that just aren't around anymore. Donlan and company argue that the only way to truly restore the North American ecosystem is to bring in proxy animals to refill those empty niches, and a lot of extinct American megafauna was pretty closely related to currently extant African megafauna. Think elephants to replace mammoths and leopards to chase the pronghorn elk, and you've got the idea. And it immediately becomes obvious why this is such a controversial stance.

So what Briggs is suggesting is no less than a form of marine rewilding. He's not trying to bring back prehistoric species, but he is in favor of transplanting species from one geographic area to another in order to offset human impacts. The issue is that the North Atlantic has been fished since prehistory, so it's nearly impossible to tell what the "pre-human" state was. Another interesting aspect is the relatively open nature of the ocean. While the Atlantic and Pacific have more distinct species than not, a lot of the larger, more migratory species readily inhabit both oceans. The North Atlantic and Pacific both share several species of sharks (including the spiny dogfish), tuna, cetaceans, and other wide-ranging marine megafauna. Many of these wide-ranging species function as predators of both the Atlantic and Pacific species Briggs intends to transplant. Would the presence of Pacific cod benefit the Atlantic species by taking the predatory heat off as well? And would this be enough to mitigate the inevitable conflict should Atlantic cod recover enough to start taking back their old territory?

It makes for an interesting discussion, but the long-term risks and benefits of what Briggs somewhat euphemistically calls "proactive management" are poorly understood. What we do have is a long history of intentional freshwater introductions, the results of which have been spotty at best. We also have just as long a history of harmful marine invasive species. The real question is who, exactly, marine rewilding is really trying to benefit. It may refill important niches, and it may also lead to the wholesale displacement of Atlantic species (which are starting out at a disadvantage being overfished). What it does do, however, is give fishermen something to catch, which is ultimately one of the most important long-term goals of fisheries management. Is preserving the commercial fishing industry worth this massive-scale experiment in marine ecology? I'll leave that up to the Comments section.

Briggs, J. (2008). The North Atlantic Ocean: Need for Proactive Management Fisheries, 33 (4), 180-185 DOI: 10.1577/1548-8446-33.4.180

Josh Donlan C, Berger J, Bock CE, Bock JH, Burney DA, Estes JA, Foreman D, Martin PS, Roemer GW, Smith FA, Soulé ME, & Greene HW (2006). Pleistocene rewilding: an optimistic agenda for twenty-first century conservation. The American naturalist, 168 (5), 660-81 PMID: 17080364

Angry Post

2010-06-14T23:26:00.000-04:00

You may have noticed that I haven't been saying much about the white elephant (or big black blob) in the ocean. This is for two reasons: first, I try to stick to my main subjects here, which are dogfish, shark research, and fisheries management. I like to throw in some oddball internet stuff every so often but in general I try to write what I know. Secondly, the BP disaster is being covered much more thoroughly in other forums. Deep Sea News has been following the story from the beginning, and Southern Fried Science has a handy list of other places you can check to follow the progress of the oil as it destroys the Gulf of Mexico and potentially the entire Atlantic coast.

Documents released today (or at least reported on today) reveal that BP knowingly and willingly cut corners in order to save time and money. The company ignored advice from Halliburton that could have made the well much safer, and even turned a deaf ear to the Deepwater Horizon's own chief engineer, who called the situation a "nightmare well."

I guess we can stop the finger pointing now (though BP CEO Tony Hayward's appearance before Congress on Thursday should be a hoot). Yet again we see the end result of trusting profit-motivated entities to regulate themselves. Will this time finally be the time we learn that this is a bad idea?

Feeding Habits Analysis: Detective Work

2010-06-08T22:48:00.000-04:00

As anyone who's ever done a diet study will tell you, you end up getting a lot of unverifiable gunk in your study animal's stomach contents. Sometimes enough of the consistency remains that you can tell generally what this chunk of meat used to be. For example, it's pretty easy to tell fish meat from anything else thanks to identifying features like white meat and the pattern of musculature. However, getting beyond this stage takes a little more work and creativity.

Sometimes enough of the skin or some other identifying feature helps narrow it down. For instance, the skin of Cupleid fishes (herrings and shads) has a shimmery kind of consistency that really stands out once you've seen it a few times. Also, menhaden tend to have a large, olive-shaped gizzard that is one of the last pieces of the anatomy to digest. I can't tell you how many times I've been ready to classify a half-digested fish as "teleost remains" only to have one of those telltale digestive organs pop out.

And then there are the hard parts. And by that I mean the hard parts of the prey. Crustacean shells are one obvious example, but it is possible to identify bony fish at least down to a family level by scales and bones, as these are sometimes the absolute last parts of the fish to be broken down by the predator's digestive enzymes. What I've been doing is saving scales and bones that co-occur in the stomach with otherwise unidentifiable fish remains (sometimes these parts come right off the remains themselves) and photographing them using the lab's sweet Olympus dissection scope. Here's an example.

If we were fish, eventually we'd all look something like this.

Now that I have a collection of high-quality images of fish scales and bones, I need to ID them. I've already taken scales off of intact menhaden to compare to the unidentified scales, but this only works if I manage to find at least one intact specimen of every species fed upon by spiny dogfish. This is impossible in cases where the little sharks are attacking and dismembering large fish. It's unlikely I'll be finding an entire striped bass in the stomach of a meter-long dogfish (though that would definitely be awesome).

What I need now (and what I'm hoping actually exists) is a nice taxonomic guide that covers scale and bone morphology. Fishes of the Gulf of Maine is the standard I hold most guides up to, and even this classic falls short on hard part ID (for most species it includes a general description of scale morphology and vertebral counts, but I'd really like something with pictures). Also, that particular book won't cover some of the more southern species. FishBase has pretty thorough taxonomic keys, but theirs are really only useful if you have the whole fish handy. I feel like a species guide with scale and bone pictures must exist somewhere. If anyone has a good suggestion for a key with good descriptions and/or pictures of the scales and bones, let me know and I'll owe you a beer.

New England Great Whites Return

2010-06-06T21:40:00.000-04:00

Here's an incredibly timely news item, given that my last post was a little Carcharodon carcharias humor and I'm watching "Expedition Great White" as I write this. Last summer five great whites were tagged with satellite tracking tags as they hung out right off the beaches of Cape Cod. Data coming in from the tags now suggests that at least one of the tagged sharks is on its way back for the summer. There is anecdotal evidence that great white numbers are increasing off of New England, most likely due to the Cape's burgeoning harbor seal population.

This is great news for the marine ecosystem of New England, and ironically, for some surfers I've spoken to from the area. I've heard stories of bull harbor seals harassing surfers right out of the water, so some among the Cape Cod surfing community are actually welcoming the return of the sharks. Hopefully the chambers of commerce in the beachside towns of Cape Cod will be as reasonable.

This is a story I've been following as an amateur for a while. Even though the main focus of this blog is sharks of a considerably smaller size, as both a salty New Englander and a big fan of sharks in general I get pretty enthusiastic about the return of great whites to the Northeast.

New House, New Pet?

2010-06-04T20:36:00.000-04:00

I'll be moving into a new apartment next month, and I've been wondering whether I want to get a pet to take advantage of the extra space. Thanks to Rob for bringing this to my attention and helping me with the decision.

From The Onion

Woo! 50th post!

2010-06-02T21:25:00.001-04:00

6 months, 50 posts. Not a bad pace so far. As the world watches the tragedy unfolding in the Gulf of Mexico and I prepare for another boat trip out to Cape Lookout (now that we've found the holdover population, the next step is to measure and tag some of them) let's take a moment to enjoy some video of the mighty spiny dogfish. The first video shows the graceful movement and skittish behavior shown by spiny dogfish interacting with divers. The second is the dogfish as consummate mesopredator, savaging a baited camera and driving off cod as they attempt to get a piece of the action. Thanks for reading so far, and stick around for more small shark action.

The Great Memorial Day Dogfish Hunt

2010-06-01T23:21:00.000-04:00

Earlier I posted on a population of spiny dogfish that seem to be hanging out south of Cape Hatteras long after they are supposed to have migrated north. As of this past weekend stories of spiny dogfish stealing bait and chasing fish continued from the waters between Morehead City and Cape Lookout. On Monday a team comprised of Dr. Rulifson, Jen, Dan Z, and myself set out to the shallow, sandy waters on the inside of the Cape Lookout hook in search of these hungry stragglers. Read on to see how the mission went...

We couldn't have asked for a better day to fish: the water was as calm as you could ask for considering the area's hazardous history. After casting around in the sandy bottom (during which Dr. Rulifson got himself a nice fluke) and going into the water to check out a patch of eelgrass we found our first sharky spot. The first bite there was an unconfirmed spiny dogfish that got off the hook before it could be landed, then we got into the smooth dogs.

I'm a big fan of smooth dogfish, and consider them to actually be a pretty fun catch. I honestly think these aggressive little Triakids are highly underrated as a recreational sport fish. I could play with the smoothhounds all day, but we were here to verify and document these holdover spinies. So on we went.

Despite sightings of a couple possible spiny dogfish, we had yet to actually snag any. That changed when we went out into the channel leading out of the hook. First got into another few smooth dogfish, then the first Squalus acanthias appeared. Soon smooth and spiny dogfish were in fierce competition for our bait. The smooths were a mixed group of males and females of approximately the same size, while all the spiny dogs were females between 70-100 cm. The rising temperatures seemed to be having no ill effect on the sharks' health: if anything the dogfish seemed more active than usual. A couple were kept to determine if anything unusual is going on internally, the rest were released to continue providing a mystery for local fishermen and scientists.

So in conclusion, the spiny dogfish that seem to be summering south of Hatteras are definitely there. It will be interesting to see how they adapt as the temperature continues to rise. Are summer spinies a regular occurrence? As always, comments from those more experienced in these waters than I are welcome.

For your viewing pleasure, here are a some choice photos from the trip.

Cape Lookout Light. Our backdrop for most of the day.

Not a dogfish, but still a pretty good catch.

Juvenile pinfish and croaker in the seagrass bed.

Seagrass beds are also an important habitat for cheap, nasty beer.

Smooth dogs!

Shark on!

Spiny dogs, including Dan's first.

I got one!

DarWIN, not DarLOSE!

2010-05-25T23:17:00.000-04:00

I've always thought the comedic talents of both Dana Carvey and Charles Darwin were highly underrated.

Dana Carvey is "DARWIN" - watch more funny videos

Thoughts on North Carolina's Gill Net Issues

2010-05-23T17:27:00.000-04:00

It's been a hot topic in this state for a while that gill nets are both important to the commercial fishing industry and highly controversial. I personally know a couple people involved in this debate, and have been following it with some interest, though I haven't had a chance to really post anything on it until now. Which is timely, because apparently management decisions have been made.

I'll go ahead and get my personal biases out of the way here in the beginning: I'm kind of a conscientious objector when it comes to gill nets. I'm of the opinion that there are better ways of commercial fishing in terms of bycath survival (I've been planning on posting about one of those methods for a while, so stay tuned for that), and I'll be honest, a lot of my thoughts on gill netting come from a shark conservation point of view. That said, I also try to support local seafood whenever possible, and an outright gill net ban hurts a lot of local fishermen.

Like all fisheries issues, this is far from a black-and-white situation. While the need to protect endangered species is clearly a factor, what you also have happening in North Carolina is a long-running conflict between two stakeholder groups: commercial and recreational fishermen. This surprisingly even-handed article from ESPN (of all places) summarizes the conflict pretty well, particularly the opening paragraphs with the frustrated recreational fisherman finding gill nets in all his favorite spots. It appears that even in the vast sounds of North Carolina there may not be enough water to go around.

So is this an attempt to protect endangered species, or just an extension of the conflicts between recreational and commercial fishermen? Two factors make me suspicious of the motivations behind the attempt at banning gill nets. The first is the nature of the compromise management plan, according to the MFC the only plan could be agreed upon that would still allow gill netters to work. Reductions in gear size and placement can justifiably be said to lower the potential encounter rate between gill nets and non-target species, but what really strikes me is that gill netting is now restricted to weeknights. I'm wondering what the science behind that is. It's not like sea turtles, sharks, and dolphins don't venture into the sounds at night, and in fact the potential encounter rate is probably higher for turtles and sharks at night. There is one inhabitant of North Carolina's sounds that is less likely to be encountered on weeknights, however: recreational fishermen.

Which brings me to the second caveat: the presence of the CCA in this debate. The CCA refers to themselves as a conservation group made up primarily of concerned recreational fishermen. Generally fishermen getting involved in conservation is a good thing, but this particular organization is viewed with some suspicion by both commercial fishermen and fisheries managers in North Carolina. Bluegrass Blue Crab over at Southern Fried Science got to the heart of the reasons why back in March. In some cases it appears that "the lobbying efforts of the CCA are a thinly veiled campaign against competing ocean uses." It's worth considering in this debate whether the pro-recreational agenda is more important to this organization than actual conservation.

Are legitimate concerns over conservation and endangered species being hijacked to further a turf war between recreational and commercial fishermen? And if so, is it worth taking an "ends justify the means" approach if it ultimately helps vulnerable species? In this case it may even be questionable whether it's even making a difference for the species in question at all. This issue is probably far from over.

Feeding Habits Analysis: Pizza Toppings

2010-05-20T23:21:00.000-04:00

In my last post about the things I'm finding in shark puke, I discussed the presence of menhaden in the diet of spiny dogfish. These fat, oil-rich fish make quite a nutritious meal, and it usually only takes a handful of them (or chunks of one of them) to fill an average dogfish stomach.

However, there are times when the optimum meal just isn't available and you've got to go with quantity over quality. The title of this post is a big hint as to what I'm talking about here.

There's too many of them!

That's right, we've hit the anchovies. While the larger fish showed up in low numbers or in pieces, apparently all a dogfish needs to do to eat a full stomach of anchovies is just swim through the school with its mouth open. It's hard to argue with the results of that strategy: one dogfish stomach contained 253 of the little forage fish, ranging from a diminutive 30 mm total length to a fairly impressive (by anchovy standards) 70 mm. And because the majority of these fish were swallowed whole, they're so well-preserved that the subsample taken for identification easily proved them to be bay achovies (Anchoa mitchilli).

Though it's tempting to just grab the whole pile of anchovies and just get them over with, it's worth going through the chunk of fish in detail, because in at least a few stomachs some oddballs have been mixed in. A couple small croaker were expected, but one stomach offered something of a mystery: a small fish that has me and the lab shad/herring expert Dan Z scratching our heads.

Apologies for the blurriness. One day I'll get a decent macro lens.

Though it can be tough to tell from the above image (and I fully expect it to be called out as some kind of Sasquatch picture, which is why this specimen is preserved so others wiser than myself can take a look at it) that little bugger has several defining morphological features that provide tantalizing evidence that it is a blueback herring (Alosa aestivalis). It has very herring-like scales and skin (once you've seen a ton of herring you pretty much recognize the herring "look") and the head shape pretty much confirms it as one of the river herrings. Sure enough, the lining of the body cavity was blueish black, which is usually the smoking gun for identifying a blueback herring. The problem is, this would have come out of a shark caught in February, which should be the entirely wrong time of year to find a blueback this size (to say nothing of the fact that the dogfish would likely have to swim up the river to get at it). So the question is, what is this fish if it isn't a blueback herring?

It should be noted that both Dan and I are dirty Yankees, so I'll leave it up to any readers better-versed in local fish species. Is there anything swimming around North Carolina in winter that would so closely resemble a juvenile blueback herring?

Dogfish Where They're Really Not Supposed to Be

2010-05-18T12:36:00.000-04:00

Earlier I posted about spiny dogfish sticking around in parts of North Carolina when the conventional wisdom says they should be heading north (and I'm still looking for more dogfish stories from the Beaufort/Morhead City area). Well, it seems now that spiny dogfish aren't content with just being in estuaries, now they want to swim up the river itself.

Far from home. From kfvs12.com.

According to multiple sources, a two-foot female spiny dogfish was found washed up on a boat ramp on the Ohio River in Illinois. Though initially misidentified as a juvenile bull shark, this was quickly cleared up. There are a few theories out there as to why this dogfish ended up in the Ohio River, including release from a home aquarium, being left as a prank (I know of an incidence of someone leaving a dead blue shark under the diving board in a public pool as a prank), fisheries discard, or being lost from a shipment headed for biology class dissections. The fact that the spines have been removed suggests the latter, though it's likely we'll never know what caused this dogfish's extraordinary migration.

Dogfish Diets and the Influence of Holden

2010-05-15T16:43:00.000-04:00

I can never get enough of this picture. Photo by Andy Murch.

As always, I have spiny dogfish and what they're eating on the brain, and the Menhaden of History post over at Southern Fried Science and Kevin Z's challenge to the marine blogosphere got me thinking about the papers that have helped form my own meager contributions to the field of shark puke analysis. So today I'm going to try my hand at a little research blogging.

In order to get to the classic papers of shark diet analysis, you'll have to go back to the 1960s when just about all the work was done on small, common, easily captured species of cat sharks and dogfish. One paper from 1966 by M.J. Holden pretty much set the bar for the study of the diets of spiny dogfish, and was thorough enough that it's been referenced in nearly every paper since that deals with spiny dogfish feeding, and is cited in several papers and reviews on shark diets in general.

Much like modern diet studies (including mine), Holden's (1966) was motivated by fisheries. In particular he wanted to address the impact of dogfish predation on herring in British waters. To accomplish this 1,080 dogfish were captured by various methods, including the use of commercial trawlers and longliners. Interestingly, only frequency of occurrence was used in the analysis, though this makes sense in light of the fact that all Holden was trying to find was whether dogfish showed a preference for a particular species. Basically the species showing up in the majority of stomachs was determined to be the preferred prey.

The results found by Holden showed spiny dogfish in British waters to be extremely generalist feeders. Sand eels seemed to be the most common prey species, and in most cases the preferred prey were not commercially important. Most interesting for my research is the extent to which Holden went about identifying species, using scales and skeleton fragments if necessary. I'm shooting for this much detail with my own work and it gets pretty intense.

Also important was the finding that spiny dogfish are intermittent feeders, eating to satiation then holding off on feeding until the food already in the stomach is completely digested. This has been backed up thoroughly in the literature ever since and is generally accepted as true for most sharks.

One important thing Holden attempted was to mathematically determine the food requirements of spiny dogfish, finding that the total Scottish-Norwegian stock would consume 277,000 tons of food a year. While this seems like a lot, it really comes down to 1.8 kg of food for a 1 kg dogfish. This was backed up by Brett and Blackburn (1978), who determined spiny dogfish metabolism is on the low end of the elasmobranch spectrum and that a dogfish really only needs to consume 1.5-2 times its body weight per year for routine metabolism. Hannan (2009), however, found evidence of a significantly higher metabolic rate in spiny dogfish, though her sharks were relatively young and some shark species show higher metabolism in their early years. In any case, the combination of dietary preference and food requirement goes a long way towards determining the predatory impact on individual species. If there's one limitation of Holden's paper, it's that it doesn't go far enough down this road: he had a decent idea of the dietary needs of British spiny dogfish and the ratio of species in the diet, he just didn't break up that stock-wide consumption rate by species.

This could be because of the highly generalist diet he observed in his samples of spiny dogfish. Holden's sampling method brought in dogfish from several different areas within British waters, and from at least two stocks, so he was able to compare the diets and determined that the spiny dogfish is "an indiscriminate predator preying upon those species that are abundant and available in the area." Other researchers have taken this idea and run with it, going as far as to use presence and abundance within spiny dogfish stomachs as a proxy for relative abundance in the marine community. Link and Ford (2006) used spiny dogfish stomach contents to show an increase in abundance of ctenophores on the U.S. east coast, though this method raises the question as to whether ctenophore abundance has truly increased or spiny dogfish are just consuming more ctenophores.

Holden's work was very thorough for its time, and really set the tone for most subsequent diet studies on spiny dogfish and other sharks. His findings have been well-supported by more current literature, to the point where the assumptions supported by his work can be more or less accepted (though it should be obvious that using spiny dogfish as living trawl surveys is potentially problematic).

References

Brett, J.R., and J.M. Blackburn, 1978. Metabolic Rate and Energy Expenditure of the Spiny Dogfish Squalus acanthias. Journal of the Fisheries Research Board of Canada 35:816-821.

Hannan, K. 2009. Determination of gastric evacuation rate for immature spiny dogfish. Pages 253-258 in V.F. Gallucci, G.A. McFarlane, and G.G. Bargman, editors. Biology and management of dogfish sharks. American Fisheries Society, Bethesda, Maryland.

Holden, M.J. 1966. The Food of the Spurdog Squalus acanthias. Journal du Consiel Perm. Int. Explor. Mer. 30: 255-266.

J.S. Link and M.D. Ford. 2006. Widespread and persistent increase of Ctenophora in the continental shelf ecosystem off NE USA. Marine Ecology Progress Series 320: 153-159.

Feeding Habits Analysis: Tasty Menhaden Morsels

2010-05-13T21:56:00.000-04:00

This week I finally got to start diving into my dogfish stomach contents, and the results so far have been nice and gory. The post up at Southern Fried Science about the Menhaden of History really brought home the importance of these humble oily fish in the diets of just about everything bigger than them. As the quote from G. Brown Goode states, "their mission is unmistakably to be eaten."

If the mission of menhaden (of which the Atlantic species has the deceptively badass Latin name Brevoortia tyrannus) is to be eaten, then the mission of the spiny dogfish is unmistakably to do the eating. Though I've only scratched the surface of my samples so far, the gut contents I've analyzed have overwhelmingly included menhaden, either whole or in pieces. Photographic evidence of the carnage the jaws and teeth of Squalus acanthias can create can be found below the jump.

Since I misplaced my camera this week (don't worry, I found it), this gory scene was captured on Dan Z's cell phone. Apologies for all the pixels.

Dogfish put their sharp teeth to good use, carving up menhaden that when intact must have been nearly a third as long as the sharks themselves. While traditionally fishes are thought of as swallowing each other, sharp cutting teeth are a great way of overcoming gape limitation by turning one large prey item into manageable pieces. Sharks are far from the only fishes using cutting teeth this effectively, piranha and bluefish are also well known for their ability to take large prey apart (I'm still waiting for SyFy to do a movie about man-eating bluefish).

This sort of scene must be pretty awe inspiring to witness, like the sardine runs off of South Africa but with larger prey and smaller predators. Yes, the study of predator/prey interactions provides interesting data and can be very important for conservation and management, but let's not kid ourselves: we find predators interesting because predation is awesome.

How the Oil Spill Affects Fisheries

2010-05-10T14:10:00.000-04:00

Kevin Z over at Deep Sea News has an interview with fisheries biologist Dave Kersetter that explains how the oil spill in the Gulf may affect (and is already affecting) the area's fisheries. This should be required reading for anyone following the subject, and be sure to read up on the excellent coverage of the spill going on over at Deep Sea News.

Spiny Dogfish Where They're Not Supposed to Be

2010-05-08T16:53:00.000-04:00

It's been brought to the attention of myself and others in my lab that spiny dogfish have been turning up in North Carolina waters south of Cape Hatteras in the past couple weeks. According to the conventional wisdom they should all have been heading north to summer off of New England about a month ago. I was fishing down at Atlantic Beach just a week or so ago and saw no spinies, but plenty of people were pulling up smooth dogfish. However, call-ins and the fishing reports have been mentioning spiny dogfish showing up in apparently considerable numbers.

If any intrepid readers happen to catch any spiny dogfish in the Beaufort/Morehead City/Atlantic Beach area please let me know as a comment in this post. Photographic evidence would be appreciated, and can be sent to cbangley@gmail.com. Just as a refresher, here's how you identify a spiny dogfish:

Image from Maryland DNR

Spiny dogfish can be easily told from other small sharks by the spines present on both dorsal fins. Other helpful features include the lack of an anal fin and the generally dusky coloration with scattered white spots.

Smooth dogfish will be much lighter colored, have an anal fin, and lack dorsal fin spines. Sharpnose sharks can be very similarly-colored, but again will have an anal fin and lack dorsal spines. These are really the only species in the area that might get visually confused with spiny dogfish.

It'll be another couple days before I can get back down there and try to catch any dogfish for myself, so any sightings would be appreciated.

I Live!

2010-05-02T22:36:00.000-04:00

Yeah, it's been a while. I've finally dug my way out from under the end of the semester mess and after exams tomorrow I'll be a free man for the summer (at least until I start teaching). As I take a break from studying to remind you that I still exist, here are some of the things I've been remiss in writing about:

-The huge oil spill in the Gulf of Mexico. Suffice to say, it's already a pretty epic disaster, and will only be getting worse if it isn't contained soon. The problem is, the leak is from a mile down under the surface. The only silver lining is that all new offshore drilling plans have been shelved. The next time you meet someone expounding on the virtues of "drill, baby drill!" tell them to talk to a Louisiana fisherman.

-Nearly 100 Atlantic right whales gather off of Rhode Island. Pretty awesome. Especially once you realize that that represents about a third of the remaining population.

-I went fishing the other day, and all literally all I caught the whole time, while kingfish, Spanish mackerel, and smooth dogfish came up all around me, was this:

The weird thing is, I actually felt the bite.

That's all for now. Now that I'm back to posting regularly, feel free to start checking in regularly.

Lame Apologetic Post

2010-04-20T00:58:00.000-04:00

Sorry about the sudden drop in activity. It's term paper season here in North Carolina and all the writing I've been doing lately has been going towards those. There are a lot of things I want to write about here and hopefully will get a chance to post in the next week or so. Thanks for your patience, and stay tuned. There will be more dogfish goodness on here as soon as I dig myself out from under the end of the semester.

Man vs. Squid - Your Salmon Need You!

2010-04-09T20:29:00.000-04:00

And fishermen thought spiny dogfish were bad... From mbari.org.

Humboldt squid (Docidicus gigas) are undoubtedly badass animals. Growing up to 6 feet long, capable of living in virtually oxygen-free water, and occasionally cooperating to drag divers to their doom, this species doesn't even need any hyperbole to star in its own SyFy Original. I'd even consider these velociraptors of the sea more impressive than the giant and colossal squids, despite the fact that they're "merely" the third largest squid species. Why? Unlike the other cephalopod heavyweights, Humboldts occur in huge numbers, and they're spreading.

It's been old news for a while that the range of the Humboldt squid is growing. Formerly confined to the Sea of Cortez and immediately surrounding areas, this beast now swarms all the way up the U.S. west coast, from southern California to Oregon, and has even started making appearances off of Alaska. The reasons behind this sudden explosion of killer squid are still being investigated, but evidence points to a combination of predatory release and global climate change. Large sharks are among the few predators that can take down an individual Humboldt, and have been overfished in the Pacific for decades. The increased numbers of squid are finding rich feeding grounds in areas outside their range, which have been made available by rising sea temperatures. As a result Humboldt squid have joined the rising number of species moving north to Alaska.

I've been thinking about squid today because of this post on Underwater Thrills, which poses a real problem for the fisheries of the northwest. Researcher Scott Cassell has found that Humboldt squid are just as fond of salmon as we are, and just as voracious. In fact, squid that had never been exposed to salmon still gladly ate them when presented the fish in an experiment designed to simulate (as closely as possible) a "natural" encounter between squid and salmon. The results lead Cassell to some conclusions that are a little alarmist for my taste but still get the point across: we've screwed up the oceans, the squid are loving it, and they may eat all of our fish before we get a chance to. Which leads to my favorite quote of the entire post:

We must stop eating tuna.

We must stop eating sharks.

We must stop eating krill.

We need to eat Dosidicus gigas at an unprecedented rate.

Not only is this an impassioned plea to re-think our fishing practices, it's also an invitation to eat something that I've always wanted to try. See, I love calamari, and Humbolt must be like calamari steaks.

Eat Humboldt squid. The salmon are counting on you!

Ew, Just Ew

2010-04-07T21:24:00.000-04:00

As a budding marine scientist, I've had to see fish dismember themselves in fishing gear, dissect things that look like they crawled out of the Star Wars cantina, dispose of rapidly-thawing specimens dated from 2003 (while the wind was blowing the smell and pieces of the fish themselves back in my face), and of course for my thesis I'm actively encouraging spiny dogfish to puke into bags. And in no way is my experience as a wanna-be marine biologist really all that unique; in fact plenty of my fellow grad students do far grosser things on a daily basis. In marine science, you eventually start taking your strong stomach for granted.

However, sometimes something comes along that finally manages to genuinely shock you. Something so bizarre that it becomes simultaneously hilarious and disturbing, and you find yourself forcing everyone around to pay attention to it, just so you can convince yourself that you're not crazy. Here's the catch; a lot of the time it involves dolphins.

(Warning, the rest of this post will be made up of a juvenile rant about an act that is apparently legal in Florida.)

Specifically, people and dolphins. I still haven't managed to figure out what it is about dolphins that makes them bring out the crazy in people where other charismatic megafauna (including other whales) just don't. My Freshman year intro to marine biology class included one student who was double-majoring in music and marine biology so they could play therapeutic music for stranded dolphins (to say nothing of actually, you know, helping get the animals back in the water). I know there are a lot of people out there trying to do good science with dolphins, but unfortunately they face a minefield of nutjobs claiming to "work with dolphins," meaning they have to constantly prove that they don't believe they can psychically communicate with their study animals.

This particular individual, one Malcolm J. Brenner, first appeared as a commenter on Miriam's post on bad dolphin-related sci-fi over on Deep Sea News. His first appearance generated a few shocked Twitter posts, but most online marine nerds probably dismissed him as a lone weird internet troll. Even if, as you scroll down, he continues to defend his position against other readers.

Then today I noticed that Brenner has reappeared, this time linked off of Underwater Times. Yes ladies and gentlemen, this particular dolphin fan is still around, and still promoting his book. Which is titled "Wet Goddess."

I also thought it was classy that they mentioned bestiality being legal in Florida.

While I don't have any hard data to back this up, I really only see this level of insanity with dolphins. True, cephalopod fans have to deal with the stigma of hentai, but at least in that case it doesn't involve real animals (I hope) and both supporters and detractors acknowledge how weird it is.

Seriously, what is it about dolphins?

Rhode Island Flooding

2010-04-02T21:48:00.000-04:00

The Warwick Mall in Warwick, Rhode Island. Photo from the Providence Journal.

I've been really remiss on posting about this before, but the state of Rhode Island was nearly sunk by heavy rainfall this week. The rain has finally stopped and the floodwaters are starting to recede, but Lil' Rhody will have a long way to go to recover. However, the water rose high enough to cover several sewage treatment plants, which could spell disaster for the both the beach season and the state's fisheries, two of the main economic drivers in a state that was second only to Michigan in being hit the hardest by the economic downturn. Shellfishing has been shut down north of Black and Sakonnet Points; for those unfamiliar with Rhode Island geography that shuts out pretty much the entire Narragansett Bay. Rhode Islanders can probably look forward to serious water quality problems for years to come.

To say that Rhode Island has figured prominently in my life would be a massive understatement. I learned to love the ocean by playing in its tide pools as a kid, went to URI as an undergrad, and even worked for the Rhode Island DEM for a time. Numerous pictures of the damage are floating around on the internet, most of places that I used to either frequent or drive by on an almost-daily basis. So far I haven't been able to find anywhere to donate to help out, so if anyone finds something along those lines let me know so I can post it here.

Route 95 near T.F. Green airport. From the Providence Journal.

CITES and Sharks - The Sordid History

2010-03-31T22:18:00.000-04:00

I wanted to post this earlier while it was still a bit more timely, but then real life got in the way.

The big news last week was the complete smackdown of conservation efforts for marine species at CITES (even the porbeagle, initially thought to be the one success story, got hosed). The marine blogosphere (including this blog) cried foul; Southern Fried Science gave us the list of failures, and Guilty Planet lamented the inability of policymakers to think of fish as wildlife.

It was about this time that I went back to a book I had read a few months ago, Biology and Management of Dogfish Sharks (a great source of info if you like your sharks small and numerous). Sonja Fordham from the Ocean Conservancy contributed an excellent chapter on the history of dogfish and shark management in both the US and internationally by CITES, and it should be essential reading for anyone interested in the political side of conservation.

As a primer for anyone who may be unfamiliar with the CITES process, a species can be listed under one of three Appendices, each corresponding to a certain level of international protection. Appendix I is the money shot; it's a complete ban on international trade. Appendix II is where strict control is placed on international trade, and this where just about everything that was up for listing this year would have ended up. Appendix III is the listing for species that are managed within a specific country's jurisdiction but would require one or more other nations' cooperation. An example of this would be if dogfish were protected off the U.S.; it would require cooperation from Canada due to the fact that the U.S. stocks migrate in and out of Canadian waters.

As mentioned in my previous post about CITES, strict control of international trade on dogfish would effectively kill the fishery. Virtually no one in the U.S. gets excited about eating spiny dogfish, but they've been used for fish and chips in Europe for decades (mainly due to the collapse of cod in European waters). For this reason dogfish populations are critically low in Europe and thus there is a decent export demand for dogfish landed in the States. For fishermen this is a win-win; reduce the population of a pest species while being able to profit from a species that historically existed only as (sometimes massive amounts of) bycatch.

From a scientific and management perspective, dogfish are a time bomb. Long-lived, slow-growing, and with a two-year gestation period, spiny dogfish are theoretically the worst possible species for a targeted fishery. Paradoxically, they can be almost ridiculously abundant in certain areas. Because of this the disconnect between fisheries and managers tends to be more pronounced in the case of dogfish than just about any other species. Managers see population trends that make very conservative management seem like a good idea while fishermen are pulling up 10,000 pounds of a supposedly-endangered species in one tow.

This little bit of background serves to illuminate two important factors brought up by Fordham (2009), and my main point.

The first of Fordham's points is that despite our occasionally god-awful reputation internationally when it comes to conserving natural resources, the U.S. has been a leader in shark conservation. One of the earliers CITES elasmobranch proposals was back in 1997 when the U.S. attempted to list all sawfish species. Three years later they would team up with the U.K. to propose basking sharks for listing, and in 2002 basking and whale sharks would become the first shark species listed by CITES (on Appendix I, no less). The U.S. would again be integral in listing the great white on Appendix II in 2004.

In the case of dogfish, the U.S. has supported the listing of the species much to the chagrin of fishing interests and protest from entire states. Nearly every attempt to list dogfish under Appendix II has been met by formal protest from the Division of Marine Fisheries in Massachussets, and at least once from the state of Washington. These have been tough decisions on both sides: the states are trying to support their fishermen (both states are epicenters of the dogfish fishery on their respective coasts) for exactly the reasons brought up earlier, while the U.S. delegation is forced to go against a vocal portion of their own constituents in the interest of conservation.

The second of Fordham's points is that while the U.S. has been supportive of dogfish conservation internationally, it has been the European Union (with Germany at the forefront) that has actually been putting out these dogfish proposals. Again, we can look to history for the reason. The European spiny dogfish stocks have been overexploited for a long time, and their depletion demonstrates exactly what happens without smart management of the species. So what we see at CITES is an alliance of sorts between a region that has already seen what bad can come from dogfish overexploitation and a country that is in the initial, highly contentious stages of dogfish management. The U.S. supported the proposal, but the attempted listing of spiny dogfish (and porbeagles) has been a product of Germany every time.

My main point? In the conservation and science world, it is always important to know your history. Multiple sources will tell you that the big defeats at CITES were the product of a "concentrated effort" by Japan, China, and others to prevent anything marine from being listed. That's the big picture, but as we can see from the dogfish debate there are all kinds of little side-plots if you know where to look. Japan and China couldn't have accomplished this on their own; what other countries contributed and what interest may they have had?

Don't get me wrong, I am pro-conservation, and the failure to list the large sharks is shameful and driven largely by greed. These aren't being exploited as a food source for the working class; shark-fin soup is a luxury item and utterly frivolous as a food ingredient. However, it's important to remember that conservation is about winning hearts and minds, and to do that you need to know why people exploit a species and what it may mean to them if they can't anymore.

Sonja Fordham does a much better (and far more thorough) job of explaining the sordid history of international shark management. As said before, this should be required reading for anyone interested in shark management, conservation, and even the CITES process.

Citation

Fordham, S.V. 2009. Conservation of Atlantic spiny dogfish under U.S. law and CITES. In Gallucci, V.F., McFarlane, G.A., Bargmann, G.G. (editors) Biology and Management of Dogfish Sharks. pp. 411-423.

Tidewater Recap - Only a Week Late

2010-03-27T22:12:00.000-04:00

Last weekend some members of ECU's AFS student unit (including yours truly) headed up to Annapolis, Maryland for the annual meeting of the AFS Tidewater Chapter (which includes fisheries professionals and students from Delaware, Maryland, Virginia, and North Carolina). Not only was this my first true fisheries conference, but I also gave a poster presentation on my work so far. Here's a short form recap of the weekend, and a couple (non-incriminating) pictures.

All photos by Wayne.

The speaker clearly has trouble with his name tag.

The poster presentation was the first event of the conference, and ECU was well-represented here. Aside from my own meager body of work, Dan presented his poster on river herring nursery habitat and Jacob talked at length on his work with striped bass (I'll have them chime in about their work someday. It is very interesting stuff, even if it's not shark-related). Though mine was the only shark poster there (and got a decent amount of attention for it), there were several others that were interesting to me from a diet/large predator standpoint. These included Paul Ruderhausen's poster on the feeding ecology of large pelagic fishes and Joe Facendola's study on the diet of red drum (he actually used gastric lavage to extract the stomach contents! Unfortunately I never got a chance to catch up with him and see how it worked out). Marissa Brady's work with mark/recapture and telemetry of American eels took home the top poster prize.

I actually really enjoyed the poster presentation part of the evening. Basically you stand near your poster (usually with beer in hand) and answer any questions given to you by the readers. I think I actually prefer this conversational style of presentation over giving a full-blown talk, though I'll withhold final judgment until after I've given a talk in a professional setting like this. It was all very low-key, and it was encouraging to see that a lot of the "audience" interested in what I was doing. I got some very good advice on where to go with the analytical side of my diet study, and got to meet Jack Musick, hopefully without looking too foolish (again, beer in hand).

That night we made our preliminary exploration of the Annapolis area and were impressed with what we saw. And that's about as in-depth as I'm at liberty to go.

Beginning the second morning was a full day of presentations. Much to my chagrin I was still paying for disappearing from school for three weeks to play with dogfish, so I had a take-home exam that caused me to miss a good chunk of the talks. The rest of the ECU crew filled me in on what I missed, though obviously it wasn't the same as actually being there. The entire first half of the day was dominated by striped bass, so Jacob was all over that. Of interest to me were Alison Deary's presentation on tuna habitat, Edward McGinley's use of fatty acid signatures to determine striped bass diet, Matthew Breece's work with Altantic sturgeon, and Paul Ruderhausen's talk on survivability of circle hooks (of interest to me as both a recreational fisherman and a fan of large fish). Our very own Cecilia Krahforst picked up first prize for student presentations with her work on the use of acoustics to monitor fish populations.

The social was at the Chesapeake Bay Foundation. The building itself was unique in that it was designed to be totally green, all the way down to compost toilets (which surprisingly didn't smell bad at all). Beverages were provided by the always excellent Dogfish Head Brewery and featured the Shelter Pale Ale, which I'd never had before (despite it being based on their original recipe) but will be drinking frequently in the future.

The ECU crew. Can you spot your intrepid author?

That night we again explored Annapolis. Obviously, science was discussed.

Saturday morning's talks were almost entirely about blue crabs (it is Maryland after all). I missed some of these talks tracking down breakfast, but Dan and Ceclilia saw all of them and Dan reported that the tethering experiments were "hilarious" (the idea behind these is that the crabs are basically tied to a stick and left to be eaten. This aids in determining natural mortality and applying gallows humor to a decapod).

So my first real conference experience was a good one, and a valuable one. I'll be taking my dogfish project on the road again in July when I present a poster at the Joint Meeting of Icthyologists and Herpetologists in my old motherland, Rhode Island. It's sponsored by URI, so I hope to make my undergrad alma mater proud.

Porbeagles Rejoice!

2010-03-24T23:35:00.000-04:00

This porbeagle is psyched. Photo by Andy Murch.

After the doom and gloom CITES news, it looks like not every animal up for listing got hosed. News is trickling in that despite the inability of the UN to agree that polar bears need protection, porbeagles managed to make Appendix II. This is great news for a species that has been in trouble for a long time, even if the Canadian population is starting to annoy some commercial fishermen. I sure am going to miss bluefin tuna, though...

CITES Results

2010-03-23T11:55:00.000-04:00

The Southern Fried Scientist sums it up rather nicely.

No protection for anything at CITES.

Thanks for comin' out.

Ocean Conservation Smackdown at CITES

2010-03-21T20:57:00.000-04:00

The Tidewater meeting went well and I'll have a recap of that soon, but I decided the results of the latest CITES (U.N. Convention on International Trade in Endangered Species) vote should be commented on first. Read on to see just how trying it can be to be an ocean conservationist.

Southern Fried Science and Deep Sea News have been covering this pretty well, and this particular CITES vote has had my attention because spiny dogfish were one of many shark species up for inclusion in Appendix II. Appendix II is the listing for species that endangered enough to call for significant restrictions on international trade. Aside from dogfish, porbeagles, three species of hammerheads (smooth, scalloped, and great), dusky sharks, sandbar sharks, and oceanic whitetips were up for listing. Also of particular not for fisheries scientists and ocean conservationists were bluefin tuna and polar bears.

Spiny dogfish caught my attention because 1.) they're my study animal, and 2.) the ongoing controversy over their endangered status in the U.S. Listing on Appendix II for this species would be undoubtedly good for the sharks (particularly the nearly fished-out European stocks), but potentially devastating for U.S. fishermen landing dogfish. The main reason a fishery exists for spiny dogfish is for export to Europe for use in fish and chips. If international trade is restricted, unless spontaneously a market develops for them in the U.S. the dogfish fishery will be effectively shut down. I can only imagine what local fishermen would have to say about that.

Judging from the track record of listing species so far, they may not have to worry about it. First came the news that a non-binding resolution related to shark conservation was rejected following a tough stand by China, Japan, and Russia, who managed to rally several developing nations around them. This resolution simply called for increased transparency in shark trade, and its rejection doesn't bode well for those shark species awaiting Appendix II listing.

Next came the news that the proposal to list bluefin tuna was rejected by a shockingly wide margin. Also noteworthy in that story is the failure to list polar bears. The fact that two species that have been the subject of so much international concern could get smacked down so handily demonstrates that, for whatever reason, the U.N. seems to be an especially hostile environment to conservation right now.

David at Southern Fried Science has linked to this editorial by Edward Dorson, director of Conservation Strategies at the Shark Research Institute. Dorson sums it up pretty well, and hopefully CITES will see reason (and actually start doing its job) before the voting is over. Spiny dogfish may be a controversial listing, but the other sharks species up for inclusion are certainly deserving.

Stay tuned. It could get ugly.

Dogfish on Tour

2010-03-16T22:37:00.000-04:00

One of the perks of being a grad student is that you're considered professional enough to be sent to conferences in your field. This weekend I'll be at the annual meeting of the AFS Tidewater chapter in Annapolis, MD. I'll be giving a poster presentation on my work so far on Thursday night, so if you're attending this event or are in the area stop by and cheer me on or heckle me mercilessly. Several of my lab-mates and fellow grad students will be there as well presenting their work.

Spring Break: Continental Shelf - Scoreboard and Conclusions

2010-03-16T00:00:00.000-04:00

Now that I'm back in NC and (relatively) settled, here's the scoreboard and final thoughts on my time aboard the Bigelow.

Gut content samples collected - 146
Dissections to verify efficiency - 32
Stations towed in North Carolina waters - 40
Stations sampled for gut contents - 14
Largest mass of dogfish in one tow - 12,730.16 kg
Largest number of dogfish in one tow - 2,738

Overall I'm pretty satisfied with those numbers. For my first time sampling off a fisheries cruise I think I did alright, especially since the big deck tows of dogfish provided me very little time between tows. Between this set of sampling and the 250 samples headed my way from the Cooperative Winter Tagging Cruise (thanks, Dr. R) I should have enough dogfish puke to last me through the summer. Now the real fun begins...

Here are some things I learned on this trip:

Spiny dogfish are hard core. Make no mistake, trawl surveys are not kind to fish. Crammed into the cod end of a trawl net, impaled on one another's spines, and in some cases nearly dismembered by the gear itself, these little sharks aren't in for a tickling contest. And that's before they're sent through the checker, tossed into baskets, and measured (and some jerk rams a tube down their throats). Most of the bony fish in this situation are mercifully dead by the time they get into the checker, but the elasmobranchs almost seem relatively unfazed. The dogfish in particular are amazing in their survivability, happily turning upright and swimming off the second they hit the water. If nothing else, this cruise has given me a new respect for just how hard it is to kill a dogfish (which is good, since part of my project is nonlethal sampling).

The scientific literature is right (for the most part). It turns out that most scientists who have studied the distribution patterns of spiny dogfish were pretty much on. We saw almost no dogfish until crossing into North Carolina, where the inshore stations saw large females almost exclusively. Once the ship had looped around to the offshore stations we started hitting large numbers of males and juveniles. Of note: south of Hatteras only one tow actually caught any spiny dogfish (smooth dogfish largely replaced them in that area) but managed to get a pretty large aggregation. Also, once out of North Carolina we started seeing mixed tows of large females, mature males, and pups. Something very interesting must be going on there.

My facial hair is disappointing. After getting back out to sea after the repairs I decided I wasn't going to shave until after the cruise and in the process grow a nice gnarly field work beard. I had high hopes, since normally going a mere two days without shaving results in an almost razor-breaking forest of stubble. However, this was as good as it got:

Who you callin' scruffy?

After about five days the "beard" stopped and stayed in the same hedgehog-esque, noticeably itchy state until the end of the cruise. I think my facial hair requires a bit more training before I turn it loose.

So that's my take on the Epic of the Bigelow. Stay tuned for the analysis and of course more witty observations on spiny dogfish, grad school, and life.

Sharks vs. Cephalopods - The Battle Continues

2010-03-12T09:32:00.000-05:00

A brief intermission from Spring Break: Contintental Shelf (I'll have the final data scoreboard up soon). I wanted to post on this earlier but was busy puking dogfish. It looks like more shots have been fired in the never-ending conflict between sharks and cephalopods.

A little history: sharks have long been in conflict with octopi and squid over who gets to be the badass rulers of the ocean. A certain YouTube video of a Pacific giant octopus taking out a spiny dogfish in an aquarium fanned the flames, though all true elasmophiles know that giant octopus show up frequently in the diets of larger Pacific sharks. Then Mega Shark Vs. Giant Octopus was released, and the conflict exploded into full-scale war (at least in my house; I used to room with noted cephalopod freak Matt). Though Sharktopus may represent a first step in the peacemaking process, the conflict continues unabated.

That's a lot of links.

The latest news from the battlefield is that the shark heavyweight may be regularly taking out the cephalopod heavyweight (tip o' the hat to Dan for the link). Micheal Domeier has been satellite-tagging great white sharks and has tracked them to an apparently barren part of the Pacific. However, this area does have a plethora of squid, including the much-feared Architeuthis, and is already utilized as a feeding ground for sperm whales. The sharks in this area are making deep dives, and at least one massacred giant squid was found floating around.

As the article points out, Domeier does have a habit of making the most of his screen time, and his methods have been controversial. However, when it comes to sharks I'm about as fair and balanced as Fox News, so in your face, squid freaks!

Also came the news that the dogfish vs. octopus video was staged. So sad that cephalopods have to resort to blatant propaganda...

Now that I've thrown around all those fightin' words, what say the cephalopod fans?

Spring Break: Continental Shelf - Day 16 - Heading for Home

2010-03-10T16:51:00.000-05:00

Sunrise on the last day of sampling.

Well, all good things must come to an end and Spring Break: Continental Shelf is no exception. The last sampling station was towed earier this afternoon off of Delaware Bay, and now the Bigelow is steaming back to Newport, where I'm told we'll be docking sometime before lunch tomorrow. I'll be taking a break hanging out in Newport with some friends for a few days after, so if you're in the Rhode Island area let me know.

Thanks to everyone who's been reading so far, and do stick around. There is plenty more red hot spiny dogfish action (not to mention shark-related nerdiness) on the way. Now that I've collected all this data, it's time to see where it all goes.

Spring Break: Continental Shelf - Day 15 - Winding Down

2010-03-09T16:55:00.000-05:00

Sorry about the lack of updates yesterday. There were two deck tows and all the rest were huge hauls as well. All I wanted to do after my shift was sleep.

Also, the last North Carolina station was towed at the beginning of my shift yesterday, which means I've lavaged every dogfish I'm going to get for this cruise. Now it's time to take stock of the data I've collected, enjoy being a normal volunteer crew member, and catch up on school work (internet access at sea is a double-edged sword). I've also gotten copies of the raw data from the tows, so I'm already taking a preliminary look at any trends that might be popping up.

So while I relentlessly copy down data, enjoy this picture of the spiny dogfish's jaws of death.

Spring Break: Continental Shelf: Day 13 - Dogfishpalooza or Dogfishpocalypse?

2010-03-07T15:51:00.000-05:00

While the catches heading south in the near-shore stations were dominated by massive, mature females, the trawls heading back north through the offshore stations have hit the mother load. I've been frantically trying to get data on all the smaller and male sharks while I'm still in North Carolina waters so I can even out the demographics on my study. Unfortunately there are fewer sampling stations heading north so I'm trying to do more with less while hopefully preventing any one tow from biasing the data.

Which is tough to do when some of the tows look like this:

10,000 pounds of dogfish. Seriously.

Tows like this are at least partially responsible for the bad reputation of dogfish among just about anyone who ever has to tow a net or fish with any gear whatsoever. However, scientifically, they're very interesting. This particular aggregation had some of the largest females I've seen yet, and almost as many mature males. What's more, most of the females were very pregnant, and the pups were pretty much ready to come out (and in some cases did, right on the deck). I'm not sure if anyone's done any work on this kind of tow, but it could be significant.

That said, my study is on feeding habits, and big dogfish tows actually provide less-than-optimal data for my research. Aside from having to heavily subsample in order to avoid biasing the overall study, this dense a catch presents a number of problems when sampling for stomach contents. Obviously cramming two thousand dogfish into one net heavily stresses the sharks, and one of the most common reactions to stress among fish is to expel the stomach contents. And dammit, I want to expel those stomach contents!

Also, these tows present a frustrating catch-22 for sampling design. Doing my sampling during a working research cruise means I need to fit it in between tows when I can. Not only that but I often need an extra pair of hands to take down data and/or hold bags to get this done with any appreciable efficiency, which necessitates someone else having some free time. Working up a tow this size eats up most of the time until the next one, and only in drastic situations will the ship break procedure and hold off on the next haul. So while the catch shown in the picture contained several demographics and literally thousands of sharks, I only had time to lavage fifteen of them before the net came in for the next station.

The North Carolina sampling is pretty much done at this point, so now I get to relax in my off-watch and take stock of what I've recorded. There is still some deep water sampling off of Virginia and Delaware, so stay tuned and see if we catch anything interesting. It's been quite the ride and it's not over yet.

Spring Break: Continental Shelf - Day 12 - Southern Safari

2010-03-06T17:36:00.000-05:00

Most of day 12 was spent south of Cape Hatteras trawling some very interesting subtropical species. With the exception of one tow, spiny dogfish were virtually absent from the area (though when they did decide to show up they showed up in numbers). Which isn't to say there weren't plenty of other sharks to keep me occupied (see below the jump).

I was hoping to get some lavages south of Cape Hatteras and wasn't disappointed when the opportunity presented itself. Though spiny dogs are known as a temperate/cold water species, when in warm waters they'll gladly eat warm water species. Some of the most interesting and colorful stomach contents were found in that one tow.

Now that we're north of Hatteras we're running into massive schools of dogfish, which are still dominated by mature females but are finally starting to include significant numbers of males. This provides the opportunity to compare diet by sex within the same school. Tomorrow will be another long sampling day (and then after that I believe we leave North Carolina waters).

And now that you've suffered through the boring back story, here are the shark pictures:

It's going to be a good watch when the first tow is loaded with sandbar sharks. We actually ran out of shark tags from this one night of sampling.

Your intrepid author releasing a sandbar shark.

The sun came up, and so did the sand tigers. That's THREE in one tow. All larger than the one from yesterday.

Two sand tigers waiting patiently to be measured and released.

Forget everything you've ever heard about any other shark. Angel sharks are the single most hazardous shark to handle. Ever.

Spring Break: Continental Shelf - Day 11 - Crossing the Border

2010-03-05T16:20:00.000-05:00

Two posts in one day! Enjoy while it lasts, I may never manage this again.

Today the Bigelow made it past Cape Hatteras to do a little southern sampling. I'd hoped to get some spiny dogfish diet data from south of the Cape but it appears that at least this far offshore the spiny dogfish switch is set to "off." This is very interesting given that my own major professor and several of his students have done quite a bit of work on spiny dogfish south of Cape Hatteras. At least as far as this cruise is concerned, the spinies have been replaced with smooth dogfish.

That said, I managed to get nearly a hundred successful lavages in before crossing south of Hatteras. The entire fish community really does shift here, and this was exemplified by this first tow in the area, which brought up something completely different...

Something lurks beneath this pile of croaker, spot, and smooth dogfish.

The Bigelow is equipped with a large animal sling just for situations like this. By the way, that's an adult female sand tiger shark.

Measurements were taken and the shark was tagged. You can tell by the skin tone that it's still winter conditions in the water. Yes, sharks do tan.

After being measured and tagged, the 2.3 meter (over 6 feet!) shark was lowered back into the water.

Badass stuff, even if the spiny dogfish action has dropped precipitously. Right now I'm taking the opportunity to relax (and catch up on some school-related work) in preparation for another marathon sampling session. We'll be looping back up through the offshore stations off of North Carolina, where I expect to pick up dogfish from some different demographics.

Spring Break: Continental Shelf - Pictures from Day 10

2010-03-05T15:27:00.000-05:00

As promised yesterday, here are pictures from yesterday's sampling fest. Behold the glory of gastric lavage.

Thanks to Geoff for helping with the photography while I was busy inducing vomiting.

First you've got to get the tube in. It looks uncomfortable, but it beats getting cut open.

Flush with water, than lift by the tail. Then take the obligatory vomit shot.

Mmm... stomach contents... That's a spotted hake in the bucket and that nastily-bitten hunk of fish in my hand is a partially-digested tonguefish. Tonguefish are so far one of the few food items that have proven problematic with the stomach tube method.

Unless it's one of the few doomed to be sacrificed to measure the method efficiency (by comparing food lavaged out with food dissected out), this poor hung-over dogfish will swim away from this.

Spring Break: Continental Shelf - Day 10 - Sampling!

2010-03-04T18:01:00.000-05:00

Just got off a watch and a half of dogfish sampling, and it was encouragingly productive. I had been intimidated by the low catches we were getting off of Delaware and north of the Chesapeake Bay but as soon as we crossed the North Carolina state line it was like someone flipped on the dogfish switch. There haven't been any obnoxiously huge dogfish catches so far, but it has been a comfortably steady 6-17 dogfish per trawl today. I stayed for a few tows after my shift was over to make sure I had extra coverage for the North Carolina stations. Here's the scoreboard as of right now:

7 North Carolina stations towed
53 North Carolina dogfish lavaged
17 dissected to gauge efficiency (all others released, some of these were from outside NC waters)
All sharks were females over 70 cm total length

I'll have pictures and commentary up tomorrow (plus a whole new day of sampling), but for now I am beat. I'll be having visions of spiny dogfish circling my head.

Spring Break: Continental Shelf: Day 9 - Heart of Darkness

2010-03-03T15:38:00.000-05:00

The ship is currently hanging out at the mouth of the Chesapeake Bay to avoid some weather, so sampling has been suspended for the day. For a while the seas were among the roughest I've seen, and then when snow started flying I just had to get some pictures. Even the seasoned members of the crew were making Deadliest Catch references.

At this point of the cruise I'm starting to feel like Martin Sheen going up the river in Apocalypse Now. At some point tomorrow we hit North Carolina waters and I get very busy. I'm hoping that we get a good chunk of the NC stations done during my watch, but that depends on how many Chesapeake stations we have to get through first. Either way I'm probably going to be up for the entire day tomorrow frantically collecting dogfish puke. Much coffee will be consumed. I'll probably be hallucinating by the end.

On the plus side, I've taken the liberty of testing the efficiency of the tube lavage method. Basically this means that I'm performing lavage on the dogfish already doomed to be sacrificed for the Bigelow's own diet data, and comparing the weight of what I get them to spit up to what's left in the stomach. After a few minor tweaks I'm getting near-100% efficiency, which is awesome! We'll see how that holds up when I'm trying to sample 20-30 dogfish per tow in the next couple days.

Nasty weather pictures below the jump.

Doesn't quite do the weather justice, but you can see the snow buildup.

These pictures were taken through the portholes in the wet lab, since I didn't want to risk getting tipped overboard. My policy is to only put myself in mortal danger for shark pictures.

Spring Break: Continental Shelf - Day 7 - The Dogfish Have Landed

2010-03-01T16:37:00.000-05:00

Not a whole lot to update on today, except that spiny dogfish have started showing up in numbers in the trawls. This is a good sign, as it seems the general trend is that they're getting more abundant as we travel south (we're currently working our way down past Delaware Bay).

Overexposed dogfish.

The interesting thing about the dogfish we've been catching is that so far they've all been nearly fully-grown females. This goes against what the literature has lead me to expect, since most of the conventional wisdom on dogfish is that the large females are close to shore and the males are offshore where the Bigelow would catch them. Instead I've seen mostly large, mature females, and these have been more abundant in the offshore samples. This may have to do with the low water temperature in the New Jersey/Delaware stations, and goes a long way to explain the prevalence of skates in the trawls. It'll be interesting to see how this breaks down once we get off of North Carolina.

Spring Break: Continental Shelf - Day 6 - First Sampling

2010-02-28T15:44:00.000-05:00

After hanging out in port for a couple days, the Bigelow is now ship-shape (I will never apologize for puns) and spent yesterday steaming down to the first sample sites off of New Jersey. Being on the midnight-noon watch, I was on hand when we hit the first station. Of course, being one of the newbie volunteers, I snapped pictures like a ravenous tourist (kudos go out to fellow volunteer Mary who snapped some of the "at-work" photos while I was helping work up fish). My own thesis sampling won't start until we hit the North Carolina strata later this week, but aside from being part of how I earn my keep aboard the ship, these early tows are important for helping me get the rhythm down and know how to fit my own stuff in.

Pictures and play-by-play commentary below the jump.

The Bigelow runs its catch through a conveyor belt system from the deck into the wet lab. The wet lab contains several sorting stations and three work stations with electronic fish boards and touch screens for data recording. All in all, a pretty high-tech situation for someone used to getting by with a bunch of baskets and a couple wooden fish boards. From the tows I participated in today, it all seems to work pretty efficiently (though I haven't seen a true glut of fish yet).

After being brought up in the net, the catch is deposited here...

...and ends up in here, where the fish are sorted and measured. The steps to the left go over the release chute, where the fish are returned to the water after we're done with them. Of course realistically, not everything lives.

Some jerk entering data. Really, who wears a hat in the wet lab?

Skate-tastic! This is actually an extremely small catch of skates.

Overall we didn't catch much in the first four stations. The most diverse by far was the first, which boasted winter and little skates, a few ocean pouts, lots of sea herring, a few species of small hake, a couple mackerel, some windowpane flounder, and a rare solo spiny dogfish (a large female over 90 cm in total length). The rest of the hauls were dominated by little skates, and even then only included about two dozen tops. This is apparently not uncommon for trawls off of New Jersey in February; even for fish this is off-season at the Jersey Shore.

At certain points it was actually possible to spot Atlantic City from the deck. Try as I might, I couldn't get my camera to focus enough to make out the casinos through the near-shore fog, even though the skyline was maddeningly obvious to the eye. A camera upgrade might be in order soon.

Spring Break: Continental Shelf - Pictures from Days 1 and 2

2010-02-25T22:17:00.000-05:00

The laptop has officially been cleared for the ship's network, so in the future I'll be integrating pictures into the posts. For now though, read the previous post and see if you can match these pictures up to it.

Home for the next two and a half weeks.

The hardware.

Cliffs of Block Island during the shakedown cruise.

Pixelated boat party south of Block Island. Gotta love digital zoom.

Newport Bridge at night. In shaky-cam.

View out the porthole. Clearly the weather was foreshadowing seasickness.

They can't all be nice days. This was before it even got rough.

This boat has a boat on it. Your point is irrelevant.

Sadly no pictures of interesting marine life yet, and with the boat in port getting worked over it'll probably be a couple days, but stay tuned and sooner or later I will at least have an action shot of a puking dogfish.

Spring Break: Continental Shelf - Days 1 and 2

2010-02-24T18:45:00.000-05:00

Sorry about the lack of updating yesterday. Like any good marine biologist I've been sidelined with a massive case of seasickness. I seem to be over it now so here's a quick recap of the past couple days. Pictures will be added in a future post after my laptop get scanned for viruses tomorrow.

Day 1 - Launch

After clearing things up at the pass office, I'm finally able to get onto the Navy base where the Bigelow is docked. I get my stuff on, meet everyone who's onboard so far, and settle into my room. It turns out that about half the staff and volunteers will be meeting us on the water via small boat, which seems pretty badass to me.

Day 1 is mainly made up of a shakedown cruise out to Block Island and back, during which I mill about, socialize, make sure all my gear is secured, and snap pictures like the tourist I am. Later that afternoon the remainder of the crew show up, we do the orientation and safety drills, then set off in earnest. There are rumors of foul weather on the way, but I mentally scoff at them. "Will I even feel swells on a boat this size?" I think. "Besides, I never get seasick. It'll be fine..."

Day 2 - In Which Chuck gets Seasick

We hit the foul weather about two-thirds of the way through Day 1, and I get through that without any noticeable discomfort. Then I sleep, a nice little 6-midnight doze due to being on the "night" shift (midnight - noon). When I wake up, I'm fine. Get dressed, fine. Brush my teeth, feeling a little off from the toothpaste but I chalk it up to dehydration. I grab a drink of water on the way up to the ready room. We don't have much to do other than hang out until theoretically we find a break in the weather and start sampling about halfway through the shift.

Unfortunately, the ready room is two decks up from my room, so there's that much more height to sway back and forth. I make it about half an hour then decided I need to go to the bathroom. I have about half a second of warning once I get out into the hallway before everything I ate yesterday reintroduces itself to my mouth. In desperation, I try to cover it with my hand, which anyone who's ever puked for any reason knows is always a completely futile gesture. This just means that instantly bits of my salad from dinner are all over the hallway and all over my hand.

That's right, first day truly out on the water and I boot all over the hallway. I am awesome at first impressions.

Fortunately, this was just laughed off by everyone (after I cleaned it up, of course). Usually the pattern is to sail through good weather so everyone can gradually get their sea legs, but this time we sailed right into the teeth of some major maritime grossness. As a result, half of everyone else is also seasick. This is cold comfort as I proceed to vomit every half hour until nothing is left, then I vomit nothing. Finally, someone shares some dramamine, which reduces my puking time frame to once every hour.

As of right now I haven't ralphed since lunchtime, and my stomach is accepting bread and rice, so I think I'm through the worst of it. Which is just as well, because mechanical issues have now reared their ugly heads and we have to steam back into port for some (hopefully) quick repairs. Which means we're going back through the weather.

This is balls-to-the-wall marine science, people. Stay tuned.

Bring Me That Horizon

2010-02-22T16:41:00.000-05:00

After a slight miscommunication that nearly kept me from getting through the gate (and I was afraid would get me shot or arrested... mostly shot) I have been aboard the Bigelow since about 9 this morning. We set off from sunny Newport, RI a little after 11, and are currently starting our way down to the Mid-Atlantic region (off the east coast of the U.S, not the Mid-Atlantic Ridge). I am currently typing this on the computer available in the quarters, but hope to talk to the proper channels about getting my laptop set up to work on the ship's network. Yes, I already have pretty pictures to share. Hopefully I can share them soon.

The Title of a Lonely Island Song

2010-02-19T20:26:00.000-05:00

After what can only be described as "hell week," I'm finally ready to embark on the biggest adventure in my grad school career (though I hear the AFS Tidewater meeting can get pretty raucous). Starting tomorrow I'll be heading up to my old stomping grounds in Rhode Island where I'll meet the NOAA R/V Henry Bigelow and it will become my home for nearly three weeks.

The Bigelow apparently maintains a satellite linkage for constant internet access. That means I'll be chiming in fairly regularly with updates on how the research is going/funny stories from the sea/pictures of badass marine life and/or shark puke. Oh yes, there will be pictures.

Until the next update, enjoy the NSFW celebration of my next three weeks below the jump.

One down...

2010-02-16T20:56:00.000-05:00

Thesis proposal defense: successful. Now the matter of this boat trip...

D-fence!

2010-02-15T22:49:00.000-05:00

So I've been talking a big game so far about spiny dogfish, shark/fisherman interactions, and my own research (and let's not forget the Sharktopus), but tomorrow is the first of many, many times I'll be forced to put my money where my mouth is. That's right, the thesis proposal defense is tomorrow, where I present everything I've been working on for the past semester and a half to a small crowd of my mentors and hope I haven't left any holes big enough to tear the whole project apart. After that, spiny dogfish and their stomach contents own me for the next year and a half (at least). Then I get to defend the whole thing.

But that's old news for most of the readers, as I'm pretty sure everyone who reads this blog is in grad school. Immediately following (and I do mean just about immediately) will be (hopefully) some inshore sampling and then I live on the Bigelow until just about the end of Spring Break. Don't worry, I'll be bringing a camera.

Update tomorrow, after I've either celebrated or drowned my sorrows.

"Awesome" is the Word You're Looking For

2010-02-13T12:36:00.000-05:00

DSN has taken to posting their Twitter posts daily on the blog, and this usually leads to some pretty entertaining finds (plus my first porbeagle post got a shout-out... I'm internet famous!). However, nothing I had seen previously could prepare me for this...

Yes, this is on my screen saver now. From io9.com.

Apparently the next great monster movie from SyFy will be titled simply "Sharktopus" and will feature, according to this article, something even stranger than the above concept painting.

This leads your humble author to speculate on whether this is the end result of cinematic tour-de-force "Mega Shark vs. Giant Octopus," which ended with (spoiler alert!) an apparent fight to the death between its two stars. I'm suggesting that perhaps the octopus and shark realized they had more in common than they thought, and after sinking out of sight, talked it out over some coffee, and, just maybe, fell in love...

More on Gulf of Maine Porbeagles

2010-02-10T23:25:00.000-05:00

Photo by Andy Murch.

First off, peace to Captain Phil.

Recently Underwater Times has linked to a couple more stories about the population of porbeagles interacting with fishermen in the Gulf of Maine. This whole story has some interesting parallels with the spiny dogfish situation, except in this case with a much larger shark with a much less controversial conservation status.

First off is the news that satellite tags have revealed the breeding grounds of the porbeagle. We can now add these sharks to the long list of species that utilize the Sargasso Sea for breeding. As Steve Campana points out, this is significant for the conservation of the species. As of right now the area is rarely fished and the sheer depth makes efficient fishing almost impossible. This gives porbeagles a serious advantage over other species that breed in estuaries, which can be crawling with human impacts, and may have a lot to do with the apparent resurgence of these sharks in the Gulf of Maine.

Hot on the heels of this research comes a strange consequence of scientist/fisherman cooperation. Steve Campana, the same researcher responsible for finding the porbeagle's breeding ground, is now speaking out against seafood bans in a local grocery chain. His argument is that such bans set a dangerous precedent that could eventually drive fishermen out of business. This may seem like a bizarre comment from a noted shark scientist and conservationist, but his reasoning is actually pretty sound. He argues that cooperation with fishermen is essential for good fisheries science.

As usual with fisheries issues, this is far from a black-and-white argument. On one hand you have a grocery chain that has decided to throw its considerable clout behind marine conservation efforts. Some conservationists argue that outright elimination of seafood is essential for preserving the marine environment, and would certainly find no fault with any vendor banning a type of seafood with as bad a conservation record as shark. In this case the seafood ban could potentially protect the very same porbeagles Dr. Campana studies.

On the other hand, cooperation between fishermen and scientists is essential to good marine science. Fishermen are out working on the water for days at a time on a regular basis, and notice trends and events that scientists just don't have the funding or resources to find on their own. At the same time, scientists bring their training and tools to the table when hard evidence and analysis on these trends and events are needed. The combination of the anecdotal observations of fishermen and the analytical skills of scientists can be a match made in heaven, it just requires good communication between the two parties (something that, unfortunately, isn't that common).

So in the process of speaking up for the fishermen he works with, Steve Campana may have opened himself up to criticism for being anti-conservation. I wouldn't be surprised if there was some fallout from this, and it'll be interesting to see how those chips fall.

Grad School Life

2010-02-08T22:57:00.000-05:00

A little personal update for those of you keeping score at home.

Field work is heating up. In the next two weeks I'm either due to be on a week-long cruise (possibly with only a day's notice... weeeee...) or on a couple day trips for some inshore sampling. After that I'll be hopping on the NOAA R/V Henry Bigelow until mid-March. All while teaching and going to class. If nothing else, grad school really teaches you how to multitask.

This of course goes hand in hand with defending my thesis proposal, which will be fit in there somewhere.

At times like these it's important to stop and remember why you're trying to line all this stuff up. In my case it's because I'm about to be out on the high sees playing with small sharks. And that's pretty cool.

Start looking for field work-related posts soon.

Bait in the Water

2010-02-07T16:11:00.000-05:00

Both fishing and a lot of marine science are generally all about dropping some bait in the water and seeing what happens. Swiped from Climate Shifts by way of DSN, here's a selection of possible outcomes when you drop a baited camera in the waters off Australia.

My personal favorites: the hammerhead repeatedly smacking against the camera (I can just imagine it thinking "curse you, evolution!") and the repeated, and ultimately successful, attempts by a massive tiger shark at separating bait from camera (including the near-demise of a sea snake hanging out in the wrong place at the wrong time).

Enjoy, and go Saints.

The Trouble with Models

2010-02-05T20:15:00.000-05:00

Today I'm going to talk about something that has proven to be both a blessing and a curse to fisheries management. I'm going to talk about modeling.

Tasteful humor. From Sports Illustrated.

Unfortunately we're not talking about the merits of the 2010 Swimsuit Calender (and allow me to be the millionth or so ecology nerd to make this kind of joke). The models we're talking about look a lot more like this:

From mdsg.umd.edu

Though a network modeler might see a thing of beauty in the latter image, for most of us at first glance it looks like a set of stereo instructions gone horribly wrong. That said, the idea behind ecological modeling is actually a very simple one; you're basically just tracing the flow of energy through an ecosystem. Along the way it makes stops at each ecological component (also known as bacteria, plants, and animals, but can also include things like detritus) and at each stop some of it is burned off, some of it recycles back to lower levels of the food web (usually this means the organism dies and ends up in the detritus) and some of it moves along to the next stop. The actual units of energy measured can vary from model to model, but the basic concept is generally the same, at least when applied to ecology.

The problems start to arise with the sheer amount of information that has to go into these things. As you can probably imagine, any kind of accurate food web model has to have detailed data on feeding habits, metabolism, and life history for every single species within that system. Often this is impossible given the amount of data published or collected, the limitations of the current technology, and the maintenance of any semblance of sanity for the researchers involved. This requires certain abstractions to be built in and certain (sometimes huge) assumptions to be made. Because of this, as one of my professors once said, "all models are wrong, but they're useful."

Probably the biggest assumption that has to be made is that the model is dealing with a discrete, closed system. All the energy flowing in eventually equals all the energy flowing out. This is obviously impossible in reality because sooner or later all ecosystems connect to at least one other ecosystem. Some models try to get around this by having a certain amount of the energy being tracked bleed off into "export," but are often vague about where they get this number.

Another pitfall of the "closed system" approach comes from things like apex predators (you knew sharks were coming into this eventually). These animals have high enough energy needs that they usually feed out of several smaller systems. To include something like a sand tiger shark you'd need to either have a big enough ecosystem to encompass its whole range or figure out which fraction of its energy needs comes from eating out of your study area. Highly migratory species present this same kind of problem, and it's why in a lot of marine models the food web ends at predators like striped bass and bluefish, species that are high up on the food chain but not necessarily at the top.

Where things get interesting is when models are used to determine policy. Ask any fisherman and they'll give you an earful about the mysterious voodoo math that affects their ability to work. They've got a valid complaint, and most fisheries managers are well-aware that they are making decisions that directly affect peoples' lives based on a system that is "wrong, but useful." The arguments resulting from controversy over models can drive both fishermen and scientists completely nuts. Unfortunately, the sheer size and complexity of the marine environment makes this sort of thing necessary. The alternative is to continue managing one species a time, something that has arguably only made the fisheries situation worse.

One thing is certain, as long as there are models there will be a need for good, accurate, basic science to go into them. Modeling has the potential to be a great tool for solving problems that until recently were simply on too large a scale to tackle, but it needs to be fueled by the best available data. Only by having all that basic biological information on as many species as possible can models start to overcome their limitations. Those of you afraid that field work is slowly being replaced by computers can rest easy; there is plenty of net-hauling and fish-counting to do.

So that's my take on a rather dense and complex topic, and I fully acknowledge that it's the opinion of a mere Master's student just starting to get his field work off the ground. Am I on the money? Am I completely misunderstanding everything? Was this whole discussion just an excuse to put a picture of a hot girl on the blog?

Sharks from Home

2010-02-01T23:39:00.000-05:00

Short but sweet post today on some shark news from my old stomping grounds in New England, courtesy of Underwater Thrills.

First off, a short and breezy documentary on blue sharks off the coast of my home state of Rhode Island:

Snappa Charters has been running shark dives out of the Port of Galilee in Narragansett for decades. I remember seeing the shark cage on the back of their boat when I was a kid and wondering what it would be like to cage dive with some of the Atlantic's finest. One day...

To prove just how sharky the cool waters up North can be, here's another story about great whites marked with satellite tags off of Massachusetts. The first tag has popped up and Greg Skomal of the Mass DMF is going over the data. This first shark made it all the way to Florida, so it should be some interesting stuff.

And of course, no discussion of New England sharks would be complete without linking to Captain Tom's New England Sharks site. This site is a testament to the amount of knowledge that fishermen can provide on the marine ecosystem.

"Plague of Sharks" in the Gulf of Maine

2010-01-30T11:35:00.000-05:00

Gimme your fish and no one gets hurt. Photo by Andy Murch.

I found this story on Underwater Times and thought it was interesting given how deep into fisherman/shark relations any work with dogfish requires you to go. Apparently a new shark has begun to assert itself as one of the dominant pest species in the Gulf of Maine. This shark is the porbeagle (Lamna nasus) and the fact that it is now being put on the same level as the humble dogfish says a lot about the relationship between sharks and people and state of the Gulf of Maine fishery.

The porbeagle is most definitely not a dogfish. This is a large, highly predatory shark that is closely related to the great white and shortfin mako, two superstars of the shark world. Like all mackerel sharks it is capable of maintaining a body temperature above that of the surrounding water, making it well-adapted to the cold Gulf of Maine.

While the status of the spiny dogfish as an endangered species is under heavy debate, there is little debate that the porbeagle has suffered under overfishing, and has been for a while. The IUCN lists this shark as "Vulnerable" and as such it is subject to very low quotas in US fisheries. So what is causing this large, charismatic, endangered shark to be mentioned in the same breath as the reviled dogfish?

Apparently in the last three years they've made a bit of a comeback in the Northwest Atlantic and have started hitting the gillnets of Gulf of Maine fishermen. According to the above article, porbeagles are chasing off valuable fish, destroying gear, and stealing the catch faster than the fishermen can haul it out. As a result, fishermen are calling for higher quotas to thin the population. Sounds eerily familiar, doesn't it?

Unlike the dogfish debate, the "plague of porbeagles" does have a disturbing hint of shifting baselines to it. Here is a species that is still all but extinct in much of its European range and the IUCN estimates that the population off of Canada and New England is still only 30% of its virgin stock. Ordinarily the resurgence of a species in decline would be greeted as a triumph of management and conservation, but in this case it's a "plague."

The implications for this are pretty far-reaching when it comes to the intersection of ecology and sociology. I have neither the time or the expertise to do them proper justice, but I'll list a few possible scenarios as food for thought:

1- The fisheries of the Gulf of Maine have declined to a point where the return of a top predator, normally a sign of a healthy ecosystem, now represents direct competition with fishermen.

2- Sharks, whether they are spiny dogfish or porbeagles, are intelligent, highly adaptable animals that know how to take advantage of an easy meal, and the sheer amount of fishing occurring in New England has conditioned them to seek out fishing gear and feed out of it.

3- Due to the constantly fraying relations between fishermen and managers (some of which may be fueled by the dogfish debate), a short-term increase in porbeagle abundance is not seen as a sign of success, but as a sign of mismanagement.

In any case, these are interesting times for fishermen, managers and conservationists alike. As shark conservation becomes more serious (and potentially successful) it can be expected that this sort of debate will happen more often.

Any other interpretations out there?

My Research: the Cliff-Notes Version

2010-01-28T20:42:00.000-05:00

So now that I've introduced myself, defended the honor of the spiny dogfish, and posted some nice pictures, it's time to toss some science-in-progress into the mix. Eventually, I'm hoping to profile some of the projects being pursued by my lab-mates and friends, and I might as well take the lead with my own humble thesis. This is what will likely be defining my life for the next two years (at a minimum), barring any disasters during the proposal defense. Any brand new grad students reading should take heed; this is the level of work expected of you.

First off, some background. I'm doing my grad work at East Carolina University under the direction of Dr. Rulifson (whose spiny dogfish work can be seen at spinydogfish.org - check the Contact section for a certain handsome devil). I've been interested in sharks and shark research since I was but a wee lad, and as stated two posts down, I'm convinced that spiny dogfish are secretly some of the most interesting sharks out there. So here it is for your reading pleasure; the quick and dirty version of my thesis proposal. Keep in mind that this is written for a blog audience, so I've kept the technical aspects and scientific language to a minimum (I do have citations though). Since any good thesis lives or dies on feedback, questions and comments are encouraged.

Food and feeding of the spiny dogfish (Squalus acanthias) overwintering off the coast of North Carolina and the effects on the marine community

Introduction: Spiny dogfish have long had a reputation for being generally bad neighbors with fishermen, whether they're eating the catch, wrecking gear, or driving off other commercially-important species. This has lead to an interest among fishermen and scientists in the feeding habits and community interactions of these small sharks. Diet data is routinely collected by the NOAA/NMFS bottom trawl surveys, and this data has lead to a good pool of literature on the large-scale, ecosystem-wide feeding habits of dogfish (Bowman et al. 2000, Link et al. 2002). However, the sheer scope of this work has potentially had the effect of overshadowing localized short-term feeding events such as seasonal migrations and spawning runs, and the amount of predation going on during these events can be significant (Beamish et al. 1992).

Another aspect of dogfish migrations is that the sharks occupy the same feeding guilds as many of the other, similar-sized predatory fish that are targeted by both commercial and recreational fishermen (Garrison and Link 2000). This means that spiny dogfish potentially compete for food with a lot of the fish we like to eat, including striped bass, bluefish, cod, and flounder. It has long been suspected that the aggressiveness and sheer numbers of large migrating schools of dogfish have the effect of driving out other, more desirable species.

A large chunk of the dogfish population makes a seasonal migration south from New England for the winter, coming to a stop off of North Carolina (McMillan and Morse 1999). The purpose of my project is to provide data on two aspects of the large seasonal presence of spiny dogfish in North Carolina waters; feeding habits and the effect of dogfish presence on the relative abundance of other species in the area.

Methods: I'll break these up by the two main objectives of my study. Sampling of dogfish will be performed opportunistically aboard research trawl surveys passing through North Carolina waters during the months of January-March. I'm already due to be on the NOAA R/V Henry Bigelow (trip blogging, anyone?) when it comes through North Carolina waters, and am constantly in the process of getting extra trawl sampling in. I'm sampling by trawl because this seems to be the "least worst" method for getting stomach content data (hook and line sampling selects for hungry fish with empty stomachs, while the stress of capture in gillnets tends to cause dogfish to puke before being hauled aboard).

Feeding Habits: I'll be sampling dogfish stomach contents non-lethally using the stomach tube gastric lavage method (I'll be giving this awesomely gross method the full post it deserves at a later date). The gut contents will be preserved and brought back to the lab, where they will be identified as close to species level as possible. Hopefully enough of the stomach contents will be relatively intact to get accurate counts and weights, but at the very least I should be able to get presence/absence for any given prey category. If enough quantitative data is available, I'll figure out the overwinter consumption rate and compare it with fishery landings of prey species in North Carolina to see just how big a chunk dogfish may be eating out of the stocks. Also, the lavaged dogfish will be divided into groups based on size and sex to assess the affect of growth and sex on the diet.

Community Interaction: While on the trawl surveys I'll be taking down relative abundance data for all the trawls made within North Carolina waters and comparing the species composition in trawls containing dogfish with those lacking the marauding sharks. This is to see if the mere presence of dogfish may be altering the distribution of other species in the North Carolina marine community.

Expected Results: Right now all I've got for expected results is basically what the literature and common sense would suggest; prey species will probably be the most common forage fish available and will co-occur with dogfish often, while other predatory fish will likely show a low co-occurrence with them.

So that's the talking-points version of what I'll be putting my sweat, blood, heart, and soul into during my graduate career. As of right now the proposal defense is being put together and the committee is being summoned, and so far I've gotten reasonably positive feedback. I'll be updating my progress as progress is made, so stay tuned. By this time next month I should be knee-deep in dogfish puke.

Sources Cited and Further Reading

Beamish, R.J., B.L. Thompson, and G.A. McFarlane. 1992. Spiny dogfish predation on chinook and coho salmon and the potential effects on hatchery-produced salmon. Transactions of the American Fisheries Society 121:444-455.

Bowman, R.E., C.E. Stillwell, W.L. Micheals, and M.D. Grosslein. 2000. Food of Northwest Atlantic fishes and two common species of squid. NMFS-NE 155, 138p.

Garrison, L.P. and J.S. Link. 2000. Dietary guild structure of the fish community in the Northeast United States continental shelf ecosystem. Marine Ecology Progress Series 202:231-240.

Link, J.S., L.P. Garrison, and F.P. Almeida. 2002. Ecological interactions between elasmobranchs and groundfish on the Northeastern U.S. continental shelf. 1. Evaluating predation. North American Journal of Fisheries Management 22:550-562.

McMillan, D.G. and W.W. Morse. 1999. Essential fish habitat source document: Spiny dogfish Squalus acanthias, life history and habitat characteristics. NMFS-NE 150, pp. 1-3.

Sharks on the Web: Elasmodiver

2010-01-26T21:55:00.000-05:00

The better to eat you with... Photo by Andy Murch

After the previous post's lengthy manifesto, tonight I'll just point you in the direction of a really awesome shark-related website. I've been a fan of Andy Murch's work at Elasmodiver for years; his amazing photographs of sharks have been a fixture of my screen saver and powerpoints (all credited). The dogfish photo lurking behind the title of this very blog is his work. Andy's latest project is the Predators in Peril exhibition, a collection of conservation-themed shark photography. Unfortunately this seems to be happening exclusively on the west coast for now, but hopefully it makes its way east at some point. Until then, check out Andy's website for some of the best undersea photography on the internet, and for a very useful and accurate field guide to sharks and rays. A few of my favorites below the jump...

All photos by Andy Murch.

This just seems like a buddy comedy in the making.

Prionace glauca

Isurus oxyrinchus

Mustelus sinusmexicanus

Squalus acanthias

A gillnetter's worst nightmare.

Hope you've enjoyed the lighter fare today. For those of you craving more raw science, that's on its way soon, trust me...

In Defense of the Spiny Dogfish

2010-01-26T00:33:00.000-05:00

"Voracious beyond belief, dogfish deserve their bad reputation among many fishermen." - Bigelow and Schroeder's Fishes of the Gulf of Maine

As anyone with any kind of familiarity with Squalus acanthias will tell you, these are deeply unpopular animals. Fishermen have cursed the name "dogfish" for almost as long as commercial fishing has existed, and recent efforts at dogfish management have not made them any more sympathetic. Despite evidence of overfishing, these small sharks are still capable of turning up in massive numbers, swamping and damaging fishing gear, and devouring the catch. They lack the nobility of many of their shark cousins; you're not likely to see them making majestic leaps like great whites and makos, and they haven't earned the respect of sport fishermen like porbeagles or thresher sharks. For these reasons conservation of the spiny dogfish has been contentious at best.

So why would anyone in their right mind want to study these fish except to try and find ways of eradicating them? I make no secret that I fall on the side of conservation when it comes to this issue (though I want to see management of these sharks done right, but that's for another post). Hopefully this post will illustrate some of the reasons I think spiny dogfish deserve at least a little respect.

Face it, these are pretty impressive animals. They don't do tricks, they don't use tools, they're a pain in the butt to get out of a gillnet, but spiny dogfish exhibit a lot of interesting behaviors that are well worth study and, in my opinion, make them fairly charismatic. For one thing, those huge aggregations that can ruin a perfectly good day of fishing are fairly unprecedented in most species of sharks. Here is a shark that is highly social and has been virtually untapped in terms of animal behavior studies (most likely due to the difficulty in observing a fast-moving highly migratory school of fish in any detail). They segregate by size and sex, but why? The answers to this are still unclear. These sharks appear worldwide in all kinds of environments. How are they getting there? How far are they migrating? How is it that a fish that takes 12 years to mature and has a two-year gestation period is able to appear in large enough numbers to saturate fishing gear?

What has been studied in some detail is their feeding behavior, which, as the quote from Bigelow and Schroeder suggests, can be pretty hard to hyperbolize. These little sharks are highly adaptable, appearing en masse around sources of food that may only exist for a matter of days. A study by Beamish et al. (1992) showed that spiny dogfish in the Strait of Georgia would appear within the week that salmon hatcheries would release their smolts into the rivers. These inexperienced young salmon would venture out into salt water and immediately be pounced upon by up to 1.4 million hungry dogfish, just waiting for prey that had never seen a predator before. One year this veritable sea of sharks devoured nearly every smolt released by the Big Qualicum River hatchery, a release that represented 7.7 million smolts. Horrifying if you run a salmon hatchery, but downright awe-inspiring for a shark fan. Add to that evidence of pack-hunting (!) and you have a fish that has become a powerful and highly influential predator despite its relative lack of size or showiness. Basically, you have a shark that acts like a piranha, and there is no way that is not impressive.

Another interesting thing about spiny dogfish is that they be an example of evolution in action in a very long-lived, slow-growing species. Atlantic dogfish are a fairly k-selected species by any standard, with females only maturing after 12 years and a total lifespan of 40-50 years. However, in the Pacific the same species has a life history nearly identical to that of a human (except for that nasty two-year pregnancy), living up to 80-100 years! There is no doubt that the Atlantic and Pacific populations are reproductively isolated, since they have the small matter of the entire continent of North America between them. Is speciation occurring in spiny dogfish, or has it already happened?

Dogfish act as models for other sharks. Much of what we currently know about shark behavior, physiology, and hydrodynamics comes from studies on spiny dogfish. Thanks to their relatively small size, abundance, and ease of handling, this species is about as close as any shark gets to being a lab rat. Dogfish have been poked, prodded, dissected, run through flow tanks, and even had transmitters implanted in their brains so the Navy can use them as sea-going spies. Research on spiny dogfish has lead to developments in such disparate fields as submarine design and swimsuit materials.

One further way that spiny dogfish can act as models for their larger, more charismatic kin is in fisheries management. Much of the controversy and conjecture in spiny dogfish management comes form the fact that sharks are unlike any other fish that is managed. They are invariably slow-growing, late-maturing, and produce few offspring, meaning that once a shark stock is overfished it may take decades to recover, and may never recover at all. Most historical attempts at establishing a commercial shark fishery have resulted in a "boom and bust" progression as the population of the target species suddenly collapses. With dogfish we may or may not have hit the "bust" period (I'll leave the flak-catching for making that call to others more informed than I) but there may be an opportunity to manage the species before it sees the kind of massive population declines that have afflicted larger sharks. Dogfish management has had more than its share of growing pains, but if scientists, fishermen, and managers can get it right, then it may be possible to responsibly manage other shark species and figure out a way to recover those species that have already been hit hard by overfishing. But maybe that's just my idealistic take on the subject.

Dogfish just may end up being important. Marine biology and fisheries management are fraught with cautionary tales. Overfishing and irresponsible management have lead to all manner of unintended consequences. The increased abundance of spiny dogfish and other "mesopredator" elasmobranchs could be the result of two fishing-related problems. The first is competitive release due to the removal of the large predatory fish that used to compete with them for food, such as the case with Atlantic cod on Georges Bank. The other is the removal of the larger sharks that used to prey upon them. While the latter has yet to be positively proven with regards to spiny dogfish, it has been cited as the cause for the rapid increase in cow-nosed rays in the estuaries of North Carolina. Without the big hammerheads and tiger sharks to keep them in check, these rays now run rampant on their shellfish prey and may be responsible for the crash of the North Carolina bay scallop fishery.

The point here is that today's pest species may turn out to be much more important tomorrow. It was once considered that the only good shark was a dead shark, but now that there aren't as many policing the ocean it has become clear just how important a healthy stock of these "man-eaters" is to putting seafood on the plate. While it is extremely unlikely that roving packs of dogfish will ever menace bathers, these sharks also have quite an image problem. A species doesn't exert as much influence over the marine food web as the spiny dogfish without being important to the overall health of the ecosystem. It's already known that dogfish prey upon ctenophores (better known as comb jellies), which can be voracious predators of fish larvae. Would a crash in dogfish populations lead to lower reproductive success for other fish? Sound management of a species requires thorough knowledge of how that species fits into the big puzzle that is the marine ecosystem.

So that's my turn on the soapbox. I don't expect anyone who reads this to turn into a raging dogfish conservationist, but I do hope that it at least encourages deeper thought about that little shark that just stole your bait.

Sources cited and further reading.

Beamish, R.J., B.L. Thomson, and G.A. McFarlane. 1992. Spiny dogfish predation on chinook and coho salmon and the potential effects on hatchery-produced salmon. Transactions of the American Fisheries Society 121:444-455.

Camhi, M., S. Fowler, J. Musick, A. Brautigam, and S. Fordham. 1998. Sharks and their relatives: ecology and conservation. Occasional Paper of the IUCN Species Survival Commission 20.

Fogarty, F.J. and S.A. Murawski. 1998. Large-scale disturbance and the structure of marine systems: fishery impacts on Georges Bank. Ecological Applications 6:8-22.

Wallace, S.S., G.A. McFarlane, S.E. Campana, and J.R. King. 2009. Status of spiny dogfish in Atlantic and Pacific Canada. Pages 313-334 in V.F. Gallucci, G.A. McFarlane, and G.G. Bargman, editors. Biology and management of dogfish sharks. American Fisheries Society, Bethesda, Maryland.

Outreach!

2010-01-24T20:36:00.000-05:00

And "Ya Like Dags?" is born.

I'm Chuck, a grad student in North Carolina working on a study of spiny dogfish feeding habits and community interactions. I figured that since I'm doing some work that some might find interesting, and because I've spent a good chunk of my online time reading blogs about marine science (Deep Sea News and Southern Fried Science have been inspirations), I'd throw my hat into the blogging ring. I'm hoping to use this blog as a source of outreach for my research and hope to get some of my fellow researchers to chime in about theirs (some of which is much more interesting than mine). I'll also be writing about marine science news and other interesting research that I happen across, and since this is the internet, there will probably be a fair amount of YouTube videos and other goofiness as well. There will be an overarching theme of dogfish, sharks, fisheries, and marine science.

As to origins of this blog's ridiculous title, it comes partially from a line in the excellent Guy Ritchie movie Snatch, and partially from a fishing trip. My friends and I were out fishing off of Rhode Island and ran into a big school of spiny dogfish. Thinking it was witty, I asked my fishing buddies if they "liked dags" as I pulled one up. Somehow, it caught on to the point where we no longer call these little sharks dogfish, we just call them "dags." Since I'm now researching these animals, i guess my answer to this blog's title is "yes, I like dags."