tag:blogger.com,1999:blog-31247534891974092632024-02-02T02:27:18.146-05:00Ya Like Dags?Spiny dogfish, grad school, and lifeChuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.comBlogger65125tag:blogger.com,1999:blog-3124753489197409263.post-57041005548184477892010-07-14T20:28:00.002-04:002010-07-14T20:31:05.426-04:00Selling OutSo 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 <a href="http://gam.southernfriedscience.com/">Southern Fried Science network</a>. 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 <i>too</i> large). So yes, you can think of it as selling out, but selling out to an indie label.<br />
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The blog can now be seen at <a href="http://www.yalikedags.southernfriedscience.com/">www.yalikedags.southernfriedscience.com</a>. 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.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-18262502925917435142010-07-14T14:11:00.000-04:002010-07-14T14:11:30.819-04:00AES Conclusions and An AnnouncementBelow 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.<br />
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-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 <i>Squalus acanthias </i>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.<br />
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-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.<br />
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-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.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-51796533414278126402010-07-11T11:58:00.000-04:002010-07-11T11:58:46.000-04:00AES Day 3.5Day 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...<br />
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-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 <a href="http://www.southernfriedscience.com/">David Shiffman</a> 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. <br />
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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.<br />
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-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<a href="http://yalikedogfish.blogspot.com/2010/04/man-vs-squid-your-salmon-need-you.html"> Humboldt squid</a>. Suck on that, squid fans.<br />
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-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. <br />
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-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. Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com1tag:blogger.com,1999:blog-3124753489197409263.post-52354279891043066662010-07-10T18:39:00.002-04:002010-07-10T18:39:44.794-04:00AES Day 3 coming upI 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...Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-59113814877737337052010-07-09T19:06:00.000-04:002010-07-09T19:06:05.538-04:00AES Day 2 - Day of the DogfishToday 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.<br />
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-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.<br />
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-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.<br />
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-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.<br />
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-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.<br />
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-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." <br />
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-Occasional shark blogger <a href="http://save-our-sharks.blogspot.com/">Lyndell</a> 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.<br />
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Now I'm off to the AES student social, then tomorrow the first feeding symposium. Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-6495304557710365622010-07-08T22:08:00.002-04:002010-07-09T19:09:31.930-04:00AES Day 1The 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.<br />
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-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 <a href="http://www.southernfriedscience.com/">David</a> 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.<br />
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-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 <i>Carcharodon carcharias</i> 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.<br />
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-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.<br />
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That concludes Day 1 of the AES coverage. Tomorrow <a href="http://save-our-sharks.blogspot.com/">Lyndell</a> and I give poster talks, and <a href="http://www.spinydogfish.org/">Jen</a> from my lab talks about what she's been up to with her work stalking spiny dogfish.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-69273548290986961022010-07-05T22:39:00.000-04:002010-07-05T22:39:24.573-04:00Dogfish on Tour: The Providence PreludeYour 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 <a href="http://www.dce.k-state.edu/conf/jointmeeting/">Joint Meeting of Ichthyologists and Herpetologists</a> 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.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-11471331049436961032010-06-29T21:55:00.002-04:002010-06-30T00:46:12.542-04:00The Ya Like Dags? Social Guide to Rhode IslandTwo posts in two days? It's like I'm a real blogger all the sudden.<br />
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The occasion for this post is that next week I'll be participating in the <a href="http://www.dce.k-state.edu/conf/jointmeeting/">Joint Meeting of Ichthyologists and Herpetologists</a>. 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 <a href="http://elasmo.org/">American Elasmobranch Society</a> 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.<br />
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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.<br />
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<b>In Providence</b><br />
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.<br />
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<i>Places to drink</i>: 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. <b>The Trinity Brewhouse</b> 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 <b>Union Station Brewery</b> 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 <b>The Wild Colonial</b>, 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 <b>Wickenden Pub</b>, which has an absurd number of beers available, and is prone to combining them with tasty results.<br />
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<i>Non-drinking activities</i>: 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 <b>AS220</b>, 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 <b>Lupo's</b>. If architecture and history are your things, you'll want to take a walk around pretty much the entire <b>College Hill</b> area, which is home to Brown University and the Rhode Island School of Design (<i>Family Guy </i>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 <a href="http://en.wikipedia.org/wiki/H._P._Lovecraft">H.P. Lovecraft</a>). For people watching, you can't beat <b>Thayer Street</b>, 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.<br />
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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.<br />
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<b>Outside Providence</b><br />
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.<br />
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<b>The Mews Tavern</b>: 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, <i>do it</i>.<br />
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<b>The Ocean Mist</b>: 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.<br />
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<b>Boon Street Eateries</b>: 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. <br />
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<b>Narragansett Beach</b>: 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.<br />
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<b>Brickley's</b>: 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.<br />
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<b>Newport</b>: 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.<br />
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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.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com2tag:blogger.com,1999:blog-3124753489197409263.post-59140232973803158152010-06-28T19:16:00.001-04:002010-06-28T19:17:34.309-04:00First New England Great White of 2010I'm headed back up to my motherland of Rhode Island next week for the <a href="http://www.dce.k-state.edu/conf/jointmeeting/">Joint Meeting of Icthyologists and Herpetologists</a> (mainly because of the heavy <a href="http://elasmo.org/">AES</a> presence there), and it seems the great whites are going to be there to greet me. The <a href="http://newsblog.projo.com/2010/06/great-white-shark-spotted-off.html">first New England great white of the summer</a> has surfaced off of Boston, where it was caught, tagged, and released by a group of Gloucester fishermen. The Dorsal Fin has a looped <a href="http://www.thedorsalfin.com/shark-news-stories/great-white-shark-tagged-off-massachusetts/">video</a> of the shark taken by the fishermen. Maybe I should bring my snorkeling gear with me...Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-22845997956203976682010-06-24T20:37:00.000-04:002010-06-24T20:37:47.885-04:00Feeding Habits Analysis: Detective Work Part 2In my previous post on <a href="http://yalikedogfish.blogspot.com/2010/06/feeding-habits-analysis-detective-work.html">the detective work necessary</a> 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.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzuyZYjJQ3cbSRgPnI523RMtaxdomv62DOW8vF_voNVaT1gXR3HoEWePTpuQZWz7TXpqSdD82iQGGxzkOp3yUvhyphenhyphenLgjWIbQZVOXD4DML9rxFcdiHuiZitjd5QpeUfl7BB84FhpoIXScrA/s1600/menhaden+type+2+%26+3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzuyZYjJQ3cbSRgPnI523RMtaxdomv62DOW8vF_voNVaT1gXR3HoEWePTpuQZWz7TXpqSdD82iQGGxzkOp3yUvhyphenhyphenLgjWIbQZVOXD4DML9rxFcdiHuiZitjd5QpeUfl7BB84FhpoIXScrA/s320/menhaden+type+2+%26+3.jpg" /></a></div><div style="text-align: center;">Atlantic menhaden (<i>Brevoortia tyrannus</i>). I've posted before on <a href="http://yalikedogfish.blogspot.com/2010/05/feeding-habits-analysis-tasty-menhaden.html">how tasty these ubiquitous cuplieds seem to be</a> 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.</div><div style="text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNeYZ_9rFJ0JDNIIR-Yc5jsiC_ebFwpYwzgoeK5WMRQWlmrRkfBlnPy7x2oI4mYvCU6xWPv9PlpiijUwaXqvxc70sIct3NKo0acBlMNEouHs2nMzol8aKREzO1rupOtkfs_68Z-3jPqHo/s1600/bay+anchovy+type+1+%26+2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNeYZ_9rFJ0JDNIIR-Yc5jsiC_ebFwpYwzgoeK5WMRQWlmrRkfBlnPy7x2oI4mYvCU6xWPv9PlpiijUwaXqvxc70sIct3NKo0acBlMNEouHs2nMzol8aKREzO1rupOtkfs_68Z-3jPqHo/s320/bay+anchovy+type+1+%26+2.jpg" /></a></div><div style="text-align: center;">Bay anchovy (<i>Anchoa mitchilli</i>). These fish show up in the hundreds, usually intact. Dogfish must just swim through large schools oft these <a href="http://yalikedogfish.blogspot.com/2010/05/feeding-habits-analysis-pizza-toppings.html">would-be pizza toppings</a> 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.</div><div style="text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4lqqV3XBD7MJhS6amG1_XZSMt4KO1eTJJKpBckmvKcCRQUj4ZYf2m8SPeCMAHvjZKpQXbU-MIArJWgp_xKjSf8oGdD4mo44MY7bkjxEtq2wZKbJQN2Pzx0ngr2du_JRChGFk-4ye0ESY/s1600/croaker+type+1+%26+2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4lqqV3XBD7MJhS6amG1_XZSMt4KO1eTJJKpBckmvKcCRQUj4ZYf2m8SPeCMAHvjZKpQXbU-MIArJWgp_xKjSf8oGdD4mo44MY7bkjxEtq2wZKbJQN2Pzx0ngr2du_JRChGFk-4ye0ESY/s320/croaker+type+1+%26+2.jpg" /></a></div><div style="text-align: center;">Atlantic croaker (<i>Micropogonias undulatus</i>). 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. </div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-18579189417205748182010-06-20T20:32:00.000-04:002010-06-20T20:32:24.869-04:00Marine Rewilding?<span style="float: left; padding: 5px;"><a href="http://www.researchblogging.org/"><img alt="ResearchBlogging.org" src="http://www.researchblogging.org/public/citation_icons/rb2_large_gray.png" style="border: 0pt none;" /></a></span> <br />
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It's amazing what you'll catch in the letters to the editor sometimes. In the latest issue of <a href="http://www.fisheries.org/afs/publications_fisheries.html"><i>Fisheries</i></a> 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 <i>Fisheries</i> 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.<br />
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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.<br />
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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 <i>Homo sapiens </i>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.<br />
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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?<br />
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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.<br />
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<span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.jtitle=Fisheries&rft_id=info%3Adoi%2F10.1577%2F1548-8446-33.4.180&rfr_id=info%3Asid%2Fresearchblogging.org&rft.atitle=The+North+Atlantic+Ocean%3A+Need+for+Proactive+Management&rft.issn=0363-2415&rft.date=2008&rft.volume=33&rft.issue=4&rft.spage=180&rft.epage=185&rft.artnum=http%3A%2F%2Fafsjournals.org%2Fdoi%2Fabs%2F10.1577%2F1548-8446-33.4.180&rft.au=Briggs%2C+J.&rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CMarine+Biology">Briggs, J. (2008). The North Atlantic Ocean: Need for Proactive Management <span style="font-style: italic;">Fisheries, 33</span> (4), 180-185 DOI: <a href="http://dx.doi.org/10.1577/1548-8446-33.4.180" rev="review">10.1577/1548-8446-33.4.180</a></span><br />
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<span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.jtitle=The+American+naturalist&rft_id=info%3Apmid%2F17080364&rfr_id=info%3Asid%2Fresearchblogging.org&rft.atitle=Pleistocene+rewilding%3A+an+optimistic+agenda+for+twenty-first+century+conservation.&rft.issn=0003-0147&rft.date=2006&rft.volume=168&rft.issue=5&rft.spage=660&rft.epage=81&rft.artnum=&rft.au=Josh+Donlan+C&rft.au=Berger+J&rft.au=Bock+CE&rft.au=Bock+JH&rft.au=Burney+DA&rft.au=Estes+JA&rft.au=Foreman+D&rft.au=Martin+PS&rft.au=Roemer+GW&rft.au=Smith+FA&rft.au=Soul%C3%A9+ME&rft.au=Greene+HW&rfe_dat=bpr3.included=1;bpr3.tags=Biology%2CMarine+Biology">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. <span style="font-style: italic;">The American naturalist, 168</span> (5), 660-81 PMID: <a href="http://www.ncbi.nlm.nih.gov/pubmed/17080364" rev="review">17080364</a></span>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com4tag:blogger.com,1999:blog-3124753489197409263.post-15061872729879350882010-06-14T23:26:00.000-04:002010-06-14T23:26:14.386-04:00Angry PostYou 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. <a href="http://www.deepseanews.com/">Deep Sea News</a> has been following the story from the beginning, and Southern Fried Science has a handy list of <a href="http://www.southernfriedscience.com/?page_id=5720">other places you can check</a> to follow the progress of the oil as it destroys the Gulf of Mexico and potentially the entire Atlantic coast. <br />
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Documents released today (or at least reported on today) reveal that <a href="http://www.msnbc.msn.com/id/37695879/ns/disaster_in_the_gulf/">BP knowingly and willingly cut corners</a> 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 <i>Deepwater Horizon'</i>s own chief engineer, who called the situation a "nightmare well." <br />
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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?Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-50484643469281740712010-06-08T22:48:00.000-04:002010-06-08T22:48:41.885-04:00Feeding Habits Analysis: Detective WorkAs 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.<br />
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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. <br />
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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.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7EyKBugLoMb8zutGcKo6grtmA8r6ox3_eeuiuPPg6YiKP8Z9rpJDCxeoUJO8CzrFtJ_DBS0pBCOX4WNbi1bjUIoriAY8V4XXaKuRUkgHw2VVMeEGdD8rDHIUaeIT632kNPaDLg0xk-NI/s1600/CH-25-08+scale+2+%26+3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7EyKBugLoMb8zutGcKo6grtmA8r6ox3_eeuiuPPg6YiKP8Z9rpJDCxeoUJO8CzrFtJ_DBS0pBCOX4WNbi1bjUIoriAY8V4XXaKuRUkgHw2VVMeEGdD8rDHIUaeIT632kNPaDLg0xk-NI/s320/CH-25-08+scale+2+%26+3.jpg" /></a></div><div style="text-align: center;"><i>If we were fish, eventually we'd all look something like this.</i></div><div style="text-align: center;"><br />
</div><div style="text-align: left;">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). </div><div style="text-align: left;"><br />
</div><div style="text-align: left;">What I need now (and what I'm hoping actually exists) is a nice taxonomic guide that covers scale and bone morphology. <a href="http://www.amazon.com/Bigelow-Schroeders-Fishes-Maine-Third/dp/1560989513"><i>Fishes of the Gulf of Maine</i></a> 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. <a href="http://www.fishbase.org/search.php">FishBase</a> 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. </div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com1tag:blogger.com,1999:blog-3124753489197409263.post-85138610099275584632010-06-06T21:40:00.000-04:002010-06-06T21:40:24.620-04:00New England Great Whites ReturnHere's an incredibly timely news item, given that my last post was a little <i>Carcharodon carcharias </i>humor and I'm watching "<a href="http://channel.nationalgeographic.com/series/expedition-great-white/all/Overview">Expedition Great White</a>" 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 <a href="http://www.capecodonline.com/apps/pbcs.dll/article?AID=/20100605/NEWS/6050325">at least one of the tagged sharks is on its way back</a> 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.<br />
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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.<br />
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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. Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-91001664197894443712010-06-04T20:36:00.000-04:002010-06-04T20:36:40.188-04:00New House, New Pet?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.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://media.theonion.com/images/articles/article/17544/shark_jpg_445x1000_upscale_q85.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://media.theonion.com/images/articles/article/17544/shark_jpg_445x1000_upscale_q85.jpg" width="250" /></a></div><div style="text-align: center;"><i>From <a href="http://www.theonion.com/">The Onion</a></i></div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-9419631008981212622010-06-02T21:25:00.001-04:002010-06-02T21:28:51.244-04:00Woo! 50th post!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. <br />
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<object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/9KP6e-JWrO8&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/9KP6e-JWrO8&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-72075928470194914392010-06-01T23:21:00.000-04:002010-06-01T23:21:52.759-04:00The Great Memorial Day Dogfish HuntEarlier I posted on <a href="http://yalikedogfish.blogspot.com/2010/05/spiny-dogfish-where-theyre-not-supposed.html">a population of spiny dogfish</a> 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 <a href="http://www.spinydogfish.org/">Dr. Rulifson</a>, 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...<br />
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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. <br />
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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.<br />
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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 <i>Squalus acanthias </i>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.<br />
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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.<br />
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For your viewing pleasure, here are a some choice photos from the trip.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivZMGNPB-Bcpi-QR9vr8auttvqoSMjngRiel-p_QQT4h9hFZJCunJsgK9_7ALlKv6S7ZjFrvKTt3nfpCnk1iJSmMOekMVWVk0R813vpseh_lhisdGeGNYA7OXKmDEdWrRkv1-_IV4AYZI/s1600/PICT1154.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivZMGNPB-Bcpi-QR9vr8auttvqoSMjngRiel-p_QQT4h9hFZJCunJsgK9_7ALlKv6S7ZjFrvKTt3nfpCnk1iJSmMOekMVWVk0R813vpseh_lhisdGeGNYA7OXKmDEdWrRkv1-_IV4AYZI/s320/PICT1154.jpg" /></a></div><div style="text-align: center;"><i>Cape Lookout Light. Our backdrop for most of the day.</i></div><div style="text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1jV9lmiGaBJDGZqZWXVpXe6knNfPP3TqLX9nqAHeQ3wHIx437tiV_Pf_oW0k4HGiB1u68oAmgIDHA72rqk5hC2_awS-O2_WBw2SJLTwi4RdL5MsTSZwzuBBDKjPeElJpygITG-8D4j3A/s1600/PICT1149.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1jV9lmiGaBJDGZqZWXVpXe6knNfPP3TqLX9nqAHeQ3wHIx437tiV_Pf_oW0k4HGiB1u68oAmgIDHA72rqk5hC2_awS-O2_WBw2SJLTwi4RdL5MsTSZwzuBBDKjPeElJpygITG-8D4j3A/s320/PICT1149.jpg" /></a></div><div style="text-align: center;"><i>Not a dogfish, but still a pretty good catch.</i></div><div style="text-align: center;"><br />
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</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvO9nuIrlq37nn6zYu47OUNMafO-WaLbDJOIbGyShyphenhyphenOpu7ESTVMKZpduIFYOYnLIXZP__1h1YD_2GuFZ0Cli2KOToOciEm9roFc-c5-X2wgInb7pr0mj5vKUvFDtaudLIq9YMSs8KwRjE/s1600/PICT1174.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvO9nuIrlq37nn6zYu47OUNMafO-WaLbDJOIbGyShyphenhyphenOpu7ESTVMKZpduIFYOYnLIXZP__1h1YD_2GuFZ0Cli2KOToOciEm9roFc-c5-X2wgInb7pr0mj5vKUvFDtaudLIq9YMSs8KwRjE/s320/PICT1174.JPG" /></a></div><div style="text-align: center;"><i>Spiny dogs, including Dan's first.</i></div><div style="text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwqiM4RKWN8bHOCEtwv5mhWf9lxoFX_18WEqN0DzFmVdqx1D0L-EL67dhkTpk35LavflBWIbqfAaUEwdA6bWtuzmIXvLLtRBrD4mka9lbsCWcCTrytl7lfpAP4DCLjBMgDHmT1ylObA5U/s1600/PICT1170.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwqiM4RKWN8bHOCEtwv5mhWf9lxoFX_18WEqN0DzFmVdqx1D0L-EL67dhkTpk35LavflBWIbqfAaUEwdA6bWtuzmIXvLLtRBrD4mka9lbsCWcCTrytl7lfpAP4DCLjBMgDHmT1ylObA5U/s320/PICT1170.jpg" /></a></div><div style="text-align: center;"><i>I got one! </i><i> </i><i> </i><i> </i><i> </i></div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-58736098928336113722010-05-25T23:17:00.000-04:002010-05-25T23:17:20.374-04:00DarWIN, not DarLOSE!I've always thought the comedic talents of both Dana Carvey and Charles Darwin were highly underrated.<br />
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<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" height="328" id="ordie_player_c550e56ad4" width="512"><param name="movie" value="http://player.ordienetworks.com/flash/fodplayer.swf" /><param name="flashvars" value="key=c550e56ad4" /><param name="allowfullscreen" value="true" /><param name="allowscriptaccess" value="always"></param><embed width="512" height="328" flashvars="key=c550e56ad4" allowfullscreen="true" allowscriptaccess="always" quality="high" src="http://player.ordienetworks.com/flash/fodplayer.swf" name="ordie_player_c550e56ad4" type="application/x-shockwave-flash"></embed></object><div style="font-size: x-small; margin-top: 0pt; text-align: left; width: 512px;"><a href="http://www.funnyordie.com/videos/c550e56ad4/dana-carvey-s-darwin" title="from JohnnyHoliday">Dana Carvey is "DARWIN"</a> - watch more <a href="http://www.funnyordie.com/" title="on Funny or Die">funny videos</a></div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com1tag:blogger.com,1999:blog-3124753489197409263.post-82516674205542307772010-05-23T17:27:00.000-04:002010-05-23T17:27:51.075-04:00Thoughts on North Carolina's Gill Net IssuesIt'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 <a href="http://obsentinel.womacknewspapers.com/articles/2010/05/19/top_stories/tops227.txt">management decisions have been made</a>. <br />
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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 <i>a lot </i>of local fishermen. <br />
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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 <a href="http://sports.espn.go.com/outdoors/fishing/news/story?id=4149657">surprisingly even-handed article from ESPN</a> (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.<br />
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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.<br />
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Which brings me to the second caveat: the presence of the <a href="http://www.joincca.org/">CCA</a> 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 <a href="http://www.southernfriedscience.com/?p=4411">got to the heart of the reasons why</a> 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.<br />
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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.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com1tag:blogger.com,1999:blog-3124753489197409263.post-4190754764220193582010-05-20T23:21:00.000-04:002010-05-20T23:21:17.656-04:00Feeding Habits Analysis: Pizza ToppingsIn 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 (<a href="http://yalikedogfish.blogspot.com/2010/05/feeding-habits-analysis-tasty-menhaden.html">or chunks of one of them</a>) to fill an average dogfish stomach. <br />
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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.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVXOcAbl7kfOOCzZpGju0UY9TdaLdVRtGf6TRf6mJJuR0O6FjjLHtH5Iq9ZKBnMKxwJgDS7IO_1-U8M4DUXnni8Iu82u3ZpComk5POws20iWAH-U_vA9NIXsyWDiROnFeTwsnocrOlu9Y/s1600/PICT1143.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVXOcAbl7kfOOCzZpGju0UY9TdaLdVRtGf6TRf6mJJuR0O6FjjLHtH5Iq9ZKBnMKxwJgDS7IO_1-U8M4DUXnni8Iu82u3ZpComk5POws20iWAH-U_vA9NIXsyWDiROnFeTwsnocrOlu9Y/s320/PICT1143.JPG" /></a></div><div style="text-align: center;"><i>There's too many of them!</i></div><div style="text-align: center;"><br />
</div><div style="text-align: left;">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 (<i>Anchoa mitchilli</i>). </div><div style="text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">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. </div><div class="separator" style="clear: both; text-align: left;"><br />
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</div><div class="separator" style="clear: both; text-align: left;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkyLbsnWtUd50ZCS2q_UzwtVBMO8QQQ4PyZAb2k18BuCSSY-NLyPms_bfbO8y0F6ZfLUVOQ0bqC5r_CN4wL36gIykskr3zagDUhj98AVlm4y2H-acmbTSDg51cta6oNvhWuAo6OPeOk3Q/s1600/PICT1146.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkyLbsnWtUd50ZCS2q_UzwtVBMO8QQQ4PyZAb2k18BuCSSY-NLyPms_bfbO8y0F6ZfLUVOQ0bqC5r_CN4wL36gIykskr3zagDUhj98AVlm4y2H-acmbTSDg51cta6oNvhWuAo6OPeOk3Q/s320/PICT1146.JPG" /></a></div><div class="separator" style="clear: both; text-align: center;"> <i>Apologies for the blurriness. One day I'll get a decent macro lens.</i></div><div class="separator" style="clear: both; text-align: center;"><i><br />
</i></div><div class="separator" style="clear: both; text-align: left;">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)<i> </i>that little bugger has several defining morphological features that provide tantalizing evidence that it is a blueback herring (<i>Alosa aestivalis</i>). 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 <a href="http://yalikedogfish.blogspot.com/2010/05/dogfish-where-theyre-really-not.html">swim up the river to get at it</a>). So the question is, what is this fish if it isn't a blueback herring? </div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;">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?</div><div class="separator" style="clear: both; text-align: left;"></div><div class="separator" style="clear: both; text-align: left;"></div><div class="separator" style="clear: both; text-align: left;"></div><div class="separator" style="clear: both; text-align: left;"></div><div style="text-align: left;"> </div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-47877944542612731512010-05-18T12:36:00.000-04:002010-05-18T12:36:07.182-04:00Dogfish Where They're Really Not Supposed to BeEarlier I posted about spiny dogfish <a href="http://yalikedogfish.blogspot.com/2010/05/spiny-dogfish-where-theyre-not-supposed.html">sticking around in parts of North Carolina</a> 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 <a href="http://www.kfvs12.com/Global/story.asp?S=12476372">swim up the river itself</a>.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://kfvs12.images.worldnow.com/images/12476372_BG2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="http://kfvs12.images.worldnow.com/images/12476372_BG2.jpg" width="320" /></a></div><div style="text-align: center;"><i>Far from home. From kfvs12.com.</i></div><div style="text-align: left;"><br />
</div><div style="text-align: left;">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<a href="http://www.wlwt.com/news/23552331/detail.html"> initially misidentified as a juvenile bull shark</a>, 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. </div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-77435002519605950672010-05-15T16:43:00.000-04:002010-05-15T16:46:17.601-04:00Dogfish Diets and the Influence of Holden<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHOkFkIxud3ccGH5ku9BIgjPE_JiNBy9LSAEVoZCC8bx4xL0xmRYMnmhz8ehOhjs0AzaFf-bM9x_dd6cTV-ISL3OByS3LTUdrS4xLi1U1GFO1faWwQPpLXQ7wSVnj8P4Cm7vGy-iPqPiw/s1600/Spiny+dogfish+105.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHOkFkIxud3ccGH5ku9BIgjPE_JiNBy9LSAEVoZCC8bx4xL0xmRYMnmhz8ehOhjs0AzaFf-bM9x_dd6cTV-ISL3OByS3LTUdrS4xLi1U1GFO1faWwQPpLXQ7wSVnj8P4Cm7vGy-iPqPiw/s320/Spiny+dogfish+105.jpg" /></a></div><div style="text-align: center;"><i>I can never get enough of this picture. Photo by <a href="http://www.elasmodiver.com/">Andy Murch</a>.</i></div><br />
As always, I have spiny dogfish and what they're eating on the brain, and the <a href="http://www.southernfriedscience.com/?p=5166">Menhaden of History</a> post over at Southern Fried Science and Kevin Z's <a href="http://deepseanews.com/2010/05/seeking-submissions-to-the-leviathans-shoulders/">challenge to the marine blogosphere</a> 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.<br />
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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. <br />
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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.<br />
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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. <br />
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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.<br />
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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. <br />
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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.<br />
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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).<br />
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<i>References</i><br />
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<div class="MsoNormal">Brett, J.R., and J.M. Blackburn, 1978. Metabolic Rate and Energy Expenditure of the Spiny Dogfish<i> Squalus acanthias</i>. Journal of the Fisheries Research Board of Canada 35:816-821. </div><div class="MsoNormal"><br />
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</style> </div><div class="MsoNormal">Hannan, K. 2009. Determination of gastric evacuation rate for immature spiny dogfish. Pages 253-258 <i>in </i>V.F. Gallucci, G.A. McFarlane, and G.G. Bargman, editors. Biology and management of dogfish sharks. American Fisheries Society, Bethesda, Maryland.</div><div class="MsoNormal"><br />
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</style> </div><div class="MsoNormal">Holden, M.J. 1966. The Food of the Spurdog <i>Squalus acanthias</i>. Journal du Consiel Perm. Int. Explor. Mer. 30: 255-266.</div><div class="MsoNormal"><br />
</div><div class="MsoNormal">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. </div> <br />
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</i>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-14831528084786749012010-05-13T21:56:00.000-04:002010-05-13T21:56:05.289-04:00Feeding Habits Analysis: Tasty Menhaden MorselsThis 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 <a href="http://www.southernfriedscience.com/?p=5166#more-5166">the Menhaden of History</a> 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."<br />
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If the mission of menhaden (of which the Atlantic species has the deceptively badass Latin name <i>Brevoortia tyrannus</i>) 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 <i>Squalus acanthias </i>can create can be found below the jump.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsLslMH950XSUKqfdgM_oXq36kDcc_3iprrx3gDnJ48sQvrKs1oQlkn3tIk8J3UUuK_1VhPnwNPu1k3YbsZ1KuMIif22JcPQNB_sOnyjpxu4vWvMUS3qMRGn_bhp8DLOINsyqnTyExAfU/s1600/menhaden+chunks.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsLslMH950XSUKqfdgM_oXq36kDcc_3iprrx3gDnJ48sQvrKs1oQlkn3tIk8J3UUuK_1VhPnwNPu1k3YbsZ1KuMIif22JcPQNB_sOnyjpxu4vWvMUS3qMRGn_bhp8DLOINsyqnTyExAfU/s320/menhaden+chunks.jpg" /></a></div><div style="text-align: center;"><i>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.</i></div><div style="text-align: center;"><br />
</div><div style="text-align: left;">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 <a href="http://www.youtube.com/watch?v=wYbBd4NAhuY">man-eating bluefish</a>). </div><div style="text-align: left;"><br />
</div><div style="text-align: left;">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 <i>awesome</i>.</div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com5tag:blogger.com,1999:blog-3124753489197409263.post-646367290848499932010-05-10T14:10:00.000-04:002010-05-10T14:10:07.516-04:00How the Oil Spill Affects FisheriesKevin Z over at Deep Sea News has <a href="http://deepseanews.com/2010/05/how-the-oil-spill-affects-fisheries-interview-with-dr-dave-kerstetter/">an interview with fisheries biologist Dave Kersetter</a> 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 <a href="http://deepseanews.com/">Deep Sea News</a>.Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com0tag:blogger.com,1999:blog-3124753489197409263.post-80071042628815023452010-05-08T16:53:00.000-04:002010-05-08T16:53:15.847-04:00Spiny Dogfish Where They're Not Supposed to BeIt'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. <br />
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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:<br />
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<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="http://www.dnr.state.md.us/fisheries/fishfacts/art/spiny_dogfish.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="97" src="http://www.dnr.state.md.us/fisheries/fishfacts/art/spiny_dogfish.jpg" width="320" /></a></div><div style="text-align: center;"><i>Image from Maryland DNR</i></div><div style="text-align: left;"><i> </i></div><div style="text-align: left;">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. </div><div style="text-align: left;"><br />
</div><div style="text-align: left;">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.</div><div style="text-align: left;"><br />
</div><div style="text-align: left;">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.</div>Chuckhttp://www.blogger.com/profile/01609288488696386212noreply@blogger.com3