AES Day 2 – Day of the Dogfish

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.