Just a quick dogfish fishery news post for your Friday afternoon. NMFS has released the spiny dogfish quota for the 2012 fishing season, and as expected the quota has gone up. This year (starting May 1st) the dogfish quota will be set at 35.694 million lbs, with daily trip limits remaining the same as last year at 3,000 lbs. The rationale is that raising the quota while maintaining the status quo for daily trip limits will allow for a fishing season that doesn’t close as ridiculously quickly as last year’s. The agency’s scientists do caution that a dip in dogfish population is expected starting in 2014, because the dogfish reaching maturity then will be the offspring of the extreme low-recruitment years in the late 90s-early 2000s. If this increased quota manages to not crash the stock, it will bode well for the fishery’s bid (and very possible approval) for Marine Stewardship Council sustainability certification.
This has all been made possible by a sudden and seemingly unrealistic increase in dogfish biomass in the late 2000s. One interesting theory for how this may have happened was presented at the AFS Southern Division Meeting (unfortunately, I couldn’t make it this year) by Ryan Knotek (check out the podcast of his talk). Basically, not all spiny dogfish are breeding at the same time, which may have staggered the reproductive output of the species and helped mitigate the effects of overfishing. It’s one of many shark talks (and other worthwhile fisheries science talks) available on SDAFS’ podcast page.
During a literature search for some dissertation-related stuff I stumbled upon quite possibly the most awesome paper ever for a shark fan. It’s well-known that sharks, especially large, migratory species, supplement their diet of fish and sea mammals by scavenging on whale carcasses. It’s been theorized that whale carcasses are a very important food source for migrating sharks, but it seems like a relatively unreliable food scource: most large sharks don’t hunt cooperatively and even a 20-foot great white is highly unlikely to take down a 40-foot whale, so the sharks have to wait for something else to kill the whale. Or not. Apparently some sharks have taken matters into their own jaws and rather than waiting for whale carcasses, they create them.
Way to totally overshadow my post about makos, guys.
In case you haven’t been following, filmmaker and ocean enthusiast (seriously, have you seen The Abyss?) James Cameron has made it to the Challenger Deep, also known as the bottom of the Marianas Trench, also known as the deepest point of the ocean on the planet. Congrats to James and the entire Deep Sea Challenge team. I can’t wait to see the footage and photos of what they see down there (first tangible evidence of Cthulhu?).
You might think that the title of this post refers to the spiny dogfish (Squalus acanthias), the main species of interest for this blog. You’d be wrong. You’d also be wrong to guess the great white, as badass a shark as that is. This post is dedicated to a shark that, despite its relatively average size (by large shark standards), makes its living eating prey that are themselves infamous for being voracious predators. This post is dedicated to the velociraptor of the sea, the shortfin mako (Isurus oxyrinchus).
It should be no secret to readers of this blog or anyone familiar with fisheries at all that spiny dogfish have a pretty rotten reputation among commercial fishermen. Quickly approaching the notoriety of dogfish are those damn dirty sea mammals, the harbor seals. Both animals have enjoyed recent increases in population: dogfish from a period of proactive fishery management, and seals from riding along on the Marine Mammal Protection Act. Arguments against protections for both of these species usually hinge on the alleged economic damage they do to fisheries by stealing the catch, destroying gear, and consuming commercially-important species. However, until recently there hasn’t been much concrete information on just how damaging these “pests” can be. A new paper by researchers working in the Cape Cod gillnet fishery attempts to answer that question, at least for New England groundfish.
The NC Maritime Museum, the venue for this year's Tidewater.
Last weekend I attended the 26th Annual Meeting of the Tidewater Chapter of the American Fisheries Society, better known as AFS Tidewater or just plain Tidewater. To recap, this conference encompasses fisheries academics, students, and managers from the so-called “tidewater region,” which is made up of the states of Delaware, Maryland, Virginia, and North Carolina. This chapter emphasizes marine and estuarine topics, which can be a welcome change from the larger, more freshwater-dominated meetings. This year the conference was in Beaufort, NC, which is well-covered by marine and fisheries research, with the NC State, UNC, and Duke marine labs, the main office of the NC Division of Marine Fisheries, and a good-sized NOAA lab all nearby. Beaufort is also rich in ocean-related history, and the venue (The NC Maritime Museum) reflected this well. As it turned out, the spring weather (mostly) broke out the day before the conference, making it a perfect time to be in Beaufort. So how’d it go this year?
Posted in AFS, conference, cownose rays, dorkiness, ecology, fisheries management, grad school, NOAA, North Carolina, spiny dogfish, striped bass
From tonight to Saturday afternoon I’ll be in beautiful sunny Beaufort, North Carolina for the 26th Annual Meeting of the AFS Tidewater Chapter. This is one of my favorite conferences every year and has the distinction of being my first academic conference. I’ve attended and recapped the 2010 and 2011 meetings, and will do the same for this year. Since Beaufort is the unofficial center of the marine science universe, I expect this to be even more fun than usual. If you’re in the area feel free to come out for some pints.
During my last trip out to the field, I documented a small shark that came up in the gillnet, and identified it as a juvenile blacktip shark. Now, after looking over the picture in better detail and consulting the literature, I’m not so sure. I’m considering reclassifying the little guy, but I’m still not 100% on it. Fortunately, I count shark experts and experienced fishermen among my readers, so I’d like to take this opportunity to get feedback from you (yes, you!) on whether my species ID is sound. I want to get these kinks ironed out before I get my own dissertation project ramped up and (hopefully) start pulling up similar-looking Carcharhinids by the dozen. Read on for the pictures and particulars…
Sustainable practice? From spinydogfish.org (photo by Sara Miribilio)
This week the U.S. Atlantic spiny dogfish fishery took another step towards becoming the second shark or ray fishery ever to earn a sustainability certification from the Marine Stewardship Council (MSC). The first was the Pacific spiny dogfish fishery, which turned out to be a decent call due to the fact that it would have very tightly controlled quotas and consist purely of hook-and-line vessels. The Atlantic fishery, in contrast, encompasses all three fishing methods typically used to target groundfish on the U.S. East Coast. Since my Master’s thesis focused on this population, the Northwest Atlantic spiny dogfish stock is near and dear to my heart, and I’ve been following this story as it’s progressed. Earlier this week, MSC released the public comment draft report (available for your perusal here) of their assessment of the fishery. I’ll spoil the ending for you: at this stage, MSC concludes that the U.S. Atlantic dogfishery meets the criteria to be certified as sustainable. This is an interesting and somewhat surprising result for reasons involving both the dogfish themselves and the potential for bycatch.
After most of a semester in the office, I finally managed to get out on the water this past weekend. I traveled down to Hatteras with Andrea to help out with the latest piece of his project tracking different life stages of spiny dogfish. He managed to get his quota of adult males and females during the Rulifson lab‘s trips up to Cape Cod, but his mission this winter is to implant acoustic transmitters into juvenile-sized dags to get a better understanding of where the little guys go. Of course I also had an ulterior motive: Andrea had told me about all the other sharks they had encountered while chasing dogfish the week before, and I wanted to get a look at them. The catch is that it’s been as freakish a winter in North Carolina as it has everywhere, especially off of Cape Hatteras, which in normal conditions is a huge mixing area of for coldwater species from the north and subtropical species from the south. Anything you can catch from Cape Cod to Cape Canaveral can and will show up at Cape Hatteras.