Spiny dogfish sharks have had a complicated history when it comes to fisheries management, going from hated pest to crashed fishery to conservation concern and now one of two certified-sustainable shark fisheries ever (the other is the Pacific species of spiny dogfish). The story didn’t end with being certified sustainable though, and recently this fishery has been in the awkward position of keeping itself sustainable while also making sure fishermen can actually sell their catch. Dogfish quotas have been leaping up annually since the Atlantic fishery was first considered for MSC certification, much to the chagrin of conservationists who would prefer the management plan pay more attention to the life history of these small but slow-growing sharks. However, these increased quotas, combined with weakening demand in Europe as a result of the economic downturn, have lead to a massive surplus of dogfish in the U.S. market and dramatically lowered the price fishermen receive at the fish house. Meanwhile, seafood chefs are attempting to get consumers to try out species they’ve previously overlooked (mainly because many of their former favorites are severely depleted), with dogfish sharks among the former “trash fish.” While this movement gains momentum, fishing industry groups and 19 Senators and House Reps from coastal fishing states are exploring a different option, one that may put spiny dogfish in your local school lunch.
A lot of debate among conservationists centers on the conflict between the desire to see a species totally protected from human exploitation and the reality that market forces will continue to exist (see the latest on shark fin bans for a very good example). Ideally, a conservation plan should strike a balance, ensuring the continued existence of the species while still allowing people to profit from it in some way. This also requires a clear idea of the limitations of conservation policies. For example, US policies (even the mighty Endangered Species Act) only directly affect populations within the territorial waters of the United States, while international agreements like CITES restrict trade of the species without telling any particular country what to do domestically. However, there are ways to track the interaction between conservation policies and the market, making it possible to make some predictions on how things like fishery management plans and CITES listings might affect trade. Then it gets interesting. Armed with this knowledge, can the market be pushed towards species conservation?
I particularly like that they go into enough detail to lay out options for incorporating predation into fisheries. Personally, I’m a big fan of the “second fleet” option, in which predators are counted as another source of fishing mortality (and some of my favorite papers are cited in support of it). It does require the most effort, but provides the most accurate estimations of predation mortality (and justifies funding for diet studies? Please?). Multi-species models are ideal, and really the only way to conclusively prove that trophic cascades are actually happening. Precautionary buffers, in my opinion, should really follow thorough diet studies, but are certainly another important aspect of ecosystem-based management.
It’s neat to finally see this subject getting some attention. Here’s hoping the word continues to get out about the importance of shark puke.
It’s not every day that catching up on scientific literature causes you to almost do a spit-take on your laptop screen. This happened to me recently due to the weird and wild world of aquaculture. Aquaculture is the practice of growing aquatic animals such as fish and shellfish for the purpose of food, and has been held up as both a savior and destroyer of the marine ecosystem. To get an idea of what this generally looks like (at least here in the U.S.), Amy has a whole series of posts on aquaculture operations in North Carolina.
As with land-based farming, aquaculturists are motivated to find ways to increase the food value of their stock. The methods used are varied, from high-protein feed mixes to genetic manipulation. Recently, farmed salmon genetically-modified to grow larger and faster than their wild conspecifics have been approved for human consumption by the FDA, though not without debate. This man-made subspecies was created by modifying the already-existing DNA of the fish, but what if it turned out that simply injecting DNA from a different species could improve the growth and protein output of farmed fish? And what if that foreign DNA came from sharks?