The only high-value market for shark products is fin, which is used in sharkfin soup sold in Asian markets.  Shark is also a directed catch for its fish oil and cartilage, sold to westerners who believe they have therapeutic value (there is no scientific validation of this). Shark meat (derived from tissues other than from fin) is eaten by some poorer coastal communities, but it is a very low value product, and not worth the space that it takes up in cargo holds of large commercial fishing vessels.

Bottom trawling is the most efficient way of catching demersal fisheries species, i.e. those living near the bottom. This includes what we in the Northern hemisphere call cod and haddock (genus Gadus).  When we talk of efficiency here, we mean maximum catch per unit effort, not minimum by-catch or disturbance however.

International treaties can go a long ways towards high seas sustainability and conservation, but only if it is matched with monitoring and enforcement.  Overfishing is a complex issue, however – in order to know what is a sustainable level of fishing, we must know more about stock size, dynamics, and so forth. The High Seas are relatively understudied. As for endangered species, international treaties already exist to protect them, whether they are within the territorial seas or EEZs of nations, or on the High Seas. But enforcement is a problem here again.

One way to affect change is to put international pressure on those few countries which are causing most of the fisheries-related High Seas problems.  These countries, and the corporations that underwrite large scale fishing (which are few in number), could be shamed and pressured through a variety of means, including consumer choice.  Special national sanctions could also be directed at countries which practice destructive High Seas fishing, similar to the Pelly Amendment in the US which allows the US to deny markets to products coming from countries that do not adhere to US environmental standards, such as requiring Turtle Excluder Devices in shrimp trawls.

Q: Is the most compelling issue overfishing or damage from poor fishing practices? - David K Vaughn

Many prominent conservationists and scientists have put forward analyses of trends in global fisheries (High Seas and continental shelf) suggesting both overfishing and a phenomenon called “fishing down the food web”, in which serial depletion of fisheries species begins at upper trophic levels (top predators) and moves down the food web.  Since upper trophic level species command much higher value in markets, many more lower trophic level species must be caught to turn a profit.  The fisheries techniques then increasingly approximate mining, as vast quantities of lower level organisms are taken.
But (and this is my (Agardy’s) opinion alone, a much greater problem with fisheries in general is not how much fisheries biomass is harvested, but how it is harvested. Destructive fishing threatens many important and sensitive habitats, such as deepwater corals, sea mounts, etc. At the same time, by-catch on the High Seas is causing massive impacts on the ecology of some ecosystems, and threatening many endangered marine species such as certain sharks, leatherback turtles, albatrosses, etc.

Q: Do you think social marketing, such as the swordfish & caviar campagins run by SeaWeb USA, could help change consumer demand for fisheries such as shark fining. Could this be used to reduce pressure on high seas fisheries? - Nicola Waldron

The swordfish campaign does seem to be a success story. (I don’t think the same can be said for the caviar campaign, because the decline of Beluga sturgeon is not merely an overfishing problem, but also an issue of environmental decline in the Caspian Sea region). But I have limited hope for the potential of consumer awareness campaigns to address this problem, since the bulk of consumers of High Seas-derived products are outside the US.  I happen to think trade sanctions against the worst perpetrators of High Seas destructive fisheries would go farther than consumer campaigns, especially as it is almost impossible to source many marine products coming from offshore areas.