Monday, August 27, 2012

Shark fins

Over the course of last year a couple of US States and Cities in Canada have decided to ban shark fin products. Canada, which prohibits shark finning, has a heavily regulated shark fishing and trade industry but the import is much less regulated and therefore municipalities such as Toronto, Mississauga, and Nanaimo have started regional efforts to reduce the import. It is a slow process and many communities hesitate as there is opposition to such bans especially from business owners selling shark fin products. A few days ago in an attempt to test what species of sharks are actually sold activists from the Vancouver Animal Defense League tried to obtain shark fin soup samples for DNA testing from a Richmond restaurant owner. Activists and owner got into an argument that went through the press. This again fuels discussions about the pros and cons of such regional bans and their impact on the economy.

Sharks are fascinating but they have been in trouble long before Spielberg's Jaws (which didn't help to make things better). Many humans fear them although there is little evidence indicating that sharks are really very dangerous. Sharks have much more to fear from humans than humans have to fear from sharks.

Most sharks are active predators and eat primarily fish, although the great white shark will also prey upon seals, sea lions and other marine mammals. Some sharks eat bottom-dwelling animals such as crabs, and others scavenge for dead animals. Some sharks such as the whale shark feed rather passively by swimming with their mouth open to collect plankton and small fish. Sharks are high on the ocean's food chain. They typically eat thousands of smaller fish during the course of their lives. As predators, they conserve energy by eating the slow, weak or sick fish in a school. They are, therefore, important to the ecological balance of the marine environment in that they eliminate the genetically weaker animals in a population as well as keeping population sizes in balance. 

From the currently known 30,000 fish species some 1100 are sharks of which 1000 are living in marine waters and 100 occur in freshwater. An alarming 40% of the recorded sharks species at the IUCN are listed as threatened and endangered and for 35% of them sufficient data are missing while only 10 are currently listed on the Convention on International Trade in Endangered Species of Wild  Fauna and Flora (CITES).

Sharks, and their relatives the rays and chimaeras, provide about 1% of world fisheries landings reported to FAO, or some 700,000 to 800,000 tons; perhaps 70-100 million animals. About 60% of these are sharks, around 40% skates and rays. These figures are undoubtedly an underestimate, because many countries under-report their catches and ignore bycatch, discards and recreational fisheries. Actual catches may be twice that reported. Also, there is worldwide concern that the increased demand for shark fins will have a devastating impact on shark populations and stocks. Shark fins are a highly prized commodity in many Asian cultures. Shark fins infer financial status and are traditionally used in soups served at important occasions such as weddings. The increase in middle-class wealth in many shark fin consumer countries has significantly increased the demand for such products; the largest market is Hong Kong. The 2005 FAO estimate of world exports of dried shark fins was US$ 220 million.

 There is strong evidence that populations of sharks and rays have declined considerably in recent times.  This decline is generally attributed to increasing fishing pressure, the effects of which are accentuated by the generally slow growth, late maturity and low reproductive output of most sharks and rays. Other major threats to sharks include habitat alteration, damage and loss from coastal developments, pollution, and the impacts of fisheries on the seabed and food species.

Most shark fisheries around the world are virtually unmonitored and completely unmanaged. However, it is widely recognized that the need for introducing shark fisheries management is now very urgent and that a precautionary approach to the management is essential. One of the major problems associated with monitoring and enforcement is the likelihood of misidentification. This can arise both because some shark and ray species are difficult to distinguish morphologically, and because of ethnic differences in understanding or interpreting common names. Also, little is known of the identity of species in confiscated shark fin catches and processed shark meat, but in recent years genetic approaches have been deployed to resolve this issues. Way back in 2002 Mahmood Shivji and colleagues proposed a multiplex primer method to identify a few shark species from body parts and in 2009 we published a study about  the successful DNA Barcoding of shark fins confiscated in Australia. Over the years researchers have assembled DNA reference Barcodes for 51% of all elasmobranch species (

Unfortunately this work largely went unnoticed and several attempts to obtain funds for a global collaborative project to assemble a barcode library for the remaining species were unsuccessful. The figure above and some text in this blog are part of some of my own unsuccessful grant proposals. They either didn't fit the portfolio of some funding agencies at that time or simply weren't attractive enough. This might have changed though. A collaborative study of the Stony Brook University in New York, the Field Museum in Chicago and Pew Environment Group in Washington, D.C. barcoded samples of shark fin soup in 14 U.S. cities and their results went through the press also triggering the events described at the beginning. They were able to detect the presence of shark in just 32 of 51 bowls of soup. Of those, six could not be linked to a particular species, but the rest were identified. Those identified were all threatened (one endangered) or vulnerable, according to the IUCN Red List. 

The real issue is not the cruel practice of shark finning as such. No doubt it is bad and absolutely unnecessary. However, a ban of shark fins can only be the beginning. Sharks and rays need far more protection from humans as they are also fished for other food items, cosmetics, and pharmaceuticals, the latter leading to products of highly questionable benefit. It is a multimillion dollar business to the expense of these mighty ocean creatures.

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