Overfishing and Finning are Leading Causes in Shark Extinction

26 Jun

People do not care about wildlife until wildlife affects their bottom line. Sadly this time the response from the scallop farmers does not appear to be great enough to save several shark species from extinction. The Guardian and The New York Times have both published articles explaining how the loss of sharks from the natural environment has harmed scallop farmers. Basically, sharks eat various species of rays and the rays eat the scallops. The sharks survive by preying on rays. As a result there are fewer rays to eat the scallops. However, because of overfishing and finning (hunting sharks for their fins) the number of sharks in the oceans have decreased. With fewer predators the ray populations have exploded. Since there are more rays they require more scallops to sustain themselves. As a result there are fewer scallops for fishermen to fish. (From ScienceDaily)

In 2008 nine new species of sharks were added to the World Conservation Union (IUCN) red list, of endangered species. This week Grist reported that one third of all open ocean sharks face extinction. There are several hundred different species of sharks. They make up eight different orders and have been around since the Jurassic period. Large sharks have no natural predators. Many of the smaller sharks have natural predators. They are preyed upon by the larger shark species. However, no cross section of sharks has been spared from the risk of extinction. Even well known sharks like great white sharks and hammerhead sharks are endangered.

The real problem, which is a common one when talking about ecosystems, is that we do not know what impact the loss of these shark populations will have on the rest of the ecosystem. Off the coast of North Carolina we have seen a loss in the number of scallops and clams because the scalloped hammerhead sharks numbers have decreased by almost 99% in the last 30 years, which has resulted in an explosion of the cownose ray population. The cownose ray is just one of 12 species in the scalloped hammerhead shark’s diet. We have no idea what other changes this ecosystem is seeing.

We have seen a snapshot of the problem and some of the ripple affects of the reduced number of sharks in the ocean. This problem has potential to be much worse than we currently know and we are limited in our approaches to placing the ecosystem back in balance. However, we do know how it got out of wack. Shark meat is delicacy in many parts of the world. Additionally, their fins are believed to have healing properties. In recent years the demand for shark meat and fins has soared.  Therefore, fishermen are trying to catch more sharks. Additionally, “(t)here are currently no restrictions on the number of sharks that these fisheries can harvest,” Fordham told AFP by phone. “Despite mounting threats, sharks remain virtually unprotected on the high seas.” The final factor to work against sharks is that since they are predators they take many years to reach sexual maturity and they have very few young during each breeding cycle, so their numbers take a long time to recover from overfishing.

Atlantic porbeagle failed to earn protection at the last meeting of the Convention on International Trade in Endangered Species (CITES), in 2007. Canada led the charge to block the protective measure, supported by Argentina, New Zealand and some Asian countries. Porbeagle meat is very variable in Europe.

Finning is illegal in international waters, but is highly unregulated.

It’s sad to say but being placed on the IUCN red list will hopefully help save these sharks species. If they are protected by CITES it will no longer be legal to trade or sell the animals. Sharks have played an important role in marine ecosystems for more than 400 million years. Not having them will surely have devasting consequences.

Shark Alliance is a not-for-profit coalition of NGOs dedicated to restoring and conserving shark populations by improving European fishing policy.

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Posted by on June 26, 2009 in sustainability, wildlife


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