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Sea Turtle Highly Migratory Species Laysan Albatross Dolphin jumping out of the water. Whale
(Above image courtesy, illustration left courtesy

As referenced in the Ecosystem Overfishing illustration on our Overfishing page, hundreds of thousands of whales, dolphins, turtles, sharks and other species are dying from entanglement in fishing gear such as nets. This destruction of marine animals is known as bycatch. One of the papers submitted to the International Whaling Commission (IWC) 55th Annual meeting estimated the loss specifically within the cetacean family (whales, dolphins and porpoises) to be between 200,000 to 400,000 drown each and every year or about 850 per day as a result of bycatch killing. (Read, A. J., Drinker, P., and Northridge, S., 2003, p.4)  The paper's lead author, Andy Read of the Duke University Marine Laboratory is also co-chair of World Wildlife Fund's Cetacean By-catch Task Force. Read was quoted as saying "This level of bycatch is no doubt significantly depleting and disrupting many populations of whales, dolphins and porpoises. If nothing is done, several species will be lost in the next few decades." This is now the leading threat to the survival of the world's 80-plus species of whales, dolphins and porpoises, according to the paper's co-author  Simon Northridge.  

Some species are already on the brink of extinction as a result of bycatch.  For example, in Mexico's Gulf of California, up to 15% of the critically endangered Vaquita porpoise population is killed every year in fishing nets. The current population, found nowhere else on earth, is estimated at fewer than 600. (World Wildlife Federation, 2004, p. 5)  Bycatch may also be jeopardizing the continued existence of the loggerhead and leatherback sea turtles off the eastern U.S. seaboard in the Atlantic. (NMFS, National Oceanic and Atmospheric Administration, 2002, sec. 1.1)

However, the problem is not limited to the drowning of the air-breathing cetacean family. Some fishing techniques result in billions of pounds of fish and other marine life being discarded each year. Unwanted creatures are returned dead to the sea because they are undersized or unwanted. Worldwide, it is estimated that fishermen discarded about 25% of the total catch during the 1980's and in the early 1990's. This adds up to about 60 billion pounds each year!! (Alverson, D.L., M.H. Freeberg, S.A. Murawski, and J.G. Pope. 1994. Alverson 1998)

This is an urgent and difficult problem as the demand for fish continues to grow.  Solutions must be found to control commercially fishing in a manner which does not result in this large-scale bycatch. "Solutions to cetacean bycatch are out there," said Karen Baragona, deputy director of WWF's Species Conservation program. (World Wildlife Federation, 2003) She continues "but to tackle the problem on a global scale, we need to boost political will, increase funding for research on cetacean-friendly ways of fishing, and tap into the creativity of fishermen--so that whales and dolphins are protected and fishermen can keep earning a living." Solutions to the problem of entanglement vary by region and species involved. They can include adding gillnet floats that break away when hit by a whale or by use of acoustic "pingers" that warn marine mammals away from nets and buoy lines so that these are less likely to snare whales and dolphins. Scientists acknowledge that fishermen have been crucial in developing these successful gear modifications. (World Wildlife Federation, 2003)


What can you do about it?


  • Buy your seafood from fisheries using non-destructive fishing techniques. A wallet-sized, easy to use list of fish that are caught in a sustainable fashion and are not toxic or hazardous to your health, can be downloaded from the Monterey Bay Aquarium's Seafood Watch. Another good source of information is the Seafood Choices Alliance.
  • Your Voice counts. Use our letter writing area to make sure your opinions and concerns are heard by government and industry leaders. Let them know that you support the creation of Marine Reserves.
Continue to learn of other threats to our marine environment.  Read our HABITAT ALTERATION page.

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