for National Geographic News
Fishing nets intended for other marine species are killing at-risk species of dolphins and porpoises around the world, according to a report commissioned by the nonprofit World Wildlife Fund-U.S.
Leading marine scientists ranked dolphins and porpoises across the globe for the risk they face from lethal fishing nets. Ten species are included in a list of populations conservationists say require urgent action to prevent further deaths. The report lists the following priority locations and species:
Philippines and Southeast Asia: Irrawaddy dolphins
Zanzibar (East Africa): Indo-Pacific humpback dolphins and Indo-Pacific bottlenose dolphins
Black Sea: Harbor porpoises
Philippines: Spinner dolphins and Fraser's dolphins
Ghana and Togo (West Africa): Atlantic humpback dolphins
Peru: Burmeister's porpoises
Argentina, Uruguay, and Brazil: Franciscana dolphins
Argentina: Commerson's dolphins
Researchers say most of these species are killed by gillnets. Made of monofilament (single-strand) nylon mesh, gillnets are difficult for dolphins and porpoises to see or detect with their sonar.
Once entangled in netting or its supporting ropes, marine mammals face high risk of drowning. Driftnets and crab nets can also kill the mammals. Nontarget species accidentally caught in fishing equipment are known as bycatch.
"Almost one thousand whales, dolphins, and porpoises die every day in nets and fishing gear," said Karen Baragona, of the WWF species-conservation program.
The new report will be submitted to the International Whaling Commission (IWC) at its annual meeting next week in South Korea.
Last year the U.S. Commission on Ocean Policy identified bycatch as the greatest global threat to cetaceans (whales, dolphins, and porpoises). Marine experts estimate that more than 300,000 cetaceans are killed by fishing gear every year.
Randall Reeves, lead author of the WWF-U.S. report, chairs the World Conservation Union's Cetacean Specialist Group, based in Gland, Switzerland. He says the study team focused on identifying cetacean species or populations most likely to end up as bycatchespecially those where the prospect of successful mitigation measures appeared good.
"It's crucial to give guidance to agencies and organizations on how they should invest their resources," Reeves said.
Baragona, of the WWF-U.S., says accidental dolphin and porpoise deaths can be significantly reduced, often with simple, low-cost solutions.
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