Whale Cetaceans

• Bycatch
Several species of small whales are caught as bycatch in fisheries for other species. In the Eastern Tropical Pacific tuna fishery, thousands of dolphins drowned in purse-seine nets, until preventive measures were introduced. Gear and deployment modifications, and eco-labelling (dolphin-safe or dolphin-friendly brands of tuna), have contributed to a reduction in dolphin mortality by tuna vessels.
• Naval sonar
Environmentalists speculate that advanced naval sonar endangers some cetaceans, including whales. In 2003 British and Spanish scientists suggested in Nature that the effects of sonar trigger whale beachings and to signs that such whales have experienced decompression sickness. Responses in Nature the following year discounted the explanation.