Fishing Casualties

Fishing has dwindled the numbers of the pantropical spotted dolphin, a Pacific Ocean inhabitant, at a worrying rate. Initially the cause was traced to 'bycatch' cases in which animals are unintentionally caught in fishing nets with the targeted species. However, studies done by Katie Cramer of Scripps Institute of Oceanography and researchers from the National Oceanic and Atmospheric Administration showed fishing disrupted the reproductive output of the dolphins. It separated suckling calves from mothers and interfered with conception. Fishing activities were launched in the eastern tropical Pacific in the 1950s for the yellowfin tuna fish that swim with dolphin schools. This led to massive mortalities of the pantropical spotted dolphin. With new fishing techniques put in place, bycatch deaths declined by the 1990s but dolphin numbers did not increase. The study proved this to be due to effects of fishing that went beyond direct bycatch kill.


Down To Earth, January 2009