Mortality of dolphins and porpoises in coastal fisheries off Peru and southern Ecuador in 1994

Of 722 cetaceans captured mostly in multi-filament gillnets and landed at Cerro Azul, central Peru, in 87 days during January-August 1994, 82.7% were dusky dolphin Lagenorhynchus obscurus, 12.6% Burmeister's porpoise Phocoena spinipinnis, 2.4% long-beaked common dolphin Delphinus capensis and 2.4% bottlenose dolphin Tursiops truncatus. The total kill estimate for a seven-month period, stratified by month, was 1567 ± 237 (SE) cetaceans. Data collected at 16 other ports showed that high levels of dolphin and porpoise mortality persisted in coastal Peru at least until August 1994 when an unimplemented 1990 ban on small cetacean exploitation was renewed. Circumstantial evidence suggests that, thereafter, increasing enforcement reduced direct takes and illegal trade in meat but also hampered monitoring. The absence of abundance data precludes any assessment of impact on populations. An interview study in October-December 1994 of the extensive multi-filament gillnet fishery from Puerto Bolivar in southern Ecuador indicated, despite a low catch rate per boat, an estimated annual take of 227 bottlenose dolphins in the inner estuary of the Gulf of Gaayaquil. This represents some 9% of the resident bottlenose dolphin population, or more than twice its estimated birth rate. Two mono-filament gillnet boats did not report any entangled cetaceans.