Bycatch of marine mammals in the Northwest Atlantic during commercial fishery (based on literature materials and observations by the Polar branch of VNIRO in 2013-2020)

Abstract

This paper describes one of the most acute problem for both environmental companies and fisheries - bycatch of marine mammals caused by bioresource exploitation in the Northwest Atlantic (NWA). There is no doubt that fishing has some impact on marine mammals, but information on bycatch of marine mammals is needed to understand the extent of the impact of different fishing gears. The paper is based on data from reports of observers of the Polar branch of VNIRO from fishing vessels in the 3LMNO NAFO zone (Newfoundland Island), as well as literary materials. As a result of the analysis, it has been found that small species of marine mammals, such as gray, common, harp seals from the Phocidae family, common dolphin, short-finned pilot whale (Delphinidae family) as well as harbour porpoise from the Phocoenidae family are most often injured by various fishing gears. Toothed whales (sperm whale, bottlenose whale) are the least susceptible to bycatch. Among the baleen whales, humpback whale, northern right whale and minke whale are often the victims of fishing. Gillnets, trawl fishing, and longlines are the greatest threats to small marine mammal species, while baleen whales are most vulnerable to traps, usually to catch ten-legged crustaceans Decapoda. Analysis of the literature has shown that, in general, the stocks of most marine mammal species in the NWA, excluding the northern right whale, are in a stable condition. The manuscript considers measures aimed at reducing bycatch of marine mammals.