A global review of porpoise (Cetacea: Phocoenidae) mortality in gillnets

Can local ecological knowledge be used to assess status and extinction drivers in a threatened freshwater cetacean?

“…Fisheries by-catch has been identified as the principal cause of mortality in many populations of porpoises and other small cetaceans worldwide (Jefferson and Curry, 1994;Reeves et al, 1997Reeves et al, , 2003Jaramillo-Legorreta et al, 2007), and it may also constitute a serious problem for long-term survival of the Yangtze finless porpoise population. Although our analysis does not suggest an increase in by-catch mortality rates over time, management interventions to reduce levels of incidental by-catch both from nets and long-lines and from electro-fishing should remain a priority for finless porpoise conservation, especially in regions of high porpoise abundance.…”

Baseline study of perfluorochemicals in harbour porpoises (Phocoena phocoena) from Northern Europe

“…The harbour porpoise has almost disappeared from the Baltic Sea and the winter migration between the Baltic and North Sea has decreased (Jefferson and Curry, 1994;Koschinski, 2002). The harbour porpoise population in the North Atlantic has been targeted both by direct hunting and as by-catch in commercial fisheries throughout their range (Jefferson and Curry, 1994). Declines in porpoise populations may also be directly related to habitat loss (e.g.…”

Dolphins, whales and porpoises : 2002-2010 conservation action plan for the world's cetaceans

“…Many additional cases have been identified since then (Perrin et al 1994;Jefferson and Curry 1994;Northridge and Hofman 1999), including: the Taiwanese driftnet fishery for sharks, tunas, and mackerel (family Scombridae) off northern Australia (Harwood and Hembree 1987); the Italian and Spanish driftnet fisheries for swordfish in the Mediterranean Sea (Notarbartolo di Sciara 1990; Silvani et al 1999); the French tuna driftnet fishery in the north-eastern Atlantic (Goujon et al 1993); and coastal gillnet fisheries in the United States (Bisack 1997), Canada (Trippel et al 1996), western Europe (Tregenza et al 1997;Vinther 1999), the Black Sea (Pavlov et al 1996), and Brazil Pinedo and Polacheck 1999). Gillnet mortality is viewed as the chief threat to the survival of the Critically Endangered vaquita Rojas-Bracho and Taylor 1999) ( Figure 3) and the Endangered Hector's dolphin (Martien et al 1999;Dawson et al 2001).…”

“…Finless porpoises, like other phocoenids (Jefferson and Curry 1994), are extremely susceptible to entanglement in gillnets, and large numbers have been, and continue to be, killed throughout their range (Jefferson et al 2002b). Despite the fact that it is illegal, electric fishing has become widespread in the Yangtze system during the last decade, and it probably kills porpoises outright and contributes to the depletion of their prey .…”