Updated Estimates of Mortality and Injury of Cetaceans in the Hawaii-Based Longline Fishery, 1994-2005; Technical memo

摘要

This report presents updated estimates of annual mortality and serious injury of cetaceans for the Hawaii-based longline fishery during 1994-2005, including information on set type and targeted fish species. The fishery has targeted primarily tunas and swordfish, although swordfish sets were prohibited north of the equator by Hawaii-based vessels between 2001 and early 2004. Observer coverage ranged from 3.6% to 5.5% during 1994-1999 and then increased to 22-34% during 2001-2005. Estimated fishing effort totaled 159,572 sets, including 122,864 sets targeting tunas, 13,160 sets targeting swordfish, and 23,548 sets targeting species other than swordfish using swordfish-style methods. Annual effort was roughly constant at about 12,000 sets through 2001 and then increased to over 18,000 sets through 2005. During 24,542 observed sets, 67 cetaceans were observed hooked or entangled. Seven of the observed cetaceans were dead (2 short-finned pilot whales, Globicephala macrorhynchus, 2 false killer whales, Pseudorca crassidens, 1 pan-tropical spotted dolphin, Stenella attenuata, 1 bottlenose dolphin, Tursiops truncatus, and 1 Blainvilles beaked whale, Mesoplodon densirostris). The 60 other hookings and entanglements involved injuries of 18 false killer whales, 9 Rissos dolphin, Grampus griseus, 5 short-finned pilot whales, 3 bottlenose dolphins, 2 spinner dolphins, Stenella longirostris, 3 humpback whales, Megaptera novaeangliae, 1 sperm whale, Physeter macrocephalus, 1 short-beaked common dolphin, Delphinus delphis, 1 Bryde's whale, Balaenoptera edeni, 1 Blainville's beaked whale, and 16 unidentified cetaceans.