PIFSC Sea Turtle Longline Research EA June 1, 2009
dolphin have been observed in the vicinity of longline gear. Sperm whales have also been observed taking fish from gear (Gilman et al. 2006).
The Hawaii deep-set commercial longline fishery is identified by NMFS as a Category I fishery per the MMPA and the shallow-set fishery is identified as a Category II fishery because these fisheries have frequent incidental mortality and serious injury of marine mammals (FR 73(231):73056, 12/01/08), including bottlenose dolphins, false killer whales, humpback whales, Risso’s dolphins, short-finned pilot whales, spinner dolphins, pantropical spinner dolphins, and sperm whales. The Biological Opinion for proposed Amendment 18 determined that the endangered humpback whale would be likely to be adversely affected, but not the endangered blue whale (Balaenoptera musculus), the endangered fin whale (B. physalus), the endangered sei whale (B. borealis), the endangered sperm whale (Physeter macrocephalus), nor the endangered North Pacific right whale (Eubalaena japonica) (NMFS 2008a).
No takes of baleen whales, including sei, blue, humpback and fin whales, have been observed (12 years of observation data) in the Atlantic highly migratory species fishery (SWFSC 2007).
Intentional injury or mortality of depredating cetaceans may have important population-level effects in terms of numbers and/or distribution, especially for small isolated populations associated with oceanic islands. For example, there is concern over the ecological effects of longline interactions with genetically-distinct population of false killer whales around the Hawaiian Islands nearshore (insular) stock, Hawaiian Islands pelagic stock, and Palmyra Atoll stock, which are also genetically distinct from stocks elsewhere in the eastern Pacific Ocean. All three stocks associated with the Hawaiian Islands and Palmyra Atoll interact with foreign and domestic pelagic longline fisheries. The total annual estimated mortality and serious injury of the Hawaiian stock of the false killer whale exceeded the level allowable under the Marine Mammal Protection Act (MMPA), and this stock has been considered “strategic” under the MMPA since 2000 (Forney and Kobayashi 2007). Questions, however, have been raised regarding the assumption that insular stocks do not interact with pelagic longline fisheries and therefore whether this stock should be declassified from strategic (R, Baird, Cascadia Research Collective comments (10/08) on Pseudorca draft Stock Assessment Report, NMFS (05/08)).
Fishing experiments to test the effectiveness of sea turtle bycatch strategies conducted on domestic and foreign fishing fleet vessels would attempt to avoid areas with either reports of high cetacean presence or when the vessel has already caught a cetacean on gear, which increases the risk of catching additional cetaceans, as cetaceans often occur in groups. Known areas with cetaceans that have habituated to seeking out fishing vessels as a source of food would also be avoided. All vessels involved in field studies would have equipment for safely dehooking and disentangling any cetaceans caught in gear, with researchers experienced in its effective use. No field studies would be conducted in the Hawaiian Islands Humpback Whale Marine Sanctuary during the winter season when humpbacks are present.
Studies conducted in commercial fisheries would be expected to have cetacean bycatch no higher than that experienced by the commercial fisheries under typical conditions due to the PIFSC field studies conducted during normal fishing operations than what would occur on the domestic and foreign fishing vessels without the field study. It is highly possible the mortality would be