Quantifying Sea Turtle Mortality with PSATs

Quantifying Sea Turtle Mortality with PSATs 1 New Discoveries in the Olfactory Capability of Sea Turtles 6 MHLC7—Evaluation and Comment 10 Compendium—Fisheries Research in Brief 11 (continued on page 2) The incidental capture of marine turtles in longline fishing gear is generally accepted to be a significant factor contributing to the decline of sea turtle populations in both the Pacific and Atlantic Oceans (Heppell et al., 1999; NMFS, 2001a). Pelagicstage juvenile hard-shelled turtles (e.g., Loggerheads, Caretta caretta) are generally hooked in the mouth, presumably because they have bitten baited hooks (Figures 1 and 2), whereas Leatherback turtles (Dermochelys coriacea) are most often hooked in the flippers or entangled in fishing lines. While most turtles that interact with longline gear are eventually released alive, they are often released with hooks remaining in their mouths, throats, gastrointestinal tracts or flippers (Aguilar et al., 1995; Oravetz, 1999). The ultimate effects of these hooks and the stress of capture are unknown. Rates of postrelease mortality have not yet been adequately quantified, and available estimates are highly controversial. Given the growth in U.S.-permitted longline fishing vessels in both the Pacific and Atlantic over the past two decades (Hoey, 1996; Ito and Coan, 1999), the question of post-release mortality rates holds growing importance. Figure 1. A subadult Olive Ridley Sea Turtle (Lepidochelys olivacea) hooked in longline fishing gear (photo by Yonat Swimmer).