Proceedings of the 27th Annual ISTS: Mapping fisheries and their potential threat to sea turtles in the eastern Pacific Ocean

Shaleyla Kelez, Emily Bryant, Jennifer Laliberte, Daniel Dunn, Wallace J. Nichols and Larry B. Crowder. 2008. Mapping fisheries and their potential threat to sea turtles in the eastern Pacific Ocean. In: Rees, A.F., M. Frick, A. Panagopoulou and K. Williams., compilers. Proceedings of the Twenty-Seventh Annual Symposium on Sea Turtle Biology and Conservation. NOAA Technical Memorandum NMFS-SEFSC-569, 262 p.

Several sea turtle populations in the Central and South East Pacific Ocean (from Mexico to Chile) are currently experiencing critically low numbers. Species affected include; i. The hawksbill sea turtle (Eretmochelys imbricata) – whose numbers have been so low that it is considered rare since the 1980s, ii. The leatherback sea turtle (Dermochelys coriacea) – nesting numbers at several beaches have declined drastically in the last 20 years with some populations that numbered in the thousands now approaching regional extirpation, iii. The loggerhead sea turtle (Caretta caretta) – Both nesting populations in the Pacific (in Japan and Australia) have experienced severe population declines in the last 25 years. Individuals from 176 both of these nesting populations inhabit the Eastern Pacific Ocean during the pelagic juvenile stage of their life cycle. There is also concern regarding the population size of green turtles (Chelonia mydas) and olive ridley turtles (Lepidochelys olivacea) in the Pacific, although these populations do not seem to be as severely under threat as the three listed above. Fisheries represent a significant threat to these populations and it is extremely important to identify the level of threat imposed by each specific fishing industry and to determine ways to minimize the impact of by-catch across all fishing gears. As one step towards this objective, Project GLOBAL has been gathering information about fisheries, fishing effort and by-catch in the Eastern Pacific. The project is not limited to investigating only sea turtle by-catch, but also looks at marine mammals and sea birds. We are concentrating our efforts on the effect of three major gear types (longlines, trawls and gillnets) on these taxa. Here we present a synthesis of that information as it pertains to sea turtles to address the potential threat that each fishery represents in space and time for each population, taking into account the relative threat to different life stages. We hope to be able to identify critical areas in time and space where interactions between sea turtles and fisheries are most likely to impact population levels. This information will help facilitate the successful prioritization and implementation of mitigation measures by fisheries managers.