Reducing sea turtle bycatch with net illumination in an Indonesian small-scale coastal gillnet fishery

Abstract

Small-scale fisheries are economically and culturally important throughout the world’s coastal waters. These fisheries, however, often have high bycatch rates of protected marine species. Bycatch in small scale gillnet fisheries is thought to be a major driver behind the declines of several sea turtle populations. Recent studies addressing this issue have identified net illumination as a potentially effective bycatch reduction technology (BRT) to reduce sea turtle interactions with gillnet fisheries. In Southeast Asia, small-scale gillnet fisheries make up a large components of fishing effort often in areas that overlap with important sea turtle habitat. We conducted controlled experiments of net illumination as a potential BRT to reduce sea turtle bycatch in a coastal gillnet fishery based in Paloh, West Kalimantan, Indonesia. Results indicated that net illumination significantly reduced multi-species sea turtle bycatch by 61.4% and specifically green sea turtles (Chelonia mydas) by 59.5%, while the CPUE of total catch and target species remained similar. Moreover, this study suggests that Indonesian fishers can increase their overall market value when using net illumination as the market value per unit effort (MVPUE) of both the total catch and target catch showed significant increases. These results suggest that net illumination could be an effective sea turtle conservation tool for small-scale coastal gillnet fisheries in Indonesia and potentially throughout Southeast Asia. In addition, data from the control treatments of this study also provided the first observer based sea turtle bycatch estimate for a small-scale gillnet fishery in Southeast Asia. Challenges to the broad scale implementation of net illumination to reduce this bycatch of sea turtles include the cost, availability of the technology, socialization of the BRT to fishers, and government interest and support for net illumination as a tool for bycatch reduction.