Behavioral responses of sea turtles to lightsticks used in longline fisheries

Sea turtles are sometimes inadvertently captured by pelagic longline fisheries. As a consequence, some drown or suffer injuries, and longline bycatch has been identified as one factor contributing to the decline of marine turtle populations. Understanding what stimuli attract turtles to longlines will therefore be useful in efforts to reduce the number of turtles that become hooked or entangled. Lightsticks, which are often placed on longlines to attract tuna (Thunnus sp.) and swordfish Xiphus gladius, may also attract sea turtles. To investigate this possibility, we conducted laboratory experiments with captive-reared juvenile loggerheads Caretta caretta and wild-caught post-hatchling loggerheads to study their responses to these lights. Both age classes oriented toward glowing lightsticks, suggesting that such lights may play a role in attracting turtles into the vicinity of longlines.