Loggerhead Turtle (Caretta caretta) bycatch, case study: Mediterranean Sea

Some studies were performed to evaluate the effect on sea turtle bycatch with the setting depth of longlines. Increasing the set depth for longlines has been found to reduce the overall catch rates of turtles. In the Ionian Sea preliminary results (project Life Nature 2003 - NAT/IT/000163) seemed to indicate that most sea-turtle bycatches happened when hooks were set at between 10 and 15 m deep, however, more data is needed to confirm whether this is a significant result. Other studies (Laurent et al., 2001) showed that the maximum depth at which the marine turtles were caught was 60 m for swordfish longline and 20 m for albacore longline. There are concerns though that the deeper setting of longlines may result in an increase in mortality rate of turtles that are hooked and die through drowning.