Fishing activity and impacts along the main nesting area of loggerhead sea turtle Caretta caretta in Italy: overwhelming discrepancy with the official data

Abstract

The southern coast of Ionian Calabria was recently recognized as the main nesting area of the loggerhead sea turtle Caretta caretta in Italy. The aim of this study was to characterize the fishing fleet in this area in terms of number of boats, economic situation, social aspects and impact on sea turtle specimens and target species. A multidisciplinary approach was essential to understand how the conservation problems of C. caretta are linked to various characteristics of the fishing fleet. Our data showed a vast discrepancy between the official census and the actual number of boats fishing in the area: 87% of the observed artisanal vessels lacked a required registration number, and thus were fishing illegally. This has caused serious social problems that worsened over the summer of 2007, when the presence of non-local registered vessels, using drift nets, generated a spatial conflict with the local artisanal fishermen. We identified 11 fishing gears used in the area and four of them were studied with on board observations: illegal drift nets, trammel nets, bottom longlines and longlines targeting swordfish. The total number of turtles caught during the summer in the area by longliners targeting swordfish was calculated to be 500 (±180 SE). In addition the presence of drift netters had a negative impact from an ecological and social point of view.