engleski

Loggerhead sea turtles bycatch with bottom trawls in the northeastern Adriatic Sea

Sea turtles interaction with fisheries has always represented one of the most sever threats to sea turtles worldwide, affecting different size classes of animals depending on the fishing method as well as the areas/habitats where the fishing effort is placed. The northern Adriatic Sea hosts one of the most important neritic habitats for loggerhead sea turtles (Caretta caretta) in the Mediterranean and is considered as a bycatch hotspot in terms of trawl and gillnet fisheries, with catch rates ranging in thousands catches per year. In this study, bottom trawl loggerhead bycatch in the northeastern Adriatic Sea, namely in the territorial waters of Croatia and Slovenia, was deeply examined. The mean curved carapace length (CCL) of captured turtles was 54.0 ± 15.4 cm (ranging: 20.0 – 89.0 cm, N = 91), with the majority of animals (64.8%) belonging to larger size classes (> 50 cm CCL). Although bycatch occurred throughout the year, it was positively associated to the “cold season” (November-April, chi-sq. = 11.87, p < 0.01, d.f. = 1), reaching its peak in January-February season. Direct mortality was 7.5% (N = 93), whilst 18 loggerheads (19.4%) were captured in comatose health conditions, suggesting the total (potential) mortality of 26.9%. According to the different methods we have applied, there is evidence that the estimate for total bottom trawl loggerhead bycatch in the study region is of 2135 - 4334 captures per year.

Caretta caretta; mortality; Mediterranean Sea

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