Interaction between dolphins and coastal fisheries and using acoustic deterrent in reducing of interaction

Abstract

This study was conducted at the Unye-Ordu coasts of the South-eastern Black Sea, from May 2015 and February 2017, to investigate the frequency of dolphins-bottom gillnet fisheries interactions, the role of using acoustic deterrent in reducing the damage inflicted by the dolphins to the gillnets and to the fish caught in the gillnets. For this purpose, two gillnet sets with similar technical and equipment characteristics were prepared. While one of the groups had acoustic deterrent (active group), the other did not have acoustic deterrent (control group). In the study were used Future Oceans (70 kHz) deterrent. During the study, in only 3 of the 65 fishing trials have determined the interaction of dolphins with gillnets. It was determined that the number of holes in the gillnets caused by the dolphins was 36.3% less in the nets with acoustic deterrent than the control nets. On the other hand, the CPUE value of the whiting was estimated as 2.01 ± 0.23 kg km-1 s-1 in the gillnets with acoustic deterrent and 1.97 ± 0.24 kg km-1 s-1 in the control nets. These results showed that the use of acoustic deterrent does not have a negative effect on the catch of whiting caught in the gillnets.