Impact of turbot fishery on cetaceans in the Romanian Black Sea area

Abstract

The abundance of the three species of endemic Black Sea marine mammals represented by Delphinus delphis ponticus (Barabasch-Nikiforov 1935), Tursiops truncatus ponticus (Barabasch-Nikiforov 1940) and Phocoena phocoena relicta (Abel 1905) has shown a dramatic decline due to direct killing practiced in earlier times, incidental catches in fishing gears, depletion of the fish populations entering the cetacean food web, and habitat degradation. These threats are more severe in the Black Sea owing to its semi-enclosed nature, high human density, and human activities being carried out especially in coastal zones. Each year, incidental cetacean catches are registered on the Romanian littoral and, consequently, mortalities occur among individuals which strand on the beaches. These mortalities affect in particular the species Phocoena phocoena, considered the most vulnerable one to gillnet fishing. The greatest hazard for Black Sea marine mammals is turbot gillnets, taking into account their number and distribution area. This paper presents data on the description of the current fishing system used in the commercial fisheries of the Romanian Black Sea area, the geographical distribution of the incidental catches, fishing effort, IUU fishing and ghost fishing, CPUE values of cetacean by-catches, indirect impacts of fisheries and recommendations.