Sedat Gonener, Ugur Ozsandikci
Almost all marine mammal species are in interaction with fishing activities and this interaction frequently re-sults with the death of marine mammals in gillnet fis-heries. This situation which results with the death of thousands of harbor porpoise (Phocoena phocoena) and bottlenose dolphin (Tursiops truncatus) is defined as by-catch ( non-target catch) in gillnet fisheries and in this way it is legalized at least partially. These inre-actions between fisheries and dolphins cause ecologic and social concerns, while that means much more eco-nomic losses from the perspective of fishermen. In most of studies which aim to determine necessary measures to reduce by-catch of dolphins, gillnet fisheries is taken as basis and dolphin deterrent devices called pingers are used. In this subject many studies have been carried out in world, while only a few in Black Sea. However, it is still difficult to make an assessment for effectiveness of pingers. In addition to this, many studies including those of performed in Black Sea outline that pingers can keep harbor porpoise (Phocoena phocoena) and bottle-nose dolphin (Tursiops truncatus) away from gillnets for 1-2 years but it is vital that monitoring the situation after this period.