Preliminary results of cetacean sightings in the eastern Mediterranean Sea of Turkey.

Lack of baseline knowledge is often the principal conservation barrier, especially if the species of concern shows steady decline. The primary goal of the current project is to fill the knowledge gaps in understudied cetacean populations through dedicated visual and acoustic surveys in the Eastern Mediterranean Sea of Turkey. The surveys were conducted over six seasons, following 4384.76 km in 49 days between April 2018 and July 2019. Cetaceans were detected on 39 days (146 sightings), with the highest sightings belonging to delphinids (bottlenose, common and unidentified dolphins) followed by sperm whales (Physeter macrocephalus) and a single acoustic detection of a beaked whale. Fethiye Canyon held the highest cetacean concentration and thus is identified as an "important habitat". Reported encounter rates were higher than previous studies, with 2.78 and 0.55 groups/100 km for delphinids and sperm whales, respectively. Despite the lack of significant variation in cetacean presence due to season and diurnal effects, there was a noticeable increase in summer sightings for sperm whales, where they were encountered as solitary individuals and social units with calves. The current research presented the first seasonal survey results of the Turkish Mediterranean and underlines the importance of local research efforts for valid conclusions in an understudied environment that holds not only unrecognized cetacean habitats but also a wide range of human pressures. [ABSTRACT FROM AUTHOR]