Southern Black Sea

Cetacean abundance; Acoustic backscatter in the water column; Cetacean behaviour

Observers; Fish-finder echosounders

Large numbers of small cetaceans had been hunted in the Black Sea until hunting cetaceans was banned in Turkey starting in 1983. Even though hunting cetaceans had been ceased by Turkish fleets, cetacean populations had not recovered fully due to many other stressors present in their habitat. There are still ongoing threats such as seismic surveys conducted for petroleum, natural gas and hydrocarbon exploration, overfishing and pressure from fishermen for the repeal of the hunting ban. One of the most striking reasons why any action cannot be taken to overcome these stressors and threats is the insufficient knowledge about the importance of the issue. This study aims to play significant role in conservation of these species evaluating the abundance and distribution data it provides about Black Sea cetaceans. To fulfill this role, during the monthly cruises held in July and October 2014, active and passive acoustics methods were performed over transects covering up to 120 miles off the Black Sea coast of Turkey. For the active acoustics, tree transducers (38kHz, 120kHz and 200kHz, SIMRAD EK60, Scientific echo sounder, SIMRAD EK System) were operated continuously over the cruise transects. For the passive acoustics, C-POD (Chelonia Ltd., Cetacean Monitoring Systems) was deployed on the 93 stations. Dolphin presence in echograms were validated with cetacean observation data. Then, normalization and generalization of dolphin sounds was performed using the Echoview software (Echoview Sound Knowledge, copyright 1997-2014 Myriax Software Pty Ltd). C-POD data was used both for validation of cetacean species and characterization of cetacean vocalizations. Parameters: Observation (mainly on group size, species and behavior), Fisheries acoustics (echograms), C-POD acoustics (sound characteristics of click trains like SPL, frequency, bandwidth..etc) Instruments: Nikon ACULON A211 10-22x50 binoculars, three scientific echo-sounders (38kHz, 120kHz and 200kHz, SIMRAD EK60, Scientific echo sounder, SIMRAD EK System), CPOD (Chelonia Ltd., Cetacean Monitoring Systems)

Institute of Marine Sciences, Middle East Technical University
P.O.Box 28
Erdemli
Mersin
33731
Turkey