Original scientific paper
Seasonal encounter rates and residency patterns of an unstudied population of bottlenose dolphin (Tursiops truncatus) in the northwestern Levantine Sea, Turkey
Aylin Akkaya Baş
orcid.org/0000-0002-0414-770X
; Marine Mammals Research Association, Antalya, 07070, Turkey
Mehmet Akif Erdoğan
; Marine Mammals Research Association, Antalya, 07070, Turkey
Neil Richard Charles Morris
; Marine Mammals Research Association, Antalya, 07070, Turkey
Kathryn Yeoman
; Marine Mammals Research Association, Antalya, 07070, Turkey
Ophélie Humphrey
; Marine Mammals Research Association, Antalya, 07070, Turkey
Elisa Gaggioli
; Marine Mammals Research Association, Antalya, 07070, Turkey
Chloe Roland
; Marine Mammals Research Association, Antalya, 07070, Turkey
Abstract
Insufficient data regarding abundance, distribution and movement patterns of bottlenose dolphins has contributed to lack of effective conservation strategies within the Levantine Sea. It has been inferred that the bottlenose dolphin population has decreased by 30 % in the last 60 years, thus a basin wide research effort on the population is an urgent priority. We present the preliminary results of the first bottlenose dolphin photo-identification study in the northwestern Levantine Sea. 32 boat surveys were conducted from March 2015 to July 2016, totalling 1433 km of survey effort. Current study reported an uneven distribution, high seasonal encounters and varied residency patterns of bottlenose dolphins within the northwestern Levantine Sea. We propose that the northwestern Levantine Sea, specifically the coastal waters of Antalya Bay, indeed is an important bottlenose dolphin habitat and adjacent waters may be of similar significance. Of the 56 individuals catalogued, 13 were re-sighted in both years. Encounter rates varied seasonally, with a peak in spring of 12 groups and 100 individuals per 100 km. Dolphin presence was not detected during autumn and winter. While seasonal, visitor and transient dolphins were reported, no year-round residency was documented. Incidental observations of visible starvation signs and skin parasites suggested individual dolphins in this region could be under anthropogenic stressors. The results reported here highlight the importance of baseline information on encounter rate, distribution and residency pattern as they have a key role on the assessment of population statues and the threats they are facing. Future studies with annual survey effort, have to be continued in the northwestern Levantine Sea and its adjacent waters.
Keywords
bottlenose dolphins; encounter rates; residency patterns; seasonality; photo-identification; conservation strategies; important habitat; Levantine Sea
Hrčak ID:
176791
URI
Publication date:
1.1.2017.
Visits: 1.994 *