- Yayın: The effects of marine traffic on the behaviour of Black Sea harbour porpoises (Phocoena phocoena relicta) within the Istanbul Strait, Turkey
- Yazarlar: Aylin Akkaya Bas1,2,3*, Fredrik Christiansen4, Ayaka AmahaOzturk1,2, Bayram Ozturk1,2, Caley McIntosh3.1 Faculty of Fisheries, Istanbul University, Beyazit, Istanbul, Turkey, 2 Turkish Marine Research Foundation, Beykoz, Istanbul, Turkey, 3 Marine Mammals Research Association, Antalya, Turkey, 4 Cetacean Research Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150 Australia
- Dergi: Plos One
Abstract: Marine traffic is threatening cetaceans on a local and global scale. The Istanbul Strait is one of the busiest waterways, with up to 2,500 vessels present daily. This is the first study to assess the magnitude of short- and long-term behavioural changes of the endangered Black Sea harbour porpoises (Phocoena phocoena relicta) in the presence of marine vessels within the Istanbul Strait. Markov chains were used to investigate the effect of vessel presence on the transition probability between behavioural states (diving, surface-feeding and travelling), and to quantify the effect on the behavioural budget and bout length (duration of time spent in a given state) of porpoises. Further, the changes on swimming directions of porpoises in relation to vessel speed and distance was investigated using generalized linear models. In vessel presence, porpoises were less likely to remain in a given behavioural state and instead more likely to switch to another state. Because of this, the bout length of all three behavioural states decreased significantly in the presence of vessels. The vessel effect was sufficiently large to alter the behavioural budget, with surface-feeding decreasing significantly in the presence of vessels. However, when taking into account the proportion of time that porpoises were exposed to vessels (i.e. 50%), the measured effect size was not large enough to significantly alter the animals’ cumulative (diurnal) behavioural budget. Additionally, vessel speed and distance had a significant effect on the probability of porpoises showing a response in their swimming directions. The southern and middle sections of the Istanbul Strait, which have the heaviest marine traffic pressure, had the lowest porpoise sightings throughout the year. Conversely, northern sections that were exposed to a lesser degree of marine traffic hold the highest porpoise sightings. The effect shown in this study in combination with increasing human impacts within the northern sections should be considered carefully and species-specific conservation actions, including establishment of protected areas, should be put in place to prevent the long-term consequences of marine traffic on the Black Sea harbour porpoise population.
- Yayın: Seasonal encounter rates and residency patterns of an unstudied population of bottlenose dolphin (Tursiops truncatus) in the northwestern Levantine Sea, Turkey
- Yazarlar: Aylin Akkaya Bas*, Mehmet Akif Erdoğan**, Neil Richard Charles Morris*, Kathryn Yeoman*, Ophelie Humphrey*, Elisa Gaggioli*, Chloe Roland*
Marine Mammals Research Association, Antalya, Turkey*, Geographical Information System Division, Department of Architecture and Urban Planning, Cukurova University**
- Dergi: Hyla
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, totaling 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.
Yayın: Recent sightings of the Mediterranean monk seal Monachus monachus and evaluation of anthropogenic activities with recommended conservation implications in Antalya Bay, Turkey.
Yazarlar: Aylin Akkaya Bas*, Nicola Piludu, João Lagoa and Elizabeth Atchoi,
Marine Mammals Research Association, Antalya, Turkey**
Dergi: The Monachus Guardian
Abstract: The Mediterranean monk seal Monachus monachus has been classified as critically endangered for over 50 years, and after a difficult recovery, the species has recently been downgraded to endangered. Although the Turkish coast remains one of the few refuges for the species and there are laws for its protection, anthropogenic impacts due to tourism and development still represent the greatest threat to its survival. We report the most recent sightings of Mediterranean monk seals from the Turkish Levantine Sea, investigate boat-seal interactions in the area, and propose number of conservation measures. Seals, including two mother/pup pairs, were sighted on 13 different days during the spring and summer months of 2015 and 2016. Our study suggests that Antalya holds an important seal population, as well as possibly one or more breeding caves. The same area is characterised by intense boat traffic, fishing and recreational activities. Our findings indicate that speedboats and tourism activities are important causes of disturbance, and conversely that seals in Antalya Bay show some degree of habituation to the presence of fishing boats. Conservation measures should therefore consider addressing boat type, density and speed. Moreover, stakeholder education, awareness raising and engagement activities should be undertaken for effective conservation results.
Yayın: New records of Cuvier’s beaked whales (Ziphius cavirostris) from the Turkish Levantine Sea.
Yazarlar: Aylin AKKAYA BAŞ, João Carvalho LAGOA, Elizabeth ATCHOI
Marine Mammals Research Association, Antalya, Turkey
Dergi: Turkish Journal of Zoology
Abstract: Cuvier’s beaked whales were sighted once on each of three different surveys over Antalya Canyon, in June and September 2015. Sightings took place in waters between 600 and 1000 m in depth and at 8 km from the closest shore. While the first sighting was positively identified as Cuvier’s beaked whale (Ziphius cavirostris (G. Cuvier, 1823)), latter sightings could not be identified to the species level. Nevertheless, noting that latter sightings had a similar spatial and temporal distribution to the first one and that there is an overwhelming difference between the probabilities of sighting Cuvier’s beaked whales versus Mesoplodon sp. in the Mediterranean Sea, all three sightings were assumed to be Cuvier’s beaked whales. Group size was recorded as two for the first two sightings and one for the last sighting. We hereby report the most recent Cuvier’s beaked whale sightings from the Levantine Basin and the first ones from Antalya Bay, as well as compile the previous sighting and stranding information on beaked whales in the eastern Mediterranean Sea. The current study supports previous modeling results showing the northern region of the Levantine Sea to be of importance to the species distribution in the Mediterranean Sea and we propose that the species is indeed regularly present in the area. However, consistent regional surveys are needed in order to validate these conclusions.