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AbstractThe bottlenose dolphin is a widely distributed species found in temperate waters, including the Mediterranean and Black Seas. The Black Sea population is recognized as a distinct subspecies, Tursiops truncatus ponticus, due to genetic and morphological differences. This study analyzed mitochondrial DNA (mtDNA) sequences of 73 bottlenose dolphin samples collected between 1999 and 2016 along the Turkish Black Sea coast, Turkish Straits System (TSS), Aegean, and Mediterranean Seas revealing 14 haplotypes, eight of which are reported here for the first time.The haplotype network shows two main nodes with star-like sub-networks, but no apparent geographic pattern. The lack of geographical groupings of haplotypes indicates the high mobility of the species within the sampled area. The northern Black Sea bottlenose dolphins (NBS) appear to be genetically differentiated from those in the southwestern Black Sea (SBS), Mediterranean, and Atlantic Ocean, but not from the TSS and Aegean Sea populations. Besides, SBS bottlenose dolphins were differentiated only from those in the western Mediterranean (WM) and the Atlantic. Therefore, NBS and SBS bottlenose dolphins should at least be categorized as different populations. However, contrary to some previous studies there was no evidence supporting the classification of Black Sea bottlenose dolphins as a separate subspecies.The TSS differs only from the Atlantic and the Aegean, and functions like a migratory ‘melting pot’ for surrounding populations. Despite the largest sample size, NBS bottlenose dolphins exhibited the lowest haplotype and nucleotide diversity. This low genetic diversity and potential isolation from adjacent populations highlight the need for prioritizing the conservation of NBS bottlenose dolphins. [ABSTRACT FROM AUTHOR]

The Black Sea is a semi‐enclosed inland sea with an unevenly distributed extensive coastal shelf area and anoxic deep waters. It is inhabited by common and bottlenose dolphins, as well as harbour porpoises, all represented by local subspecies. Between September 2020 and October 2022, 19 F‐PODs deployed by research teams from Bulgaria, Georgia, Romania, Türkiye and Ukraine collected data on acoustic activity of Black Sea harbour porpoises. Strong seasonal and diel patterns were found, which varied in three regions. In the south‐eastern part of the Black Sea, harbour porpoise acoustic activity was higher from January to May, with a peak in April. This pattern agrees with the seasonal anchovy migration from the winter spawning grounds in warmer waters in the south‐eastern region to feeding grounds on the productive shallow north‐west shelf. The diel pattern showed strong nocturnal acoustic activity, which is consistent with anchovy vertical migration. Porpoises on the western side of the Black Sea exhibited a bimodal seasonal pattern in acoustic activity, with a larger peak in April and a smaller one in October. Diel activity was primarily nocturnal. On the north‐west shelf, harbour porpoise acoustic activity was mostly recorded during the warm period from April to October. The diel pattern showed activity mainly during daylight with two peaks: a smaller one approximately at dawn and a larger one at dusk. This pattern is similar to the vertical migrations of sprat. Overall, the results of the study were consistent with the prey being an important driver of seasonal and diel dynamics of harbour porpoise acoustic activity. [ABSTRACT FROM AUTHOR]

Introduction: Population abundance is amongst the most basic and crucial parameters for the assessment of conservation status of any species. Three species of odontocetes, all represented by local subspecies, inhabit the Black Sea: the Black Sea common dolphin Delphinus delphis ponticus, the Black Sea bottlenose dolphin Tursiops truncatus ponticus, and the Black Sea harbour porpoise Phocoena phocoena relicta. Their populations are threatened by multiple factors, including overfishing of their prey, bycatch, pollution and epizootics. Despite this, there are no basin wide estimates for any cetacean species in the Black Sea. Methods: In 2019, a systematic study was carried out under the EU CeNoBS project. Six strata were designed in the waters of Bulgaria, Georgia, Romania, Türkiye and Ukraine, covering most of territorial and offshore waters, which were surveyed between June 19 and July 4. A line transect distance sampling approach was used, following predefined transects within each stratum, achieving a 5% coverage of the surveyed area. A total of 7,344 kilometres of transects were surveyed recording a total of 1,744 cetacean sightings. Design-based abundance estimates were obtained using a Multiple Covariate Distance Sampling (MCDS) approach. Model-based abundance estimates were also derived using a Generalized Additive Models (GAM) approach, linking species sightings with a number of environmental covariates (e.g., bathymetric features, sea surface temperature, chlorophyll-a) over a grid of 10x10 km. Results and discussion: The uncorrected (for perception and availability bias) estimates obtained through the model-based analysis were 108,283 (CV=0.07) common dolphins, 22,720 (CV=0.15) bottlenose dolphins and 93,808 (CV=0.06) harbour porpoises. These aerial surveys yielded the first insights on overall abundance, density and distribution, providing current regional baseline values and density maps for all three cetacean species of the Black Sea during the summer months, to be used for the elaboration of effective conservation measures and to address national and international requirements. [ABSTRACT FROM AUTHOR]

The first observation of epimeletic behaviour of a bottlenose dolphin (Tursiops truncatus) was reported from the Marmara Sea, Türkiye. This behaviour was observed between an adult 'caregiver' of undetermined sex and a dead individual identified as an adult male based on images captured during the observation. The former individual did not leave the dead one's side for at least six days between 26 and 31 March 2024 over the distance of 7 km between Zeytinburnu and Yeşilköy, close to the south entrance of the İstanbul Strait in the Marmara Sea. When approached by a boat, the dolphin was seen to push the dead one away from the boat by attaching its dorsal fin to the dead one's fins or pushing with its head. Only 7 of the 96 recorded cases were among subadults or adults cetaceans in world oceans, and only two of these did not show sexual behaviour as in this case. This first and rare observation is a significant addition to our understanding of the behaviour of cetaceans in this region. [ABSTRACT FROM AUTHOR]

This short communication reports an observation of a leatherback turtle Dermochelys coriacea in the İstanbul Strait (Bosphorus), Marmara Sea, on 9 July 2024. Leatherback turtles are occasionally reported in the Aegean and Mediterranean Seas of Türkiye. This is the northernmost record of the leatherback turtle in the Mediterranean Basin. As the importance of citizen science becomes more apparent and public awareness grows, access to observational information such as this will increase through digital technologies. [ABSTRACT FROM AUTHOR]

Cuvier's beaked whales, Ziphius cavirostris, one of the regular cetacean species of the Mediterranean Sea, are affected by underwater noise, mainly shipping, naval exercise and seismic operations worldwide. Between 9 February - 6 March 2023 but mostly in 9-10 February, at least 13 beaked whales stranded in the northwest and west of the Cyprus Island in the eastern Mediterranean Sea. This study presents the preliminary findings of necropsy, histopathology and virology of six individuals and compiles information on the present human threats in the region at the time of the incident. Histopathological findings did not provide a clear result. However, intense congestion was seen in both macroscopic and histopathological examinations. The presence of undigested fresh squid in the stomach is an indicator of sudden death. Besides, intravascular gas bubbles in macroscopic examination were in line with the general findings in previous studies on beaked whale strandings after they had died due to military exercises. As a precautionary approach, activities generating impulsive underwater noise need to follow the ACCOBAMS Mitigation Guideline and if not they should halt particularly in areas where cetaceans presence is known. In a further note, all the Parties of ACCOBAMS are expected to refrain from conducting naval exercises involving sonar or underwater bursts near "Areas of Particular Concern for Beaked Whales", taking into account the ACCOBAMS resolution 5.13 of 2013 and urges the implementation of underwater noise mitigation strategies in the fragile habitats of the eastern Mediterranean Sea. [ABSTRACT FROM AUTHOR]

Identification of key habitats of migratory marine megafauna species is of great importance, especially for the conservation of threatened species. In this study, the occurrence and distribution of sea turtles in coastal and offshore areas were investigated for the first time by offshore onboard observations in the Finike Seamounts (Anaximander) Specially Protection Area and its adjacent waters. The study was carried out in spring and autumn in 2021 and two sea turtle species known to breed in Türkiye, the loggerhead turtle (Caretta caretta) and the green turtle (Chelonia mydas) were observed. Of the total of 11 individuals observed, five of them were identified as the loggerhead turtle and two were identified as the green turtle. The species of four individuals could not be determined. The detection of individuals both during and after the breeding period for both species indicates that the Finike Seamounts Specially Protection Area and adjacent waters host sea turtle species throughout the year. The results of the study show that coastal and offshore observations should be continued systematically in order to make conservation measures specific to the region and to determine the abundance of both species in the region. [ABSTRACT FROM AUTHOR]

This article reports pelagic fish species recorded during the survey of cetaceans in the Finike Seamounts region and the adjacent waters in 2021. The Mediterranean flyingfish Cheilopogon heterurus (Rafinesque, 1810) and Atlantic bluefin tuna Thunnus thynnus (Linnaeus, 1758) were observed and recorded during their flight/leap movements on the water surface. The scientific sharing of these data is important in terms of emphasizing the richness of the pelagic life of the Finike Seamounts region and underlines the importance of declaring the region as a Special Environmental Protection Area (SEPA). [ABSTRACT FROM AUTHOR]

This is the first study regarding offshore seabird sightings in Turkish waters. The survey was carried out in Finike Seamounts (Anaximander) region and adjacent waters for 10 days in spring and seven days in autumn of 2021. Bird distributions were determined by visual observations that were carried out onboard R/V YUNUS-S with the standard line transect method. In total, 19 bird species belonging to seven Ordos and 11 Families were recorded. The first three dominant groups of species were Scopoli's shearwater (Calonectris diomedea, n: 92, 47%), and common tern (Sterna hirundo, n: 22, 11%), and common swift (Apus apus, n: 15, 8%). In the Turkish coastal and offshore region of the Mediterranean, migratory movements and distribution of bird species, mainly Ardeidae (Ciconiiformes) and Laridae, Sternidae, and Scolopacidae (Charadriiformes), were observed in spring and autumn. In this paper, the observed and anticipated migration routes were described for those species. Detailed and long-term studies over larger areas are recommended at offshore regions in Türkiye. [ABSTRACT FROM AUTHOR]

Three sperm whale (Physeter macrocephalus) strandings are reported from the Turkish Mediterranean coast between 2019 and 2020. The first individual was a juvenile found in July 2019 near Fethiye, in the west. The second individual, a neonate, stranded in Adana in the east, on 10 August 2020. The third case, a sub-adult/adult, stranded on the beach of Antalya, in the west on 14 August 2020. It was buried on the beach and excavated about two months later. During the excavation, a hard plastic food container was found, which contained cephalopod beaks and other plastics providing an opportunity for partial stomach content analysis. A total of 60 lower beaks were identified belonging to eight species. Umbrella squid Histioteuthis bonnellii was dominant, representing 30% of beaks encountered. Dry total weight of four plastics (hard plastic container, nylon bag, 1.5L PET bottle and packaging item) was 197.2 g. This opportunistic sampling allowed us to collect information on the stomach contents of this creature, which is rarely stranded on the Turkish and eastern Mediterranean coasts. Dietary studies on stranded marine animals are of great importance in monitoring environmental plastic levels and impacts on wildlife in this region. In the last 50 years, six sperm whales stranded on the Turkish coasts, five of them in the eastern Mediterranean Sea, which implies that this area is probably close to sperm whale habitats. Improvement of the stranding network as well as surveys for the distribution and abundance of this species to elaborate and implement effective conservation measures are recommended. [ABSTRACT FROM AUTHOR]

A stranding of a fin whale (Balaenoptera physalus) was reported for the first time from the Turkish coast of the northern Aegean Sea. A part of skeleton; posterior part of skull, a part of left mandible, ribs with mummified tissues of an individual were found in Saros Bay near Danişment village. The stranded whale was likely to be a juvenile as the estimated body size (13.5-14 m) was lower than the mature body size of those in the northern hemisphere. Although many parts of the specimen were missing and the exact date of the stranding was unknown, the information about such strandings of rare and threatened species like the fin whale is valuable in terms of understanding the regional distribution of the species. [ABSTRACT FROM AUTHOR]

A sighting of a group of false killer whale (Pseudorca crassidens) was reported for the first time in the northern Aegean Sea. It was also the first reported sighting in 25 years for the Aegean Sea. Eight individuals in total were recorded in a footage taken by a local fisherman. During the hauling of the handline, it was observed that one juvenile came to the line to play with it. The information of such sightings of rare species is valuable to understand the regional biodiversity. [ABSTRACT FROM AUTHOR]

This short communication reports an observation of unusual non-agonistic interactions between a juvenile harbour porpoise (Phocoena phocoena) and a group of bottlenose dolphins (Tursiops truncatus) in the Marmara Sea on 25 April 2015. [ABSTRACT FROM AUTHOR]

Genetic population structure of geographically isolated endangered Black Sea harbor porpoise (Phocoena phocoena relicta) is little known in Turkish waters, especially in the Turkish Straits System (TSS- Marmara Sea, Bosphorus and Dardanelles), which connects the Black Sea and the Aegean Sea. Mitochondrial DNA sequences of 70 new individuals sampled in the Turkish Black Sea, TSS and Aegean Sea, revealed five new haplotypes from the Black Sea. The findings support the idea that harbor porpoises from the Black Sea dispersed into the Aegean through the TSS. Considering signatures of population expansion, all subpopulations showed a signature of population expansion. The network data and the Фst calculations indicated that the Marmara Sea subpopulation was significantly differentiated from all of the other subpopulations, and supports the notion of its isolated. The finding of a potential management unit (MU) within an already heavily impacted subpopulation as a whole suggests that the individuals of P. p. relicta inhabiting the Marmara Sea require a very rigorous conservation strategy to ensure the survival of this subpopulation, represented by its unique haplotype. [ABSTRACT FROM AUTHOR]

Stomach contents of six striped dolphins taken as by-catch in the swordfish fishery in the eastern Mediterranean Sea off the Turkish coast were examined. In total, 29 taxa were identified to species or family and 1777 individual food items (1394 bony fishes, 289 cephalopods, 94 crustaceans) were counted. Diaphus spp. and Ceratoscopelus maderensis were the most remarkable ones, as they accounted for 70.45% of the total number of fishes. Onychoteuthis banksii, on the other hand, was the only cephalopod species found in all stomach content analyses and represented 38.06% of the total number of cephalopods. Bony fish species: Myctophum punctatum, Notoscopelus elongatus, Electrona risso, Sudis hyalina, Moridae sp., Phycidae sp., Sternoptychidae sp. and cephalopods: Pterygioteuthis giardi and Chtenopteryx sicula were reported the first time in the stomach contents of striped dolphin in the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

The Istanbul Strait (Bosphorus) is a part of the Turkish Straits System, connecting the Aegean Sea and the Black Sea. There are three cetacean species in the Strait, namely the harbour porpoise (Phocoena phocoena), the common dolphin (Delphinus delphis), and the bottlenose dolphin (Tursiops truncatus). To monitor the presence of the cetaceans, a fixed stereo passive acoustic monitoring system (A-tag) was deployed in the middle of the Strait from July 2009 to September 2010. In total 26,814 click trains were detected. Presence, direction and inter-click intervals of phonating cetaceans were measured. Most click trains were detected during the night time. Diel presence pattern was prominent in March and April. In spring, the cetaceans were concentrated in one specific direction from the fixed monitoring system. In contrast, they were found in all directions for the rest of the year. Short range sonar (inter-click intervals (ICIs) less than 50 ms) was commonly detected in spring. During the rest of the year ICIs could reach up to 150 ms. All these findings suggest that they were feeding or socializing in spring and mostly travelling in the other seasons. It is well known that pelagic fish such as sprat and bluefish start their migration from the Aegean Sea to the Black Sea in spring. This study suggests that the cetaceans use the middle part of the Strait for feeding on the pelagic fish in spring when the fish migration has just started. [ABSTRACT FROM PUBLISHER]

Between 1994 and 2012, 43 sightings of sperm whales (Physeter macrocephalus) were reported in the Turkish part of the Aegean and Mediterranean Sea. Most of the sightings were located near the Fethiye Canyon which is one of the deepest parts of the Mediterranean Sea. The eastern limit of the sperm whale sighting in the Turkish part of the Mediterranean Sea is Alanya and the northern limit is Gökçeada in the northern Aegean Sea. [ABSTRACT FROM AUTHOR]