Bayram Öztürk

Persistent organochlorine residues in harbour porpoise (Phocoena phocoena) from the Black Sea

A wide range of organochlorine residues were determined in the blubber of harbour porpoises from the Black Sea. Concentrations of DDTs (8.3–180 μg g−1 wet weight) were the highest followed by PCBs (1.6–39 μg g−1), HCHs (1.5–17 μg g−1), CHLs (0.11 – 2.4, μg g−1) and HCB (0.057 – 0.61 μg g−1). The composition of DDT and its metabolites was in the order of p,p′-DDT (46%), ac>t-DDD (34%), p,p′-DDT (16%) and o,p′-DDT (4%). A similar pattern was also observed in fish from the Black Sea. Relatively higher concentrations of p,p′-DDD in these animals suggested the reductive condition of the Black Sea resulting from organic waste pollution. The residue levels of organochlorines were lower in older female porpoises possibly due to lactational transfer of these contaminants to their calves, while in males the organochlorine concentrations were positively correlated with age. When compared with other cetaceans, the organochlorine residues in harbour porpoises showed a perceptible male-female difference. It is noteworthy that the contamination by DDTs and HCHs in the Black Sea harbour porpoises were elevated amongst a worldwide comparison of organochlorine residues in the same species.

Genetic and historic evidence for climate-driven population fragmentation in a top cetacean predator: the harbour porpoises in European water

Recent climate change has triggered profound reorganization in northeast Atlantic ecosystems, with substantial impact on the distribution of marine assemblages from plankton to fishes. However, assessing the repercussions on apex marine predators remains a challenging issue, especially for pelagic species. In this study, we use Bayesian coalescent modelling of microsatellite variation to track the population demographic history of one of the smallest temperate cetaceans, the harbour porpoise (Phocoena phocoena) in European waters. Combining genetic inferences with palaeo-oceanographic and historical records provides strong evidence that populations of harbour porpoises have responded markedly to the recent climate-driven reorganization in the eastern North Atlantic food web. This response includes the isolation of porpoises in Iberian waters from those further north only approximately 300 years ago with a predominant northward migration, contemporaneous with the warming trend underway since the ‘Little Ice Age’ period and with the ongoing retreat of cold-water fishes from the Bay of Biscay. The extinction or exodus of harbour porpoises from the Mediterranean Sea (leaving an isolated relict population in the Black Sea) has lacked a coherent explanation. The present results suggest that the fragmentation of harbour distribution range in the Mediterranean Sea was triggered during the warm ‘Mid-Holocene Optimum’ period (approx. 5000 years ago), by the end of the post-glacial nutrient-rich ‘Sapropel’ conditions that prevailed before that time.

Isomer-specific analysis of polychlorinated biphenyls in harbour porpoise (Phocoena phocoena) from the Black Sea

Abstract The highly toxic coplanar PCBs and other isomers were determined in harbour porpoises and fish (porpoise diet) collected from the Turkish coastal water of the Black Sea, during 1993. The concentrations of total PCBs were found in the range of 5.0–34 μg g−1 wet wt in the blubber of porpoises. Highly chlorinated members such as IUPAC Nos 138, 153 and 180 were the dominant congeners, consisting of 41% of the total PCB concentrations. The mean total 2,3,7,8-TCDD toxic equivalents (TEQs) of 13 coplanar PCBs including non-, mono- and di-ortho congeners were 1400 pg g−1 wet wt in the blubber of males and 300 pg g−1 wet wt in females. The IUPAC No. 118 was the most contributing congener occupying about 60% of the total TEQs. The most toxic non-ortho chlorine substituted coplanar PCBs such as IUPAC No. 77, 126 and 169 were minor contributors and accounted for 7.8, 4.2 and 0.7%, respectively, of the total TEQs. The activities of PB and MC-type enzymes were found to be low in Black Sea harbour porpoises, suggesting long term accumulation and possible toxic effects of PCBs in this species.

Postglacial climate changes and rise of three ecotypes of harbour porpoises, Phocoena phocoena, in western Palearctic waters.

Despite no obvious barriers to gene flow in the marine realm, environmental variation and ecological specializations can lead to genetic differentiation in highly mobile predators. Here, we investigated the genetic structure of the harbour porpoise over the entire species distribution range in western Palearctic waters. Combined analyses of 10 microsatellite loci and a 5085 base‐pair portion of the mitochondrial genome revealed the existence of three ecotypes, equally divergent at the mitochondrial genome, distributed in the Black Sea (BS), the European continental shelf waters, and a previously overlooked ecotype in the upwelling zones of Iberia and Mauritania. Historical demographic inferences using approximate Bayesian computation (ABC) suggest that these ecotypes diverged during the last glacial maximum (c. 23–19 kilo‐years ago, kyrbp). ABC supports the hypothesis that the BS and upwelling ecotypes share a more recent common ancestor (c. 14 kyrbp) than either does with the European continental shelf ecotype (c. 28 kyrbp), suggesting they probably descended from the extinct populations that once inhabited the Mediterranean during the glacial and post‐glacial period. We showed that the two Atlantic ecotypes established a narrow admixture zone in the Bay of Biscay during the last millennium, with highly asymmetric gene flow. This study highlights the impacts that climate change may have on the distribution and speciation process in pelagic predators and shows that allopatric divergence can occur in these highly mobile species and be a source of genetic diversity.

Abundance and composition of solid waste materials on the western part of the Turkish Black Sea seabed

Accumulation of marine litter is a worldwide growing problem of pollution in seas. Although it is recognized as one of the major pollution types for the Black Sea, very few studies can provide quantitative data and there are no data at all on solid wastes of the Black Sea seabed. This study was therefore aimed at investigating the abundance and composition of solid wastes in the southwestern Black Sea. Litter items were collected by trawling in October 2007, and in February and April 2008, at depths ranging from 25 m to 100 m. The solid waste concentration on the seabed showed a large variability (with zones ranging from 128–1320 items km– 2 and 8–217 kg km-2). Marine litter concentrations were higher than in the Mediterranean Sea, consisting mainly of plastic materials. Most items were fragmented, which indicated that they had spent a long time at sea, and this made their identification difficult. Only 8 items had legible labels, 2 of them being Turkish and 6 foreign. This suggested that marine litter is a trans-boundary problem, not only in the oceans, but also for enclosed seas like the Black Sea. The situation needs to be monitored all over the basin using standardised methods in order to develop regionally valid and effective solutions.

The Marmara Sea, a Link between the Mediterranean and the Black Sea

The Marmara Sea represents a unique ecosystem between the Black and Mediterranean Seas due to its hydrographical peculiarities. This sea is one of the busiest water ways in the world. There are 11 exotic species found in the Marmara Sea. These are Codium fragile, Mnemiopsis leidyi, Beroe cucumis, Rapana venosa, Scapharca inaequivalvis, Mya arenaria, Teredo navalis, Penaeus japonicus, Callinectes sapidus, Mugil so-iuy and Gambusia affinis. Among them, R. venosa has been commercially important and M. leidyi is the most destructive species for the native species.

Spatially Explicit Analysis of Genome-Wide SNPs Detects Subtle Population Structure in a Mobile Marine Mammal, the Harbor Porpoise.

The population structure of the highly mobile marine mammal, the harbor porpoise (Phocoena phocoena), in the Atlantic shelf waters follows a pattern of significant isolation-by-distance. The population structure of harbor porpoises from the Baltic Sea, which is connected with the North Sea through a series of basins separated by shallow underwater ridges, however, is more complex. Here, we investigated the population differentiation of harbor porpoises in European Seas with a special focus on the Baltic Sea and adjacent waters, using a population genomics approach. We used 2872 single nucleotide polymorphisms (SNPs), derived from double digest restriction-site associated DNA sequencing (ddRAD-seq), as well as 13 microsatellite loci and mitochondrial haplotypes for the same set of individuals. Spatial principal components analysis (sPCA), and Bayesian clustering on a subset of SNPs suggest three main groupings at the level of all studied regions: the Black Sea, the North Atlantic, and the Baltic Sea. Furthermore, we observed a distinct separation of the North Sea harbor porpoises from the Baltic Sea populations, and identified splits between porpoise populations within the Baltic Sea. We observed a notable distinction between the Belt Sea and the Inner Baltic Sea sub-regions. Improved delineation of harbor porpoise population assignments for the Baltic based on genomic evidence is important for conservation management of this endangered cetacean in threatened habitats, particularly in the Baltic Sea proper. In addition, we show that SNPs outperform microsatellite markers and demonstrate the utility of RAD-tags from a relatively small, opportunistically sampled cetacean sample set for population diversity and divergence analysis.

T-PAH contamination in Mediterranean mussels (Mytilus galloprovincialis, Lamarck, 1819) at various stations of the Turkish Straits System

Mussels (Mytilus galloprovincialis) from the Turkish Straits Systems were analyzed for sixteen parent polycyclic aromatic hydrocarbon (PAH) contents by high performance liquid chromatography (HPLC). This marine organism was selected because of its multitude, wide distribution, being bio indicator for the pollution and consumption by humans. Total PAH concentrations ranged from 1.2 to 589 μg g(-1) in Istanbul Strait, 0.94-36.4 μg g(-1) in Marmara Sea and 0.4-47.9 μg g(-1) in Çanakkale Strait during the samplings. According to the results Istanbul and Çanakkale Straits are more polluted than the Marmara Sea.

Stranding of a Green Turtle, Chelonia mydas (Linnaeus, 1758), in the Turkish Black Sea

& SIMMONS 1980, GLUTZ VON BLOTZHEIM & BAUER 1989), and other parts of Transcaucasia. Georgia has an estimated 10-50 breeding pairs, where a small colony was discovered on Javakheti Plateau (GÁLVEZ et. al. 2005). No recent breeding record is known for Armenia (ANANIAN, pers. comm.), although ADAMIAN & KLEM (1999) listed the species as a rare breeding species. I assume that this breeding occurs irregularly in Azerbaijan and in low numbers, and may have been overlooked in the past because of the low density of observers.

Diversity and bathymetric distribution of decapod crustaceans attracted to baited traps from the middle slope of the northern Aegean Sea

We sampled the decapod crustaceans inhabiting the depth zone between 500 and 1500 m off Gokceada Island (northern Aegean Sea) from May 2010 to November 2011. The deep-slope decapod fauna of the northern Aegean Sea was sampled with baited traps. A total of 23 species of decapods have been identified at 32 stations. The results were analysed in terms of composition and distribution of benthic and benthopelagic bait-attracted species between regions. In addition, they were compared between stations in relation to the depth gradient. The results are discussed in relation to previous studies carried out in the eastern and western Mediterranean. Also, the use of traps is commented for different regions and the effects of the sampler on benthic species are discussed. The most common species was the penaeid shrimp, Parapenaeus longirostris in samples taken between 500 and 600 m. It is followed by Polycheles typhlops and the pandalid shrimp Plesionika martia martia. These species constitute more than 50% of all decapods. Differences among the strata at 500-1500 m depth were tentatively explained using the Shannon-Weaver diversity index (H′). The highest H′ value was found for the 800-1000 m depth strata. The lowest number of species was observed between 1000 and 1500 m, which lowered the diversity index values (H′). The results of similarity percentage analysis (SIMPER) showed a change in the decapod fauna below 1000 m depth. The present results are preliminary; further data collection and analysis will be required to evaluate the role of palaeoecolgical conditions and trophic factors, and how these could be supposed to interact.