Onur Gönülal

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.

Comparison and origins of polycyclic aromatic hydrocarbons (PAHs) in the entrance and the exit of the Turkish Straits System (TSS)

Investigations of total petroleum hydrocarbons (TPHs) in water and polycyclic aromatic hydrocarbons (PAHs) in sediments were performed in the entrance and the exit of the Turkish Straits System (TSS) in autumn of 2016 and spring of 2017. TPH and PAH values ranged from 1.7 to 11.6 μg/l and 120 to 2912 ng/g (dw), respectively. On the basis of the given surface fluxes of the TSS, average petroleum flows were calculated as 1631 t/y from the Black Sea to the Marmara Sea and 8484 t/y from the Marmara Sea to the Aegean Sea. Pollution by PAHs ranged from relatively moderate to high. The most polluted sediments were collected from regions affected by shipping, such as Riva and Seddülbahir located at the entrance and the exit of the TSS, respectively. Moreover, origins of PAHs were determined using the ratios of PAH congeners. The main origins of PAHs were found as both pyrolytic and petrogenic at most stations.

Abundance and composition of marine litter around Gökçeada Island (Northern Aegean Sea)

Marine debris are frequently studied on beaches and occasionally in coastal waters, but links between these two environments have rarely been studied. Litter items were collected by hand in the Gökçeada beaches supralittoral zone, consisting of sandy or rocky beaches, and collected from subtidal areas between 50–450 m depth range on the continental shelf with bottom trawling. Collected litter were sorted and categorized by type, usage and origin. On the beaches, litter density varied from 0.1 to 22.1 items per 100 m2. Plastic materials dominated the composition of waste materials (59%) followed by soft plastic, nylon (11.5%). Eight percent of litter was of foreign in origin coming from two countries (Greece and Bulgaria). Offshore, during 32 hauls only 12 items were collected, and the number of debris ranged from 0 to 1.6 items km−2. Gökçeada Island should be further monitored in order to develop regional marine litter management solutions.

New records of decapod crustaceans from the deep Aegean Sea of Turkey

The northern Aegean Sea is one of the most poorly studied areas of the Mediterranean. Decapod crustaceans have been consistently studied, mainly from a systematic point of view, but existing information on the deep Aegean Sea still proves to be rather limited and also scattered over many smaller, primary publications. Yet, many studies have been carried out on decapod crustaceans of the Turkish seas since the 1960s. Two detailed lists of decapod species found along the Turkish coast were presented by Kocataş & Katağan (2003) and Ateş et al. (2010). In the past, only few, mainly French and Russian, expeditions visited the deep eastern Mediterranean Sea. Albartelli et al. (1990) carried out the first quantitative investigation in the deep Aegean Sea in 1989, as did Sokolova et al. (2001) in 1992 in the eastern Levantine Sea. The macrofauna communities of the Cretan slope down to 1600 m depth have been investigated since 1990 (Tselepides & Eleftheriou, 1992; Karakassis & Eleftheriou, 1997; Duineveld et al., 2000). The first quantitative investigations in the Levantine Sea down to depths exceeding 4000 m were made during the “Meteor” cruise in January 1987, which was carried out for taxonomic purposes (Müller, 1989). The main objectives of the present paper are to provide new information on the decapod fauna of the deep Aegean Sea. Indeed, the study of the deep sea off the northern region of Turkey called Gökçeada, added new data on decapod crustaceans for the Aegean Sea. The benthic samplings yielded Gennadas elegans (Smith, 1882) and Pandalina profunda Holthuis, 1946, that are reported for the first time from the Aegean Sea off the Turkish coast, while Monodaeus guinotae Forest, 1976 and Odontozona