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Bu çalışmada, Kuzey Ege Denizi'nde (Saroz Körfezi) Fangri balığının toplam boy (TL) ile toplam ağırlık (TW) arasındaki ilişki, yaş, büyüme ve otolit boyu (OL) -otolit ağırlığı (OW), balık boyu (TL) -otolit boyu (OL), balık ağırlığı (TW) -otolit boyu (OL), otolit boyu (OL) -otolit genişliği (OWi) arasındaki morfometrik ilişkiler incelenmiştir.

The angular roughshark, Oxynotus centrina (Linnaeus, 1758), is a rarely encountered deep-sea demersal shark species. It is listed as "Critically Endangered" in the IUCN's regional assessment for the Mediterranean. Like other sharks and rays, the angular roughshark is subject to by-catch in demersal trawl and longline fisheries. This study contributes new knowledge on (a) its occurrence, size and sex information; and (b) its feeding ecology in the Sea of Marmara. Data were collected on total length (TL), total weight (TW) and sex from unpublished research survey reports performed intermittently from 1994 to 2020. According to the data, O. centrina was mainly recorded from the muddy sand bottom type in the southwest region of the Marmara Sea, which has higher biodiversity of macrobenthic species than other regions. Different methodological approaches were conducted to understand its feeding, such as DNA metabarcoding and isotope analysis to identify its prey spectra and assign a trophic level. Sampled specimens were full of liquid in their stomachs without any discernible visually identifiable prey items. The metabarcoding analyses were also unsuccessful in identifying any prey items. Trophic position calculation based on nitrogen isotope in muscles highlighted that O. centrina has the highest trophic position compared to the other sharks and rays in the Sea of Marmara. Although it was found mainly feeding on polychaetes and sipunculids species from previous studies, the δ 15 N values made the authors cautious about the possibility of this species feeding on low trophic-level benthic invertebrates. Because the authors could not observe the presence of shark vitellus in the stomachs and could not succeed in DNA identification for prey, this study highlights high δ 15 N values similar to top predators for O. centrina. The authors conclude that this species strategically feeds mainly on shark eggs to fulfil its nutritional requirements with minimum energy expenditure in line with its slow-moving behaviour and mouth morphology.

Gul G., Ismen A., Arslan M. 2014. Age, growth, and reproduction of Dentex maroccanus (Actinopterygii:Perciformes: Sparidae) in the Saros Bay (north Aegean Sea). Acta Ichthyol. Piscat. 44 (4): 295-300.Background. The Morocco dentex, Dentex maroccanus Valenciennes, 1830, is a sparid species, which has economical value and its population is expanding in a 20-500 m depth range throughout the Mediterranean. Worldwide, there is a lack of information about the biology (age, growth, reproductive season, first maturity length) of this species. This study provides the first data on population parameters of D. maroccanus in the Aegean Sea. Conclusion.Results reported in this work will contribute to the knowledge on the biology of D. maroccanus in the north Aegean Sea and also to a better understanding of its role in the marine ecosystem.

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Trophic ecology studies on predator-prey interactions reveal insights into ecological communities and help understand a species' role in the food web by contributing to improved fisheries management and conservation capabilities. Understanding the ecological role of overexploited and endangered predators is essential to deciphering how their feeding behaviour influences food web dynamics. In this study, the authors investigated the feeding behaviour of the common and IUCN-listed Near Threatened (NT) thornback ray Raja clavata, using carbon and nitrogen stable isotope and stomach content analysis (SCA). It has recently suffered an 87% decline in reported catches from the Sea of Marmara within the last decade. These results show that thornback ray mainly feeds on teleost species, except in summer, with both methods showing this species changes its diet ontogenetically by SCA. This ontogenetic diet shift was at lengths 40-50 cm by changing group preferences from Crustacea to Teleostei. MixSIAR results showed that both adult and juvenile individuals of R. clavata feed mainly on the crustaceans, but the contribution of teleosts represented by Trachurus sp. was very low (<15%). The trophic position increased total length and was higher than other batoid species in the Sea of Marmara.