No abstract

Demersal fish fauna of the Sea of Marmara, Turkey was determined by bottom trawl surveys between March 2017-December 2018 at 34 stations with the monthly samplings. During the study, a total of 61 teleost and 12 cartilaginous fish species belonging to 42 families were sampled. The target, bycatch and discard rates of CPUE were determined as 13.40%, 69.64% and 16.95%, respectively. In total, 53.9% of the CPUE was stemmed from Trachurus trachurus. Mustelus mustelus, Raja clavata, Merluccius merluccius and Merlangius merlangius had the highest CPUE with a mean of 77.63, 71.86, 71.72 and 72.68 kg/km 2 , respectively. The highest biodiversity was observed in the southwestern part of the Marmara Sea. With increasing depth, the species number of the teleost fish decreased, whereas the species number of the cartilaginous fish increased. The mean CPUE values of the economical demersal fish species were lower in comparison to those reported from other regions in Turkey. Evidence suggests fish stocks with shallower distribution is under heavier threat against fishing pressure. Since commercial trawling is banned in the Sea of Marmara, beam trawl fishery can be considered as the major threat to demersal fish stocks in the region.

: The aim of this study was determining of some population parameters of Spicara maena in the Sea of Marmara and North Aegean Sea. Samples of S. maena were collected from commercial fishing, gillnet/trammel net and line fishing, between February-October 2013 in the Northern Aegean Sea (Dikili, Altınoluk, Küçükkuyu) and the Sea of Marmara (Karabiga, Bandırma, Tekirdağ). A total of 323 S. maena specimens were analysed. The total length of the specimens ranged from 8.4 to 18.8 cm. The length-weight relationships for the Sea of Marmara and the Northern Aegean Sea were a=0.0030, b=3.53, SEb=0.080 and a=0.0100, b=3.06, SEb=0.120 respectively. The b values showed that the growth of S. maena in the Northern Aegean Sea was isometric while the sample in the Sea of Marmara showed positively allometric growth. Fish aged 1-4 years in the Sea of Marmara and 2-6 years in the North Aegean Sea were present in the samples.Growth in length including both sexes was expressed using the von Bertalanffy equation, L ∞ =17.17 cm, k=0.52 y, t0=-1.04 y -1 in the Sea of Marmara and L ∞ =18.71 cm, k=0.35 y, t0=-1.98 y -1 in the Northern Aegean Sea. The otolith length-total length relationships in the Sea of Marmara and the Northern Aegean Sea were OL=0.301×TL+1.049 and OL=0.249×TL+1.885, respectively.

No abstract

Bu çalışmada Marmara Denizi'nin biyoçeşitliliği ve Derinsu Pembe Karidesi av miktarları belirlenmiştir. Örneklemeler Ekim 2011-Temmuz 2014 tarihleri arasında mevsimlik olarak gerçekleştirilmiştir. Marmara Denizi balıkçıların av sahaları dikkate alınarak 6 bölge değerlendirilmiştir: Erdek açıkları, Tekirdağ, Marmara Adası, Kapıdağ, Yalova ve Silivri. Toplamda 6 grup altında 90 farklı tür elde edilmiştir; kemikli balıklar (42) kıkırdaklı balıklar (7), kabuklular (12), çift kabuklu yumuşakçalar (8), kafadanbacaklılar (5), derisidikenliler (10) ve diğer omurgasızlar (6). Margalef tür zenginliği (d), Shannon çeşitlilik (H') ve Pielou'nun düzenlilik (J) indeksleri hesaplanmıştır. Benzerlik diyagramları mevsimlere, bölgelere ve derinliklere göre hazırlanmıştır. Mevsimlere göre ekolojik indeks değerleri kış periyodunda yüksek bulunmuştur. Bölgelere göre en yüksek tür çeşitliliği 1. (Erdek açıkları) ve 5. (Kağıdağ) bölgede, en düşük çeşitlilik 6. (Silivri) bölgede bulunmuştur. Benzerlik diyagramına göre bölgelerin %57 oranında benzer oldukları görülmektedir.