Aytac Altin

GÖKÇEADA ÇEVRESİNDE ZIPKIN İLE KILIÇ BALIĞI (Xiphias gladius) AVCILIĞININ MEVCUT DURUMU

Bu calismanin ana amaci 2015 yili kilic baligi av sezonunda Gokceada cevresinde zipkinla avcilik yapan teknelerin teknik ozelliklerinin belirlenmesi ve sezon boyunca elde edilen toplam av ile birim av (CPUE) miktarlarinin tespit edilmesidir. Teknelerin teknik ozelliklerinin belirlenmesi icin anket calismasi uygulanmistir. Avlanan balik miktarlari (yakalanan balik sayisi ve agirliklari) ise sezon boyunca kayit altina alinmistir. Kilic baligi av sezonunda boylari 8 m ile 15 m, motor guclerinin ise 75 hp ile 450 hp arasinda degisen 20 balikci teknesi Gokceada limanlarina baglanarak avcilik gerceklestirmislerdir. Kilic baligi avcilik faaliyetlerinin 100 - 1000 m arasindaki derinliklerde ve ozellikle 3 bolgede yapildigi tespit edilmistir. Kilic baligi avciligi yapan teknelerin 2015 av sezonunda ortalama 25 gun denize ciktiklari belirlenmistir. Toplam 463 adet balik yakalanmis olup, tekne basina ortalama CPUE (adet/gun) ise 0,88 olarak hesaplanmistir. Gokceada’da karaya cikarilan balik miktari 11731,83 kg olarak tespit edilmistir. Gerceklestirilen bu avciligin ekonomik degerinin 400162.87 TL oldugu hesaplanmistir. Anahtar Kelimeler: Kilic Baligi , Xiphias gladius, Zipkin, Kuzey Ege Denizi

Gökçeada çevresinde zıpkın ile yakalanan kılıç balıklarının (Xiphias gladius) yaş ve büyüme özellikleri

Bu calismada Kuzey Ege Denizinde 24 Mart – 15 Haziran 2015 tarihleri arasinda zipkin ile yakalanan ve Gokceada’da karaya cikarilan kilic baligi, Xiphias gladius bireylerinin yas ve buyume ozellikleri belirlenmistir. Alt cene catal boylari (LJFL) 70 ile 174 cm ve agirliklari 4 – 69 kg arasinda olan toplam 300 adet kilic baligi analizlerde kullanilmistir. Boy – agirlik iliskisi W = 5E-06L3,188 (R2 = 0,948) olarak hesaplanmistir. Toplam 83 adet bireyden anal yuzgec isinlari kullanilarak yas tayinleri gerceklestirilmistir. Yapilan yas tayinleri sonucunda, kilic baliklarinin 0 - 5 yas arasinda olduklari ve en fazla bireyin 2 yasinda oldugu tespit edilmistir. Von Bertalanffy buyume denklemi L∞ = 218,3; k = 0,193 ve t0 = -2,1031 olarak hesaplanmistir

Daily growth rates and hatch date distributions of common two-banded seabream, Diplodus vulgaris inhabiting the Çanakkale shallow waters of Turkey

Otolith microstructure analysis was used to determine daily age, growth rate and hatching periods of young of the year (YOY) common two-banded seabream, Diplodus vulgaris, collected at two sites by using beach seine from Canakkale shallow waters between January and December 2007. Total length of the YOY D. vulgaris was between 12 and 86 mm and the daily ages ranged between 42 and 313 days. Somatic growth rate estimated by fitting a linear regression to the age–length data set was calculated as 0.273 mm day. According to the length–age regression analysis, maximum daily growth rates were found 0.277 mm day in the lowest sea temperature period and minimum values of 0.274 mm day were observed in the declining sea temperature period. Analysis of covariance indicated that there were no significant differences in the linear growth equations for the two cohorts (F 1⁄4 0.4008, P 1⁄4 0.527). Hatching period of the YOY was estimated to occur between October and March with relatively higher frequency in January. This study has shown that YOY D. vulgaris is a winter spawner in the Canakkale shallow waters.

FEEDING HABITS OF THE MARBLED GOBY, POMATOSCHISTUS MARMORATUS (ACTINOPTERYGII: PERCIFORMES: GOBIIDAE), IN THE ÇANAKKALE STRAIT, NORTHERN AEGEAN SEA, TURKEY

Pomatoschistus marmoratus (Risso, 1810) is a small demersal fish and one of the dominant species inhabiting shallow waters of the Mediterranean. Information, however, on their feeding habits are still scarce. In this study, the stomach contents of P. marmoratus were investigated in order to determine feeding habits accord - ing to seasons and sizes. The fish were collected monthly from 3 stations between October 2008 and August 2009, using a beach seine, from the shallow waters of the Canakkale Strait, Turkey. A total of 383 P. marmora - tus , ranging from 13 to 69 mm TL, were analysed. The most important prey items in the stomach contents were copepods and amphipods. The numerical abundance of each food item in the stomach contents varied significant - ly with season. The diet of juvenile P. marmoratus consisted mainly of copepods. The occurrence of largest prey items such as amphipods and bivalves appeared relatively higher in adults. However, no significant differences were found between the feeding habits of juveniles and adults .

The diet of Clinitrachus argentatus (Blennioidei: Clinidae) in the northern Aegean and Marmara Seas.

Differences in the diet composition of small (28-42 mm total length, L(T)) and large (43-75 mm L(T)) individuals of the cline Clinitrachus argentatus (Clinidae) were evident. Smaller individuals preyed mainly on copepods, whereas larger individuals ate mainly amphipods, isopods, brachyurans and polychaetes.