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    Age, growth, and reproductive season of bluefish (Pomatomus saltatrix) in the Marmara region, Turkey
    (Oxford Univ Press, 2007) Ceyhan, Tevfik; Akyol, Okan; Ayaz, Adnan; Juanes, Francis
    Bluefish (Pomatomus saltatrix) are distributed widely along the Turkish coasts, and are regularly captured, especially in the Sea of Marmara during their spawning migration to the Black Sea from the Mediterranean in spring and during their return migration south in early autumn. Age, growth, and reproductive season are reported. The ages of 1114 bluefish were determined from otoliths. The age groups ranged from 0 to III, and mean fork lengths (and weights) were 14.4 +/- 0.12 cm (38.2 +/- 1.02 g), 19.5 +/- 0.06 cm (93.7 +/- 0.86 g), 27.5 +/- 0.48 cm (238.5 +/- 11.3 g), and 33.3 +/- 0.50 cm (431.9 +/- 17.08 g) for each age group, respectively. The von Bertalanfly growth parameters were L infinity = 51 cm, K = 0.228, and t(o) = -1.26 y. The reproductive period, evaluated from gonadosomatic indices, began in early spring and extended until August.
  • Küçük Resim
    Öğe
    Capture of a Blue Shark Prionace glauca (Linnaeus, 1758) (Chondrichthyes: Charcharhinidae) by a Swordfish Longliner off Fethiye (Mediterranean Sea, Turkey)
    (Çanakkale Onsekiz Mart Üniversitesi, 2020) Akyol, Okan; Ceyhan, Tevfik
    On 25 December 2012, a specimen of Prionace glauca (Linnaeus, 1758) was caught by a swordfish longliner along with 9 swordfish together off Fethiye at a depth of 1200 m. The specimen caught was measured as TL and weighed (kg), and photographed. The specimen was 85 cm TL and 7 kg. According to the previous studies, blue sharks especially observed abundantly in northern Aegean Sea, and can be accepted very rare incidental catch from the Turkish coasts owing to weak presuppose of swordfish fishery. However, there is an important place of blue sharks in the global fin trade area. Therefore, population trend of this shark species is swift decreasing.
  • Küçük Resim
    Öğe
    Güney Ege Kıyıları (Türkiye) Uzatma Ağları Balıkçılığında Egzotik Türler ve Birim Çaba Başına Düşen Av (CPUE) Miktarları
    (Çanakkale Onsekiz Mart Üniversitesi, 2022) Akyol, Okan; Ceyhan, Tevfik; Düzbastılar, F. Ozan; Ertosluk, Okan
    This study presents some exotic fish diversity and catch per unit effort values of exotic fish from gillnet fishery along the southern Aegean Sea. Lessepsian puffer fish (Lagocephalus sceleratus), lionfish (Pterois miles), squirrelfish (Sargocentron rubrum), rabbitfish (Siganus sp.) and a blue crab (Portunus segnis) were caught in the Aegean Sea. Rabbitfish and blue crab sell in the fish markets. Seasonally, the average CPUE of exotic fish was calculated to be 0.7 ± 0.3 kg.1000 m-1 in autumn in catch. This value indicated that it was 72 times lesser than the total seasonal CPUE.
  • [ X ]
    Öğe
    Marmara Bölgesi' nde lüfer (Pomatomus saltatrix L., 1766) avcılığında kullanılan alamana ağları
    (2005) Ceyhan, Tevfik; Akyol, Okan; Ayaz, Adnan
    Türkiye denizlerinde geniş bir dağılım gösteren lüfer balıklarının avcılığında alamana ağları özellikle Marmara bölgesinde yoğun olarak kullanılmaktadır. Galsama ve fanyalı olarak iki gruba ayrılan alamana ağlarında, 21 Od/3-4 numara 46-64 mm TGB'nda, 21 Od/9-12 no 250-280 TGB'nda fanyalar kullanılmaktadır. Alamana ağlarının toplam uzunlukları 265 ila 660 m arasında değişmektedir. Donam faktörü (E) 0,5 ve 0,67 dır. Bir ünitede (yaprakta) tor ağın yüksekliği 60-120 göz, fanyanın ise 5,5-13,5 göz arasındadır. Bir takım alamana ağı 3 ila 8 ünite yükseklikte olabilmektedir.
  • [ X ]
    Öğe
    The encircling nets, used in bluefish (Pomatomus saltatrix L., 1766) fishery in Marmara Region
    (Ege Univ, 2005) Ceyhan, Tevfik; Akyol, Okan; Ayaz, Adnan
    Encircling nets, especially used densely in Marmara Region, are used for fishery of bluefish which are widely distributed in Turkish seas. Two types encircling nets (gill net and trammel net) are contained 210d/3-4 no thickness for fine-meshed net which have 46-64 mm mesh size, and 210d/9-12 no thickness for wide-meshed net which have 250-280 mm mesh size. Total lengths of the encircling nets are varied between 265 and 660 m. Hanging ratios (E) are between 0,5 and 0,67. Each layer of the nets are 60-120 mesh deep for finemeshed net and 5,5-13,5 mesh deep for wide-meshed net. Encicling nets can be formed 3-8 in layers.