This study was performed to evaluate the effective concentration of the anaesthetic 2-phenoxyethanol (2-PE) on juvenile (1.3 ± 0.03 g) meagre (Argyrosomus regius, Asso, 1801) and establish the LC 50 (through a series of exposure concentrations) and LT 50 of 2-PE at 20 ± 0.5°C, salinity 38 g · L )1 , pH 8.2-8.4 and dissolved oxygen >7 mg · L )1 . The induction time decreased and the recovery time increased with increasing concentrations. Conflicting results were found only in recovery time and there were no significant differences among the recovery times from all concentrations. The most suitable concentration of 2-PE was 0.3 ml · L )1 for about or over 15 min exposure time. The LC 50 and LT 50 for the 3-60 min exposure periods were estimated for juvenile meagre. The toxic effect of 2-PE on survival rates of A. regius juveniles increased depending on the exposure period. In addition, 2-phenoxyethanol LT 50 (median survival time) values, slope function (S) and lower and upper 95% confidence limits were estimated.

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European catfish (Silurus glanis L.) is a fish that has a high economic value due to its rapid growth and delicious flesh. In this study, the growth performance of European catfish was investigated in freshwater and 5‰ salinity in recirculating system. The study was carried out using fish with an average weight of 507±13.02 g and an average total length of 42.85±0.45 cm in freshwater (Y1, Y2, Y3) and 5‰ salinity of ground water (T1, T2, T3) designed as three replications for three months. Fish were fed with 3% of the total weight two meals a day. The mean body weight gain, total lenght increase, amount and percentage of feed consumption, specific growth rate (SGR) and feed conversion rate (FCR) were higher in group Y (P<0.05). No statistical difference was observed between the survival rates of the groups (P>0.05). As a result, it is concluded that this species can be reared in both fresh water and 5‰ saline water.

SummaryThis study was conducted to examine the effects of feeding diets, different dose of vitamin E contains, on female and male Black Sea trout's (Salmo labrax) reproductive performance. Broodfish were fed with dry feed contained 100 (control), 250, 500, 1000 mg kg -1 vitamin E. Milt volume, spermatozoid number, fecundity and egg size were determined. Milt volume and sperm number were positively affected at a dose of 250 and 500 mg kg -1 vitamin E in the diet. A similar positive trend was also observed at the dose of 1000 mg kg -1 . Egg size is not affected by dietary vitamin E dose, but there are positive relationship between total fecundity and dietary vitamin E dose especially at the first stripping (P<0.05).Keywords: Milt, α-tocopherol, Broodstock, Fecundity, Vitamin E Vitamininin Karadeniz Alabalığı (Salmo labrax) Damızlık Stoklarında Üreme Performansına Etkisi ÖzetBu çalışma Karadeniz Alabalığı'nda (Salmo labrax) 6 hafta süreyle, yemlerine farklı dozlarda ilave edilen E vitamini ile beslemenin üremeye etkisini ortaya koymak amacıyla yapılmıştır. Anaç stoktaki balıklar 1 kg yemde 100 mg (kontrol grubu), 250 mg, 500 mg ve 1000 mg olacak şekilde E vitamini ilave edilen yemle beslenmişlerdir. Sperm hacmi, spermatazoa sayısı, fekondite ve yumurta çapı verileri incelenmiştir. Sperm hacmi ve spermatozoa sayısı 250 ve 500 mg E vitamin içeren yemlerle beslenen balıklarda pozitif yönde etkilenmiştir. Benzer ilişki 1000 mg kg -1 dozda da görülmüştür. Yumurta büyüklüğü yemdeki E vitamininden etkilenmezken, özellikle ilk sağımda total fekondite ve vitamin E miktarı arasında pozitif ilişki vardır (P<0.05).

Duo culture response of Siberian sturgeon (Acipenser baeri) and rainbow trout (Oncorhynchus mykiss) was evaluated in culture tank conditions. Triplicated culture groups were planned as: mono-culture sturgeon (M, n=10), duo-culture sturgeon (DM, n=10) and duo-culture trout (DA, n=10), and mono-culture trout (A, n=10). Examination of mono and duo culture of each species, showed neither sturgeon nor trout, was indicated any significance on specific growth rate (SGR) and condition factor (CF). As for final biomasses among groups, no significant differences were recorded (p<0.05).