Abstract. The purpose of the study was to obtain preliminary data on the effect of dietary protein on the growth of the thick-lipped grey mullet (Chelon labrosus) juveniles reared in net sea-cages. The juveniles (6.2 ± 0.61 g) were obtained from the wild and were stocked into net sea-cages at a stocking rate of 100 juveniles per cubic meter and fed with experimental diets including 25, 30, or 35% crude protein for 87 days. The highest mean weight and specific growth rate (SGR) were 39.5 g and 2.13% day -1 , respectively, at protein levels of 30%. The diet also resulted in the most efficient feed conversion ratio of 1.61.

The effect of various water temperatures on growth and survival rate of juvenile sea cucumbers (Holothuria tubulosa) had been investigated in this research. Average weight of 20.48±2.33 g of juvenile sea cucumbers were collected from the coastal zones of Aegean Sea by scuba diving. After the adaptation period, juveniles were placed into glass aquaria which have 4 different sea water temperatures and researched for 45 days under laboratory conditions. Sea water temperatures of trial groups were selected among the minimum (winter) and maximum (summer) temperatures recorded at the natural habitat of H. tubulosa juveniles. Thus, 4 temperature group were selected as 15, 20, 25 ve 30°C. The sea cucumber juveniles were fed on dried and powdered brown algae as references in the literature. The best specific growth rate (SGR) was recorded as 0.288±0.02 % day -1 in 25°C group. The lowest SGR was recorded as 0.085±0.005 % day -1 in 30°C trial group while the negative specific growth rate (-0.03±0.02 % day -1 ) was recorded in 15°C trial group. The aestivation observed in 30°C and hibernation in 15°C group would be a reason for such lower specific growth rates. The survival rate for all groups were 100% and the best growth performance was recorded in 25°C among others (P<0.05).Keywords: Sea cucumber, Holothuria tubulosa, aquaculture, temperature, growth. Farklı Sıcaklıklarda Deniz Hıyarı (Holothuria tubulosa, Gmelin, 1788) Genç Bireylerinin Büyüme ve Yaşama Oranı ÖzetBu çalışmada, farklı su sıcaklıklarının deniz hıyarı (Holothuria tubulosa ) genç bireylerinin büyüme ve yaşama oranları üzerine etkileri araştırılmıştır. Ortalama 20,48±2,33 g ağırlıktaki genç H. tubulosa bireyleri Ege Denizi kıyılarından serbest dalış yöntemiyle elle toplanmıştır. Toplanan bireyler adapte edildikten sonra, laboratuar ortamında 45 gün boyuncadeniz suyu bulunan cam akvaryumlarda denemeye alınmıştır. Deniz hıyarlarının dağılım gösterdiği bölgedeki yaz ve kış deniz sıcaklıkları (en düşük ve en yüksek) sınır olmak üzere 4 farklı deniz suyu sıcaklığında (15, 20, 25 ve 30°C) deneme grupları oluşturulmuştur. Deneme süresince deniz hıyarları kurutulmuş kahverengi alg ile beslenmişlerdir. Deneme süresi sonunda en yüksek spesifik büyüme oranı (SBO) 0,288±0,02 % gün -1 olarak 25°C de kaydedilmiştir. En düşük spesifik büyüme oranı 0,085±0,005 % gün -1 değeri ile 30°C'de görülürken, 15°C'de negatif yönlü (-0,03±0,02 % gün -1 ) SBO kaydedilmiştir. Büyüme oranlarındaki düşük değerlerin 30°C'de gözlenen estivasyon (uyku) ve 15°C gözlenen hibernasyon davranışına bağlı olduğu düşünülmektedir. Tüm deneme gruplarında yaşama oranı %100 olup en iyi gelişim 25°C 'de tespit edilmiştir (P<0,05).

In this study, the effects of water temperature on growth, survival rate, gonad development and sex ratios of Mozambique Tilapia (Oreochromis mossambicus) were studied by applying different temperature applications (28, 30, 32, 34 and 36 o C) for a single period of 40 days. At the end of the study, in the control group (28 o C), the males proportion was 47.62%. In fishes reared at 30 o C, average male ratio was found as 73.68%. The highest male proportion was obtained in the 36 o C temperature group (86.67%). Growth performances, feed utilization and gonad development were found to increase with elevating temperatures up to 34 o C unlike the survival rate which has been found to fall with higher temperatures. In this study, sex differentiation rates differed significantly between all groups (p<0.05). However, the highest male rate obtained in group A and D. As hypothesized, results suggest that fish performed better at 30-32°C than 28°C or 34-36°C water temperature and the optimum temperature for a better expression of growth parameters in Mozambique Tilapia could be 30 o C.

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