Determination of critical minima and maxima of nile tilapia (O. niloticus) and hybrid tilapia (O.niloticus ? × O.aureus?) in different temperature levels

In this study we aimed to obtain to have the critical thermal valuation, under three different temperature combination; study reaction ratios and to find out thermal polygon areas for the origin of East African species of tilapia called tilopia of Nile (Oreocchromis niloticus ) and blue tilapias (Oreocchromis aerus ) hybirdization of hybird juveniles.The findings of the study has showed us fish studied in temperatured water has been significantly effected for the valuation of CTM and CTMax (p<0.001) and also showed us species has no significant effect relatively for both parameters. The temperature has been used 0.3°C and the results for the hybirds CTM ratios between 9.12 and 11.11 also CTMax ratios are between 39.77 and 42.50 . Tolerance of thermal plygon fiigures are for the hybirds between 246.181 and for the niloticus are 249.117°C2. Also study reaction ratios are shows us ; between 24-28 °C for the O.niloticus 0.30-0.26 ; also for the hybirds 0.33-0.42 .In three different temperature of water ( 24, 28, 32 °C ) the result of study reaction ratio for the O.niloticus between 0.24-0.34 and for the hybirds between 0.31-0.36 . This study shows that the variety of origin East African tilapias; under low temperatures is more sensetive but under high temperatures is more resistant . The tolerance zone under low temperature of the juveniles for niloticus is between 9.12 and 11.11 and for the hybirds between 9.60 and 11.94 . Tolerance zone under high temperature is between 39.77 and 42.66. When considering all these datas juveniles of tilapias ; in the deep pools which under high variabilty of the water temperature shows us juveniles will have serious problems but with the low variabilty of water temperatures and warm water possibilty reduce the amount of the problems of the juveniles; specially in summer times and temperature around 35-40°C on high temperatures of water projected as less problem when its compared to low tempearture of water.Keywords: Hybrid Tilapia, Critical thermal temperature, Acclimation response ratio, Thermal tolerans polygon, Aquaculture