Critical thermal maximum of seven estuarine fishes

Abstract

Critical thermal maximum (CTM) and loss of righting response (LRR) were determined in seven estuarine fishes. The critical thermal maxima (CTM) ranged from 39.5°C to 44.5°C for fishes acclimated to 28°C. Lates calcarifer and Liza dussumeri had the highest CTM (44.5°C) and Siganus javus had the lowest CTM (39.5°C). The rate of change of CTM due to thermal acclimation was determined for Etroplus suratensis and Therapon jarbua. The CTM for E.suratensis increased from 39.75°C to 43.5°C on a 15°C increase in acclimation temperature and the CTM of T. jarbua shifted from 40.75°C to 43.15°C on a 15°C increase in acclimation. The acclimation response ratio (ARR) as a result of increasing the acclimation temperature was about 0.25 in E. suratensis and 0.2 in T. jarbua.