Temperature and salinity tolerances of yellowfin sea bream, Acanthopagrus latus, at different salinity and temperature levels

Abstract

Yellowfin sea bream Acanthopagrus latus (Houttuyn) (0.98 +/- 0.27 g) were examined for temperature and salinity tolerances at nine different environmental regimes (0.3, 15 and 33 ppt combined with 10, 25 and 32 degreesC), in which the fish were subjected to gradual and sudden changes in temperature and salinity respectively. The 50% CTMax (critical thermal maximum) and the UILT (upper incipient lethal temperature) were in the range of 34.8-38.2 degreesC and 32.8-36.4 degreesC respectively. The 50% CTMin (critical thermal minimum) and the LILT (lower incipient lethal temperature) were in the ranges of 4.9-9.4 degreesC and 7.1-17.6 degreesC respectively. The 50% CSMax (critical salinity maximum) and the UILS (upper incipient lethal salinity) were in the ranges of 54-69parts per thousand and 9-44parts per thousand, respectively. The fish at lower temperature (10 degreesC) and salinity of 33parts per thousand tolerated temperature as low as 6 degreesC when the temperature was decreased gradually. The fish at 33 and 15parts per thousand and lower temperature (10 degreesC) tolerated salinity as high as 66-67parts per thousand, whereas those at freshwater salinity level (0.3parts per thousand) and 32 degreesC tolerated salinity to 50parts per thousand when salinity was increased gradually. The relationships among UILT, LILT, 50% CTMax, 50% CTMin, UILS, 50% CSMax, salinity and temperature are given.