Critical thermal maxima of three species of Hawaiian estuarine fish: a comparative study*

Crticial thermal maxima (CTM) of three species of Hawaiian estuarine fishes were determined in relation to acclimation temperature and time of day. The species studied were Mugil cephalus L., Chelon engeli (Bleeker) and Kuhlia sandvicensis (Steindachner). Critical thermal maxima of all three species were significantly affected by acclimation temperature and time. In relation to acclimation temperature, Mugil cephalus and Chelon engeli have similar critical thermal maxima with Kuhlia sandvicensis having a critical thermal maxima about 1° C below that of the other two species studied. Mugil cephalus and Chelon engeli showed an increasing critical thermal maxima toward midday which decreased therafter. Critical thermal maximum of Kuhlia sandvicensis increased throughout the day.