Effects Of Increased Temperature On Postlarval And Juvenile Estuarine Fish

We simulated thermal increases encountered by postlarval and juvenile estuarine fishes entrained in power plant cooling systems. Three methods were used to measure the effects of thermal shock on these fishes: (1) critical thermal maximum (CTM); (2) changes in routine oxygen consumption; and (3) survival after exposure to sudden increases in temperature for various periods of time. For menhaden, spot, and pinfish acclimated at 15° C, CTM values were 29.4, 31.0, and 31.0 respectively. Oxygen consumption of menhaden, spot, and pinfish, increased as we raised the temperature in 5° increments from the environmental temperature, indicating that additional energy expenditures are necessary to maintain the fish at the elevated temperatures. At temperatures of 15° C above the normal environmental temperature, all of the menhaden, spot, and pinfish died within 5 to 10 minutes. Young striped killifish acclimated at 22° C survived at 39° C for more than 30 minutes but all died at 40° C.

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51813