Temperature Requirements for the Survival and Early Development of the Anadromous Alewife

Abstract

Abstract Studies were conducted to determine the effects of temperature on the hatching success of eggs of the alewife (Alosa pseudoharengus) and on the growth, survival, upper tolerance limit, and temperature preference of alewife larvae from the Hudson River. When eggs were incubated at seven constant temperatures ranging from 12.7 to 29.7°C, maximum hatching success occurred at 20.8°C. Hatching success fell significantly (P < 0.05) below the maximum when eggs were incubated at 26.7-26.8°C, and no hatch occurred at 29.7° C. The average time to median hatch varied inversely with temperature, ranging from 7.4 days at 12.7°C to 3 days at 23.8-23.9°C and 26.7-26.8°C. The upper tolerance limit of yolk-sac larvae acclimated to 14-15°C and exposed to elevated temperatures for 24 h was about 31°C. At seven constant temperatures ranging from 12.9 to 29.1°C, average daily rates of larval weight gain during the first 12 days after hatch increased with each higher temperature to a maximum of 83.8 µg/day (dry weight) at the highest rearing temperature (29.1°C). The maximum net biomass gain occurred at 26.4°C. The final preferendum of young alewives was estimated to be 26.3°C by monitoring their distribution in a thermal gradient during a 33-h period.