Thermal effects of power plant entrainment on survival of larval fishes: a laboratory assessment

Blueback herring (Alosa aestivalis), American shad (Alosa sapidissima), and striped bass (Morone saxatilis) larvae from the Chesapeake Bay region were subjected in the laboratory to time-excess temperature histories typical of those experienced by organisms entrained by power plants with a variety of design and operating criteria. The maximum excess temperature ranged from 7° to 20°C above the base temperature (the average surface water temperature on the spawning grounds); the time of exposure to a maximum excess temperature from 4 to 60 minutes; and the period of cooling to the final temperature from 60 to 300 minutes. An excess temperature of 20°C resulted in virtually total mortality of larvae of all three species. Striped bass larvae were the most tolerant of the, three species and could withstand excess temperatures of up to 10°C with no significant increase in mortality. The response patterns of the other two species were more complicated.