Virginia Institute of Marine Science
To estimate the effects of entrainment of Mercenaria mercenaria embryos and larvae in the cooling water systems of steam-electric power plants, we used a thermal gradient apparatus. Cleavage stages, trochophore larvae and straight-hinge veliger larvae were subjected to 11 different temperatures for 8 different time periods. There was a direct relationship of mortality with temperature increase and, at higher temperatures , with increase in time exposure. As the clams aged, temperature tolerance increased, with cleavage stages most sensitive to higher temperature and straight-hinge larvae least sensitive. Multiple regression analyses of percentage mortality on temperature and time produced estimating equations that allow prediction of percentage 1nortality under different conditions of temperature and time exposure. Entrainment of M. mercenaria embryos and larvae in cooling systems of power plants should be as short as possible if mortality is to be held to a minimum.
Kennedy, VS; Roosenburg, WH; Castagna, M; and Mihursky, JA, Mercenaria mercenaria (Mollusca: Bivalvia): temperature-time relationships for survival of embryos and larvae (1974). Fisheries Bulletin, 72(4), 1160-1166.