Effects of the Brown Tide Alga on Growth, Feeding Physiology and Locomotory Behavior of Scallop Larvae (Argopecten irradians)

Abstract

Dense blooms of a picoplanktonic alga occurred during the summer months of 1985 in Narragansett Bay, Rhode Island (Sieburth et al., 1988) and in 1985 and 1986 in coastal embayments along the eastern and southern shores of Long Island, New York (Cosper et al., 1987). Commonly known as the brown tide, the blooms appeared to cause massive mortalities, tissue weight loss and recruitment failures of suspension feeding organisms including the blue mussel Mytilus edulis L. in Narragansett Bay (Tracey et al., 1988) and the bay scallop Argopecten irradians irradians Lamarck in many Long Island embayments (Bricelj et al., 1987a; Cosper et al., 1987). Mechanisms potentially responsible for the deleterious effects on suspension feeders included depression of feeding activity and assimilation efficiency due to the high particulate load (> 10⁶ cells ml⁻¹, Cosper et al. (1987) inefficient retention of the small brown tide cells, poor nutritional value and production of toxic intra- or extracellular compounds.