Invertebrate Predators and their Role in Structuring Coastal and Estuarine Populations of Filter Feeding Bivalves

Abstract

Predators can often play an important role in regulating the distribution and population dynamics of their natural prey. The influence of any specific predator is likely to be most pronounced amongst specialist predators which feed on only a restricted number of prey species, and perhaps least pronounced amongst generalist predators in which the diet includes a much broader spectrum of alternative prey types. Even so, generalist predators can have a significant influence on their prey, especially when the predator occurs in abundance and/or a particular prey species is a preferred component of the diet. Populations of many marine bivalves, however, which are typically either sessile or extremely slow moving, are controlled not by any specific predator but by suites or guilds of predators, often operating at different seasons and/or amongst different size classes of their prey (Kitching and Ebling 1967; Suchanek 1978; Peterson 1979; Menge 1983; Sanchez-Salazar et al 1987a,b; Griffiths 1990).