Recolonization of Experimentally Defaunated Tidepools by Northeast Pacific Intertidal Fishes

Abstract

Site fidelity and maintenance of home ranges are common in fishes (e.g., Stephens et al., 1970; Robertson and Sheldon, 1979; Hixon, 1981), especially for intertidal species for which the ability to navigate to a safe region of an environment that periodically drains of water may be adaptive (e.g., Gibson 1967, 1969, 1982). For intertidal fishes in the northeast Pacific region, homing capabilities have been described in the cottids Clinocottus analis (Richkus, 1978), C. globiceps (Green, 1973), Oligocottus maculosus (Green, 1971; Khoo, 1974; Craik, 1981), and Oligocottus snyderi (Williams, 1957; Halverson, 1982; Yoshiyama et al., 1992). The adaptive value of homing in intertidal fishes has not been fully explained, but it is of sufficient ecological benefit to have arisen independently in fishes of different lineages (e.g., Cottidae, Blenniidae) and in different geographical regions (western North American coast, Britain; Yoshiyama et al., 1992; Gibson, 1967). Aside from its possible benefits in the search for food and escape from desiccation or predators, the ability to home may be used by fishes requiring refuge from hydrodynamic stresses imposed by waves (Chotkowski, 1994). Despite the apparent importance of site fidelity and homing ability in intertidal fishes, even species that show such localization behaviors have substantial segments of their populations that are vagile and presumably able to colonize new areas (e.g., Richkus, 1978; Craik, 1981). The rates at which juvenile and adult fishes colonize new habitat are of interest be-