SIZE-RELATED HABITAT USE BY LONGNOSE DACE (RHINICHTHYS CATARACTAE)

Habitat use of 783 juvenile and 857 adult longnose dace (Rhinichthys cataractae) was surveyed to determine if habitat use was size-related in this riffle-dwelling fish. Contingency table analyses indicate that adults and juveniles were segregated by mean water column velocity and substrate type. Adults used areas with faster currents and boulders in a higher proportion than juveniles. However, analyses of habitat availability indicate that both adults and juveniles used areas with faster currents and boulders in a higher proportion than they occurred in the riffle at large. Both groups selected similar habitats but the adults were more selective than the juveniles, resulting in habitat segregation.