Relationships between habitat characteristics and population abundance for brown trout, 'Salmo trutta L.', and blackfish, 'Gadopsis marmoratus Rich.', in Tasmanian streams

Habitat relationships are described for Salmo trutta L, and Gadopsis marmoratus Rich, in Tasmanian streams. Multiple linear regression models were developed relating population abundance with habitat attributes for G, marrnoratus but models describing a significant proportion of the variation in abundance of S. trutta could only be developed for streams of low hydrological variability. The derived model for S. trutta abundance (kg ha-') was tested against data from sites affected by a variety of impacts. Interrelationships between habitat attributes are described in relation to hydrological variability and bank erosion. Problems associated with the development of models relating habitat attributes and fish abundance are discussed in the light of the effects of hydrological variability.