Bottom Fauna of Portions of the Cowichan River, B.C.

Abstract

The yields per sq. m. computed as (1) av. wet wt. and (2) no. of organisms were: pool—36.91 g., 745; riffles—14.60 g., 1061; creek—8.25 g., 536. Vegetation is the most productive type of habitat, followed by mud, rubble, gravel bottom. The river may be designated as a "Trichoptera stream". No close correlation was found between no. of organisms in bottom fauna and no. in trout stomachs, thus suggesting discrimination among trout for food organisms.