Environment and Distribution of Age 0 Fishes in River Canard, a Lowland Ontario River

Abstract

Age 0 fishes were collected to determine occurrence, relative abundance and species composition at three sites in River Canard, Ontario in spring-autumn, 1994-1995. This small lowland river (mean annual discharge, 3.2 m³ s^-1) has variable flow during fish spawning and early nursery periods, high suspended particulate load, and sparse rooted vegetation and other physical cover. Forty-two taxa (12 families; 24,544 specimens) collected with beach seines and a plankton net represented a wide range of reproductive strategies and a diverse taxocene. Gizzard Shad Dorosoma cepedianum (67% of total catch), Orangespotted Sunfish Lepomis humilis (8%), and Brook Silverside Labidesthes sicculus (6%) were the most abundant species. Environmental conditions were such that fish attained autumnal lengths comparable to species in various systems throughout the ecoregion.