Density and production of clinocottus globiceps and oligocottus maculosus (cottidae) in tidepools at helby island, british columbia

Abstract

Density and production of 2 dominant tidepool resident species, Clinocottus globiceps and Oligocottus maculosus, were estimated over a 2 yr period at Helby Island, British Columbia, Canada. Mean densities of O. maculosus fluctuated considerably with 2.5 and 13.7 fish m-2 of tidepool areas reported for the first and second year respectively. Density estimates for C. globiceps were 1.9 and 2.5 fish m-2 during the same period. Production was estimated by instantaneous growth rate method. Annual production estimates for O. maculosus were 1.8 g m-2 yr-1 in the first year and 11.0 g m-2 yr-1 in the second year, and corresponding values for C. globiceps were 8.1 and 7.0 g m-2 yr-1 respectively. Production reflected the distribution pattern of the 2 species, i.e. higher production was observed at the upper intertidal pools for O. maculosus and at the lower pools for C. globiceps. The relationships between physical characteristics of tidepools and production of the 2 species are given. None of the physical variables examined was a significant predictor of production.