Growth and Production of Eogammarus confervicolus (Amphipoda: Anisogammaridae) at a Log Storage Site and in Areas of Undisturbed Habitat within the Squamish Estuary, British Columbia

Abstract

Growth and production of Eogammarus confervicolus was investigated in three contrasting habitats within the Squamish estuary: a log debris area, an embankment along the perimeter of a Carex lyngbyei marsh, and a Fucus distichus community. Eogammarus confervicolus annual production was highest in the "bank" habitat (21.38–21.65 g∙m−2∙yr−1) followed by Fucus (11.31–12.99 g∙m−2∙yr−1) and then wood debris (6.12–6.75 g∙m−2∙yr−1). P: B ratios were similar for the bivoltine wood debris and bank animals (4.67–5.15 and 5.94–6.01, respectively) but lower for the univoltine Fucus population (3.28–3.76). Growth rates were judged to be higher in bank and Fucus than in wood debris. Mortality rates were highest in wood debris. The food available for estuarine amphipods in wood debris habitats is thought to be inferior to that produced in marsh and algal communities. Despite the fact that E. confervicolus production in wood debris was much lower than in undisturbed locations, the possibility remains that such areas are still adequate food gathering areas for juvenile salmonids, if water quality conditions permit fish access to the log storage site.