Passive reclamation of soft-sediment ecosystems on the North Coast of British Columbia, Canada

Abstract

Estuarine ecosystems are degraded through anthropogenic development, leading to reduced habitat suitability for biological communities. The Skeena River estuary (British Columbia, Canada) is undergoing passive reclamation from historical salmon canneries and pulp mills, while localized disturbances continue at present. To reveal both current impacts and the trajectory of passive reclamation from historical activities, the intertidal mudflat surrounding the longest operating salmon cannery, Cassiar Cannery, within the Skeena estuary was surveyed. Nutrient availability (chlorophyll a concentration/organic matter content), sediment variables (particle size, water content, penetrability, woody debris/macroalgae cover, apparent redox potential discontinuity depth), and infaunal community composition varied spatiotemporally, and suggest that an old dock may be influencing the infaunal community given the abundance of disturbance indicating taxa below the dock. However, with populations of amphipods, mobile polychaetes, and a complex community structure, the mudflat as a whole appears to be relatively healthy. Therefore, cessation of historic activities has allowed for passive reclamation to a reasonably unstressed state, though a threshold of recovery may exist for intertidal mudflats beyond which passive reclamation will not be effective.