A comparative study of three river systems leading into Nootka Sound, British Columbia: implications for winter salmon populations

Abstract

[author abstract] Data collection consisted of plankton tows, and temperature, pH, and salinity readings taken at multiple stations within the Tahsis, Zeballos, and Gold Rivers located in Vancouver Island, British Columbia in December, 2015. These samples and data from previous research were used to analyze which river system could best support juvenile, winter salmon. Salinity and pH do not appear to be driving factors in these river systems in respect to salmon prey abundance, while temperature could affect salmon survival. All three rivers were composed of like species with the Tahsis and Zeballos rivers having the most similar compositions of organisms. Salmon prey of interest included species of Plecoptera, Cladocera, Nauplii, and copepods from the orders Calanoida and Cyclopoida. Species richness and diversity varied across all three areas of study. All three rivers could be suitable for winter salmon, but the Tahsis River could best support winter salmon populations if temperature and prey composition are the most influential factors on salmon growth and survival.