Advanced Sampling and Analysis Methods for Ecosystem Monitoring

Acoustic-trawl surveys are used to annually survey Pacific sardine off the west coasts of the USA, and Vancouver Island, Canada. Described are the sampling and analysis methods used to estimate time series of potential oceanographic habitat; stock biomass, spatial and size distributions, growth, fishing and natural mortalities, and environment-driven recruitment success. These methods are now being applied to empirically assess multiple other species in the forage-fish assemblage in the California Current. Highlighted are the principal sources of measurement and sampling uncertainty. Briefly introduced are some new acoustic instruments and methods being developed to monitor more species and their habitats, and mitigate some potential sources of systematic and random error.