Stock Assessment

Modern stock assessments integrate acoustic surveys (hydroacoustic estimation of biomass), trawl surveys (age and size structure sampling), commercial CPUE data (catch per unit effort as a relative abundance index), and biological parameters (growth rates, natural mortality, maturity schedules). Virtual Population Analysis (VPA) and Statistical Catch at Age (SCAA) models reconstruct historical population trajectories. Uncertainty quantification is essential — the difference between the 'true' and 'estimated' stock size can easily exceed 30-50%, leading fisheries scientists to recommend harvesting well below the point-estimate MSY. New tools including environmental DNA (eDNA) sampling and machine-learning analysis of acoustic data are expanding assessment capabilities.