A mechanistic stage-structured model for estimating maturation, mortality, and recruitment parameters of three economically significant fish species in Canadian waters

This study designs and analyzes a discrete-time, stage-structured model to estimate key life-history parameters (recruitment, maturation, and mortality) for three economically significant fish species in Canadian waters: Chinook Salmon (Oncorhynchus tshawytscha), Capelin (Mallotus villosus), and Cod (Gadus morhua). The analysis encompasses model wellposedness, the net reproductive number (R0), and the global stability of equilibria. Sensitivity analysis using Partial Rank Correlation Coefficients (PRCC) was performed to assess the influence of key parameters on R0 and long-term fish population abundance. Our findings reveal that recruitment and adult survival are the primary drivers of long-term population sustainability across all three species. While maturation transitions contribute positively to population growth, their influence is secondary compared to recruitment and survival. These results highlight the importance of effective management strategies that prioritize improving recruitment and adult survival while also supporting successful transitions between life stages to maintain stable fish populations and ensure the ecological and economic sustainability of fisheries.