Productivity growth, catchability, stock assessments, and optimum renewable resource use

Productivity growth substantially impacts rent-maximizing resource stocks, and can lead to an economic optimum that has overfished stocks: BMEY<BMSY. Bioeconomic models can give biased results and policy advice when not accounting for time-varying catchability-notably due to productivity growth-and density-dependent catchability, and not distinguishing between fishery-dependent and fishery-independent data and implications for catchability, modeling, and applicability of results. Productivity growth, as a component of time-varying catchability, also impacts stock assessments. CPUE standardization and productivity measurement both face an identification issue in disentangling changes in resource stocks from changes in productivity as well as endogenous regressors for which there are potential identification strategies. An empirical example illustrates BMEY<BMSY.