Population dynamics in marine conservation

This chapter traces the evolution of models for fishery management, focusing on the problem of maintaining both replacement and a desirable level of yield. Early models from the 1950s led to management for maximum sustainable yield (MSY). Later, recruitment and egg production data from populations at low abundance were used to set critical replacement thresholds (CRT) using age-structured models. Modern fisheries are managed by control rules to avoid both overfishing (replacement too low) and being overfished (abundance too low). With the advent of spatial management through marine protected areas (MPA), strategic models showed that MPAs and conventional management essentially had the same effects on fishery yield. More realistic, spatially explicit, tactical models include more detail but produce results that support the conclusions of the strategic models. Finally, the growing science of adaptive management of MPAs has been based on the understanding of transient population dynamics from Chapter 4.