Case Studies in Fisheries Conservation and Management: Applied Critical Thinking and Problem Solving
Case 7: Evaluating the Population Status of Black Sea Bass: One Step at a Time
In fisheries science, we never have perfect knowledge of a population, ecosystem, or fishery. However, we may be asked to make decisions about how to manage a stock even when we are missing some important information.
In many marine fisheries, management is based on both the fish population abundance or biomass and the current level of fishing mortality. There are two terms that express a stock’s status with respect to these two areas: overfished and overfishing. If a stock is “overfished,” its biomass has been depleted below a sustainable level (i.e., the biomass that would produce Maximum Sustainable Yield). If a stock is “undergoing overfishing,” the fishing mortality is higher than what is sustainable. Every stock will be within one of the four areas in Figure 7.1. For example, a previously unharvested population (B/B MSY > 1) which just became commercially valuable and has high fishing levels (F/F MSY > 1) would be undergoing overfishing but not overfished.