Spatio-Temporal Interactions Between Fish Spawning Aggregations, Fisheries, and Climate Change

Fish spawning aggregations (FSAs) are loosely defined as temporary, predictable, and repeatable gatherings of large numbers of conspecific fish that form for the purpose of reproduction. These characteristics make FSAs both highly valuable to fisheries and highly susceptible to overfishing. FSAs vary considerably with respect to their spatial and temporal dynamics, including the timing and duration of aggregations, the abundance and distribution of fish within aggregations, and the scale of migrations to reach aggregations. Fishing activities are also highly variable with respect to the spatial and temporal distribution of effort, and the impacts of fishing on FSAs (e.g. reductions in reproductive output, population declines) are dictated by the interactions between fishing and spawning. Stock assessments of aggregating species that rely on estimates of reproductive potential are highly sensitive to age or size-dependent patterns in spawning frequency. Therefore, age or density-related variations in spawning behavior may significantly influence the estimated resilience of a species to fishing pressure and the rate of recovery following protection. Given the influence of water temperature on the timing of reproduction in marine fishes, global warming is likely to induce changes in the timing, duration, and locations of FSAs that may also alter their interactions with fisheries.