Spatial Scale and Fish Movement As Key Factors for Interaction Between Marine Mammals and Commercial Fisheries

The Alaska Fisheries Science Center’s Fisheries Interaction Team (FIT) was formed specifically to study the potential for adverse interactions between commercial fisheries and endangered Steller sea lions.  Over a decade of field research indicates that the relative spatial and temporal scales of fishing, sea lion foraging, and fish movement are critical in determining when an interaction may occur.  Details of field research that demonstrate this result will be presented, along with results of simulation modeling of differing levels of spatial overlap between fish concentrations, fisheries, and central-place predator foraging.  For static prey populations, localized depletions from fishing can affect predator foraging.  With mobile prey populations, however, there are many conditions where no interaction occurs.