Ecosystem Modeling
Ecosystem modeling will be used to determine which environmental conditions have the greatest effect on the survival of the five groundfish species that are the focus of this study (walleye pollock, Pacific cod, Pacific ocean perch, sablefish and arrowtooth flounder). A series of models will be used to examine the effects of oceanography, current patterns, nutrient availability, food availability, predator interactions, and various combinations of these factors on how these fish survive under different conditions. This information will help managers to predict fish survival and therefore predict more accurately the number of fish that should be available to support the ecosystem and to commercial fisheries in the future. Retrospective data will be used to develop the models and field data will provide information about current conditions and will be used to test the predictive power of the models.
Oceanographic models
Regional Oceanographic Modeling Systems (ROMS) will be used to model the oceanography that transport larval fish from areas offshore where they were spawned to nearshore nursery areas. Factors like water temperature, salinity, wind, and current patterns will determine if fish are transported to appropriate nursery areas and how they grow and survive.
Nutrient Phytoplankton Zooplankton (NPZ) models
Nutrient Phytoplankton Zooplankton (NPZ) models will examine the effects of varying the levels of nutrients, phytoplankton, and zooplankton in the water column, which will provide information on the productivity of the system, and the availability of prey, under different environmental conditions.
Individual Based Models (IBM)
Individual Based Models (IBM) will be developed for each of the five focal groundfish species and will provide information about the basic life history and behavior of these fish as they grow from eggs to larvae and juveniles and are transported from spawning to nursery areas. Information about the typical depth at which they spend time during a given life stage, and the time that elapses between stages is typical input into the model. The IBM, NPZ, and ROMS models are nested so that the oceanography determines the location of a given fish at a particular time, the NPZ model determines the productivity at that location, and the IBM determines if the habitat is suitable for the fish during that stage of its life cycle. The combination of these environmental conditions determines fish survival.
Multi-species models
Multi-species models will be used to examine the interactions of changes in the number of the primary species (with changes in the environment), and abundances of species in other parts of the ecosystem which may eat or be eaten by the main species (as well as how fishing may impact all of these species).
