As stocks rebuild or decline at different rates over time, relative harvest rates in fisheries with catch ceilings also change. Single stock models cannot simulate this type of interaction. Harvest enhances the features of the PSC Chinook Model by providing a graphical interface to view and change model parameters, flexible code that permits expansion of the model, vastly increased computational speed and data storage capacity, and a stochastic operational capability providing measures of variability and uncertainty in assessing the impacts of proposed harvest management actions. Theory CRiSP Harvest is an empirically based stochastic model simulating fish survival over a complete life-cycle. Harvest is an accounting device for tracking the fate of individual chinook salmon cohorts through time.
Population aging occurs at the start of each year.
The model is seeded with initial cohort sizes for all stocks. The maximum age for all stocks is fixed at five years. Brood year survival rates during simulation years can be deterministic or stochastic. Maturation rates are stock and age specific for all stocks. Some stocks have variable maturation rates.