Maturation rates are stock and age specific for all stocks. Some stocks have variable maturation rates. Production functions for both hatchery and natural stocks are estimated from historical data. This type of analysis involves the reconstruction of an annual series of abundance estimates using catch and escapement data and making assumptions about natural and incidental mortalities. Model parameters can be obtained from the PSC Chinook Technical Committee, or advanced users can utilize there own parameters.
Harvest allows the operator to change parameters and view results interactively.
Parameter values can be changed by using the mouse or keyboard. A 25 year simulation with 30 stocks and 25 fisheries takes less than 10 seconds. Results can be presented in graphical form on the screen immediately after a simulation run, or can be downloaded to data files for archiving or further analysis. The period from 1979 to the present is used as the calibration period. The operator must make assumptions about the future values of key environmental parameters, such as brood year survival rates and maturation schedules.