This report describes a daily simulation model for the Area 4 commercial gillnet fishery. The model evaluates the effects of various gillnet fishing patterns on the catch and escapement of sockeye, steelhead (including sub-stocks), early-run coho, chinook, and pink salmon migrating through four sub-areas of Area 4. The model is a useful tool for evaluating alternate management options for the Area 4 fishery. The model also provides managers with an objective and consistent framework for pre-season planning.