The director of the California Department of Fish and Wildlife (CDFW) opens the commercial crab season in a given fishing zone when the following 3 criteria are met.

Safe Domoic Acid Levels

Domoic acid is a toxin found in crustaceans and other shellfish. The FDA sets strict tolerable intake levels for Domoic acid. The CDFW works with the California Department of Public Health (CDPH) to test Domoic acid levels in Dungeness crab. To conduct a test, the CDPH takes a sample of 5 crab in a given management area and measures Domoic acid in the crab viscera (body). If the Domoic acid levels are below the safe level of 30ppm, that management area passes. See Figure 1 below for the Domoic acid management areas.

Low Number of At-Risk Species

Protecting humpback whales and other at risk species is another consideration when deciding the season opener. The CDFW receives Risk Assessment and Mitigation Program (RAMP) assessments from the Dungeness Crab Fishing Gear Working Group. These assessments, usually conducted via flyover, inform the CDFW how many of these at-risk species remain in a given fishing zone. When the count is below a the threshold for a given fishing zone, that zone passes. See Figure 2 for risk assessment fishing zones.

High Meat Quality

This requirement ensures that the crabs have a sufficient amount of meat. Meat quality is only tested above the Sonoma/Mendocino County line, so San Francisco and San Mateo counties and below are excluded from this requirement. Meat quality is measured by weighing a live crab, cooking and picking its meat, and weighing the picked meat. The weight of the picked meat is then divided by the weight of the live crab for a meat recovery percentage. The meat recovery needs to exceed a certain amount for the affected counties to open.