Salmon escapement

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Salmon escapement is the number of salmon that are not caught and return to their freshwater rivers to spawn. Scientists estimate escapement each year using data from that run and statistical methods to help set fishing quotas for the next year or to judge the health of the stock.

Common ways to estimate escapement:
- Area-under-the-curve (the most common method)
- Change-in-ratio method
- Carcass-counting surveys
- Weir-count surveys

Biological Escapement Goals (BEGs): the target number of returning salmon that allows the most harvest while still leaving enough fish to spawn and replace future harvests. BEGs help managers decide how many fish to harvest and where they should spawn for that population.

Sustainable Escapement Goals (SEGs): the escapement level that is known to provide a sustainable yield over about 10 years, based on available data. SEGs are used when there isn’t enough catch data for a stock, such as some Alaska fisheries where fishing happens in non-terminal areas and the final spawning destination isn’t known.

Optimal Escapement Goals (OEGs): a plan that considers both biology and how quotas are allocated. OEGs may differ from BEGs or SEGs and are used when managers want to reallocate quotas. OEGs are shown as a range, with the lowest level kept above the sustainable escapement estimate to ensure long-term sustainability.