What does this indicator measure?
This indicator measures the fraction of caught fish that are discarded by fishing vessels for each species.
Access the West Coast Shorebased IFQ Program Interim Results and the Northeast Multispecies Sector Program Interim Results for Ecological Indicators
Why is this indicator important?
Some catch share programs limit the amount of fish that can be brought back to shore, while others may consider discards as part of the total catch share. Either case may create incentives to discard fish that exceed the catch share, or to retain only those fish of a given species that are most valuable (“high-grading”). However, fishers can lease catch shares or join risk pools to cover their overages, which may reduce discarding. Many discarded fish die as a result of the physiological stress of being caught or from handling damage during the fishing process, so that discards are considered both economically wasteful and ecologically harmful.
How is this indicator measured?
Federal observers on board fishing vessels record the species and amount of fish caught and discarded. A simple calculation of discarded weight divided by total catch gives the annual discard fraction, or rate, in each year. This fraction can be compared from before and after the catch share programs were implemented.
What are the strengths and limitations of this indicator?
This indicator is a good measure of the amount of discarding. However, it should be noted that some management regulations are designed to ensure that total mortality (retained catch plus discard deaths) is sustainable. In other words, if discards are high, regulations could require lower amounts of landings. Where observer coverage is limited, the estimated discard fractions will be more uncertain, and the data may be biased if fishers change their fishing behavior when an observer is on board.