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Have discarding practices changed?

Indicator: Ratio of Discards to Landings

This indicator measures the fraction of caught fish that are discarded by fishing vessels, by species.


Discarding is widely acknowledged to be a wasteful practice. If catch shares end the race to fish, and if there are incentives to avoid discarded bycatch, then discard fractions may decrease as fishermen avoid areas with smaller fish sizes or less commercially attractive species. For all methods of estimating discard ratios, the discard rate in the first year of the catch share program was lower than in any year in the previous decade.

Baseline Years: Prior to Catch Share Program

Discard data are fully available for the 2002–2010 baseline period. The crude discard fraction (total discards divided by total catch) generally declined during those years from 45 percent to 18 percent, but that trend was driven by a few abundant species groups that composed the bulk of the catch. If we instead calculate the discard fraction for each stock and average across stocks for each year (looking only at species that comprise 95 percent of catches), the average discard fraction is higher and shows a weakly declining trend throughout the baseline period. The discard ratios among only those species that are assessed were generally constant throughout the baseline period.

Catch Share Program

We have only a single year of data for the catch share program, so we do not yet draw any conclusions about changes in discard ratios. However, we do note that all measures of discard ratios were lower in 2011, the first year of the catch share program, than they were from 2002 to 2010. The direction of that change is consistent with the predicted change following catch share implementation. However, additional years of data will be analyzed as they become available to ascertain whether this change is persistent and whether it can be attributed to the catch share program.


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Data Gaps and Limitations

Data for 2012 at the scale needed for this analysis were not available for this release of interim results. The results for 2012 will be included in a future update.

We have not yet examined discards of threatened, endangered, and protected species. Future analyses will treat bycatch and discards of species in these groups separately.

Information Sources

Data on discards and total landings were provided by the NOAA Northwest Fisheries Science Center.

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Ratio of Discards to Landings (pdf) – September 2013

Updated: September 26, 2013