Did fishing impacts on seafloor habitats change?

Indicator: Seafloor Habitat Impacts

Short Answer: Yes. Impacts of fishing activity on seafloor habitats decreased under the catch share program.

Key Findings

  • Fishing effort and contact of fishing gear with seafloor habitats decreased after implementation of the catch share program.
  • During the baseline period, changes in regulations resulted in increased overlap between fishing activity and areas of living habitat on the seafloor.
  • The impact of fishing activity on sea pens and sponges decreased between the baseline and catch share program periods.

Interactive Chart Story


This indicator is based on data on geographic locations of fishing activity, amount of fishing effort, and distribution of living seafloor habitats, such as sea pens, coral, and sponges, in trawlable areas.


Catch share programs are expected to change the overall amount of fishing and the spatial location of fishing, in turn altering the impact of fishing on sensitive seafloor habitats formed by hard corals, sea pens, and sponges. This analysis examined whether such changes occurred after the West Coast Shorebased Individual Fishing Quota (IFQ) Program was implemented in 2011.

We only analyzed data for habitats in areas likely to be trawled—mainly soft-bottomed areas of the seafloor—and therefore this analysis does not address other habitat types, such as rocky reefs and canyons, that form essential habitat for rockfish and other marine life.

Baseline: Before Catch Share Program

The baseline period was marked by extreme shifts in locations of trawling as a result of newly implemented spatial management measures, which were not associated with the catch share program. Most notably, several policies adopted in 2006 closed many canyons, banks, and rocky reef habitats to trawling (History of the Fishery). Those regulations caused fishing activity to shift into areas further offshore from Oregon and Washington, where living habitats formed by corals, sponges, and sea pens were more common. Because of the greater overlap between fishing activity and living habitats, the exposure of sea pens and sponges to contact with trawl gear increased by 8 percent and 30 percent, respectively, in 2006 to 2010, before the catch share program began.

During Catch Share Program

The number of hours that fishing vessels spent trawling began to decrease in 2010 just prior to the catch share program and then declined further and remained low through the program’s first four years. All years from 2011 to 2014 had lower numbers of hauls and total hours of trawling compared to all years of the baseline period. The fleet set an average of 9,000 tows per year under the catch share program, compared to an average of 16,000 tows per year before catch shares, including a peak of 18,000 tows in 2009. Although overlap of fishing effort and living habitats remained relatively unchanged under catch shares, the reduction in fishing effort resulted in less exposure of living habitat to fishing gear. Exposure to fishing gear dropped by 43 percent for sea pens and 48 percent for sponges compared to the 2006-2010 averages. Taking into account the geographic shifts in fishing activity that occurred after 2006 during the baseline period, we estimate that the exposure of sea pens and sponges declined by 4 percent and 13 percent, respectively, under the catch share program compared to the 2002–2005 averages.

Information Sources

For this analysis, we used data from NOAA trawl surveys, observer data, and logbook data. For full details of the analysis, see the following reference:

Barnett LAK, Hennessey SM, Essington TE, Shelton AO, Feist BE, Branch TA, McClure MM. 2017. Getting to the bottom of fishery interactions with living habitats: spatiotemporal trends in disturbance of corals and sponges on the US west coast. Marine Ecology Progress Series 574: 29-47.

Updated: August 2018

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