The strongest measures protect ecologically important, sensitive, and rare habitats that are designated as Habitat Areas of Particular Concern. Seamounts and areas of undisturbed corals receive special attention and in some cases are off limits to all bottom-fishing gear. Large tracts of more common seabed ecosystems are protected by different rules that limit the use and types of bottom contact gears to minimize fishing impacts.
Protected waters in the North Pacific span hundreds of thousands of square miles. The largest protected area, in the Aleutian Islands, is larger than any state in the continental US.
New research has produced the most accurate estimates to date for the “footprint” of trawling in the oceans. In Alaska, area trawled now appears to be smaller than previously thought. Preliminary findings: just 5.8% of the Eastern Bering Sea is trawled. Researchers in the international Trawling Best Practices study increased resolution by using smaller spatial grids.
Bob McConnaughey, NOAA AFSC, pers. comm. in 4.28.2016 email to Brad Warren
Bottom trawling has changed in the North Pacific. Today’s trawl sweeps (right)—long cables that herd nearby fish toward the net mouth— are elevated above the seafloor by rollers. Footropes at the bottom of the trawl mouth ride above the seabed on buoyant rubber wheels (left) to protect benthic organisms.
To avoid harming habitats and creatures on the seafloor, trawlers with bottom-tending gear in the North Pacific have switched from heavy, conventional footropes and sweeps to lighter footropes and elevated sweeps. Rollers are widely spread on sweeps and footropes to limit their contact with the seafloor. Vessels have substituted rubber gear and rollers for the steel gear historically used in the fisheries. The rubber rollers and the rubber gear that are commonly used today have 20 percent of their dry weight when submerged in water, minimizing the effect on the seafloor. The Council authorized experimental fisheries to develop this gear, which reduces bottom contact by 80% to 90%. Cooperative research by NOAA scientists and fishermen demonstrated that elevating footropes in this way significantly reduced harm to seafloor organisms—reducing mortality in snow and Tanner crab encountering the gear. The flatfish trawl fleet widely adopted such modified gear to reduce effects on the seafloor even before regulations mandated its use for all flatfish fishing in the Bering Sea and Central Gulf of Alaska.
For video on how this gear reduces seabed contact, see low impact trawl gear tab.
Modified trawl gear, developed by scientists and fishermen, reduces contact with the seafloor by up to 90% compared to conventional gear. This has reduced impacts on crabs, sea stars, tunicates, and sponges.
The North Pacific Council turned to NOAA scientists to conduct a camera drop survey of the Bering Sea slope and canyons. The study sought to validate NOAA's coral prediction model for the area, collect information on the density and size of corals, collect data on sponges and other invertebrates known to provide habitat structure, and estimate what portion of the area showed evidence of fishing effects. Results showed that "densities of corals were low" and noted there were "no unique faunal features that distinguished Pribilof or Zemchung Canyons from the surrounding slope areas." The predominant seafloor type observed in the survey was mud and sand substrate. Corals were found in less than 3% of the survey tracks and most were less than 10 centimeters in height. Evidence of fishing on the substrate and biological features in the canyons and slope was also rare. Based on these findings, the Council determined that deep sea corals in the canyons show "low vulnerability" to fishing but asked NOAA to continue monitoring for changes in coral distribution and fishing effort.