NOAA gets to the bottom of the Bering

Published on
October 7, 2014

Using new technology to map the ocean floor in the Bering Sea, U.S. National Oceanic and Atmospheric Administration (NOAA) scientists hope to have better methods to determine the effects of trawl nets on the ocean floor.

The North Pacific Fishery Management Council (NPFMC) will use the resulting data to determine whether it should further restrict pollock fishing in and around parts of the Bering Sea canyons to protect sensitive coral habitats. Fishermen landed 1.3 million metric tons of pollock in 2012 — the largest catch in the U.S. As such, the Council keeps close tabs on the Pollock populations, and catch limits are set well below what the stock can support, according to NOAA.

Still, the NPFMC and NOAA want more scientific data — beyond trawl bycatch data and modeling — to determine the extent of coral populations in the Bering Sea. Plus, Greenpeace and other organizations have expressed concerns about the effects of trawl nets on the ocean floor.

“We presented the [coral reef mapping] model to the NPFMC in 2013 and, as with any model, there is uncertainty,“ Douglas Demaster, director of NOAA's Alaska Fisheries Science Center, told SeafoodSource. “As a follow-up, there was some interest in verifying the model.”

To that end, NOAA Fisheries scientists recently conducted the first of its kind, broad-area survey, looking for deep-water corals on the outer continental shelf and slope of the Bering Sea. At 250 randomly selected locations, they dropped a bug-eyed, two-lensed camera into the water and took pictures. They will use the resulting 25,000 images — along with 3D technology — to identify corals, estimate their abundance, measure the dimensions of corals and gauge their importance as structural habitat for fish and crabs.

“This will be an exciting new piece of information that we don’t typically get,” Chris Rooper, research fisheries biologist with the Alaska Fisheries Science Center, told SeafoodSource.

The Center plans to have the coral data thoroughly analyzed by June 2015, when it will present the new information to the NPFMC. “The Council tends to use a fairly fine brush in terms of protected areas, and it needs a high resolution data set to do that,” Demaster said. “The new technique with cameras, plus bycatch data, is a good way to determine if the model [presented in 2013] was missing anything.”

Already, the photographic mapping has resulted in preliminary findings similar to the model. “The Bering Sea slope has pretty low concentrations of coral throughout compared to some places, like the Aleutian Islands,” Rooper said.

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