SEAFOODNEWS.COM by Peggy Parker — Oct 1, 2014 — ANCHORAGE, Alaska — Extensive scientific research on Bering Sea corals by NOAA has shown that Greenpeace’s advocacy for special coral protections are not supported by evidence, and that there is no ‘crisis’ regarding coral protection in the Bering Sea Canyons.
Instead, an extensive $2.5 million study has produced over 225,000 digital images of Bering Sea canyon and slope floor, and this is being used by NOAA to refine an understanding of where coral concentrations are, and where they may need special protections.
Seafood buyers who have written the N. Pacific Management council about Corals should be proud of the process that has unfolded.
Images from the first ever, large-scale survey targeting corals on the Bering Sea Slope are in. The more than 225,000 digital images are being examined by coral experts and fisheries biologists from the Alaska Fisheries Science Center to ground truth a predictive model for the presence or absence of corals in the canyons of the Bering Sea.
Preliminary assessments will be given to the North Pacific Fishery Management Council (NPFMC) in early October. Over the next several months, the images will be scrutinized for coral location, size, density, fish affiliation and fishery impacts to the corals and presented in more depth in spring of 2015.
A survey this large and systematic had never been attempted before. The results are expected to validate and refine AFSC’s predictive model on coral, making a more accurate and fine-tuned assessment of the underwater colonies possible. If areas of high-density corals are found, protection measures can be more focused and precise.
Two of the Bering Sea’s five canyons, the centrally located Pribilof and Zhemchug, which may be the largest undersea canyon in the world, have attracted media attention lately because of a Greenpeace campaign aimed at closing the canyons to all commercial fishing.
Not a lot of commercial fishing takes place in the canyons. Less than three percent of all the pollock landed in the Bering Sea comes from these areas. These very wide, shallow-sloped, sandy-bottomed canyons are the source of less than six percent of all the fish caught in the Bering Sea.
Regardless, in 2007, Greenpeace sent a submersible down into the Pribilof Canyon. Along with their own scientists and observers, they invited NOAA coral expert Bob Stone. A few years earlier, Stone authored the most comprehensive study of coral gardens in the Aleutian Island area.
Stone’s work, along with the extensive analysis, research, and public comment that makes up the process through which Council management decisions are reached resulted in a 2006 decision to prohibit commercial fishing in some of the most magnificent coral areas of the Aleutian Islands.
“The conditions in the Aleutian Islands that make the coral gardens possible,” says Stone, “are really quite rare in the world. Maybe unique.”
When the Greenpeace invitation to study the canyons came along, Stone was ready.
“I’d read all the trawl surveys, bycatch data, all the reports on the canyons and the slope,” Stone says. “I wanted to see the area, and I wanted to make sure the study was done scientifically.
“The study results were pretty close to what I’d expected, which was far more areas where there was no coral than there were areas that had some. I explained it to Greenpeace carefully, but they didn’t want to hear it.
“In my opinion,” Stone says, “Greenpeace just went too far in how they characterized the results.”
Canyons
When Greenpeace set up a second cruise in 2012, they invited Stone again. This time Stone declined. “I was pretty busy and really had no extra time. When I have extra time, I want to be studying corals on the ocean floor,” Stone says.
John Olson, fisheries analyst for NMFS said the Greenpeace cruises were “very expensive and couldn’t cover much ground.” But he acknowledges that Greenpeace and other environmental groups who participated in the Council process had some effect.
Management decisions made at the regional fisheries councils must be grounded in “best possible science.” The data Greenpeace gave to the Council helped, but it was not extensive or rigorous enough to merit management changes.
More studies were done, including a 2012 NOAA Fisheries project that looked at corals, sponges, crabs, and fishes in the Bering Sea slope. Researchers found that species composition varied mainly with depth and latitude. But at a given depth and latitude, species composition was similar both inside and outside the canyons.
Near the western slope of the Pribilof Canyon, for instance, coral densities spilled over to the slope floor. There, coral densities were about one-fourth those found in the Aleutian Islands area generally, and about one-twentieth those found in the Aleutian Island coral gardens.
Two Council motions in June 2013 authorized AFSC to expand their initial analysis of corals, called for a discussion paper on management measures to conserve coral areas, asked for further research support from the Deep Sea Coral Research and Technology Program, and began a Bering Sea Fishery Ecosystem Plan for both the Pribilof and Zhemchug Canyons.
In April of this year, the Council adopted a purpose and needs statement justifying potential amendments to the groundfish and crab fisheries management plans to protect significant coral concentrations in the Pribilof Canyon.
Four months later, AFSC’s stereophonic camera started snapping underwater images at a rate of one per second.
“We based the location of the camera drops on our model,” explains Chris Rooper of the AFSC and developer of the new model. “Inputs to the model were things we knew coral needed, for instance water depth, long term average temperature, general bathymetry, roughness of the bottom, that sort of thing.
“We also looked at currents, how food was being delivered to these animals, and all the trawl survey catch and bycatch data,” says Rooper. This became the framework for what’s known as a General Additive Model, or GAM model.
“Once the model is made, we lay it over map of the area, and the rest is statistical methodology. The model fit the data pretty well,” Rooper said. “It explained 50-60% of the variability in the data set.”
The photos were the final phase of a three-year, $2.4 million coral research program conducted by NOAA in Alaska.
This story originally appeared on Seafood.com, a subscription site. It is reprinted with permission.