Northeast Consortium, University of New Hampshire, Woods Hole Oceanographic Institution, University of Maine, Massachusetts Institute of Technology
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Red Crab Stock Assessment Project

The Red Crab Stock Assessment Project: Industry-Initiated Resource Protection

 

By Rachel Gallant
Fisheries Specialist, Northeast Consortium
June 15, 2004

 

Until the summer of 2003, the New England deep sea red crab (Chaceon quiquedens) was one of the last unmanaged fisheries in the Northeast, but the pressure to develop a fishery management plan came not from environmental groups, the government, or scientists, but from crab harvesters themselves.

 

Fisherman Jon Williams of Westport Island, Maine and others within the New England Red Crab Harvester’s Association foresaw increased pressure on the deep sea red crab fishery in the mid-1990s. That was when Alaska’s king crab fishery collapsed and Alaskan fishermen began to look elsewhere for harvesting prospects. Local fishermen began to petition the New England Fishery Management Council for a management plan that would curb the potential for over harvesting if more boats entered the fishery.

 

On a 2003 cruise, the research team relaxes by the camera sled. Left to right are Frank Rizzo, John Brewer, Lindsay Routt, Rick Wahle, Michael Dunnington, and Jon Williams. (Photo courtesy of Rick Wahle)

The Council responded, implementing emergency regulations such as trip limits, control dates, and gear restrictions, even though decisions had to be made with little scientific justification. Good stock assessment data for the red crab just did not exist; the “best available science” for New England’s deep sea red crab was a survey from 1974!

 

Williams saw the need for updated data and approached Dr. Richard Wahle, a crustacean biologist at Bigelow Laboratory for Ocean Sciences in West Boothbay Harbor, Maine and Dr. Yong Chen at the University of Maine. Together, with funding from the Northeast Consortium, they are now well into a multi-year red crab research program that will help make sure a good fishery management plan is in place.

 

After preliminary equipment trials at sea, their first multi-day research cruise was in June 2003. They are using cameras and towed gear to determine stock abundance, size structure, and sex composition. They are finding that most red crabs live at about 350 fathoms; that is about 240 fathoms below where sunlight can penetrate into the ocean! Now, over 5,000 red crab have been tagged to measure growth rates, which is key to understanding the maturity of the fishery and calculating sustainable harvest rates. They expect to tag about 5,000 more this summer.

A mature male with a small blue survey tag on right side. (Photo courtesy of Rick Wahle)

 

At first glance, the Wahle-Williams-Chen team is finding that there may be higher population densities now than in 1974, but fishing pressure is evident, because there are fewer large males. The sex ratio for red crab of harvestable size is now less than 1:1, but is still 1:1 for smaller crabs (only large males are taken in this fishery). A closer look at the data, including the use of Chen’s population models, will determine if current catch rates are sustainable in the long term.

 

Management has been involved with this project all along. The Council’s staff for the Red Crab Technical Committee, Deirdre Boelke, keeps in touch with the research team, so that the Committee can stay updated on the project’s findings and help incorporate them into the management process where applicable. Also, Williams serves on the Red Crab Advisory Panel and Wahle recently joined the Red Crab Plan Development Team.

 

Williams credits the Council and staff for recognizing the imminent threat to the fishery and for taking necessary and timely steps to protect the resource. “ There is no doubt in my mind that the red crab fishery would have been destroyed had it not been for the New England Management Council,” he states.

 

The “Holy Grail” for Wahle would be to one day know where the juveniles are settling, which may be occurring just out of their reach. Wahle notes, “We’re maxed out on cable length!” He suspects that they are in deeper waters than he is capable of sampling right now (500 fathoms).

 

For now, these researchers will just have to settle for knowing that they are directly helping inform the management plan for (and thus the future of) these crustaceans of the deep. That can hardly be considered settling for less!

 

For more information, go to this project’s own website at: www.bigelow.org/srs/redcrab_index.html