Help for Fishermen From the Lab
With the closing of Georges Bank, New England scientists are seeking to develop strains of fish suitable for aquaculture
Boston — When the United States Commerce Department closed major portions of Georges Bank to commercial fishing early last month, it seemed as though another of New England's most time-honored occupations had foundered.
Now, marine scientists in the region are trying to find ways to salvage some of the wreckage through aquaculture.
The approach ``never really has caught on in the United States because the fisheries have been so good,'' says David Bengsten, a zoologist at the University of Rhode Island. ``But it's clear the fisheries are declining.''
A report issued last August on Georges Bank termed the fishery there close to collapse. Species ranging from cod and haddock to yellowtail flounder have nearly been fished out, and it could take years for the populations to rebuild.
The results helped prompt the decision to shut down some 6,600 square miles of once-prime fishing areas.
While fish farms specializing in stripped bass and Atlantic salmon, which can grow in fresh water or salt water, have been operating for several years, only recently have researchers in the region begun to turn their attention to saltwater species that have helped put chowder on the table for generations of New England fisherman.
The main focus of attention is on summer flounder, a bottom-dwelling species that ranges along the East Coast from the Carolinas to southern New England. The species is attractive, Dr. Bengsten says, because of its high value in Asian-American markets. By some estimates it can fetch from $3 to $6 a pound depending on the quality.
With funding from federal grants, Bengsten and Hunt Howell of the University of New Hampshire's Marine Coastal Laboratory in Newcastle, N.H., are analyzing and in some cases trying to modify the flounder's habits to make them more suitable for farming.
One of the initial questions that had to be answered, Bengsten says, was basic: Can you raise flounder in the lab in large enough numbers to make farming a realistic prospect? In the wild, the fish spawn in the fall. The larvae drift into estuaries in the late winter and early spring to hatch. The fry undergo extremely rapid growth during the first year. In the second year, they start their reproductive careers and reach the size when they can be legally fished.
To increase the reproduction rate in the lab, ``we had to trick them into thinking that it's summer,'' Bengsten says. ``We increased the amount of light to 15 or 16 hours a day and increased the water temperature for a couple of months.'' That, combined with hormone injections, led the flounder to spawn three times a year instead of once. Ultimately, Bengsten says, he hopes to be able to eliminate the hormone treatments and rely solely on changes in light and water temperature to induce spawning.
Researchers at the University of New Hampshire are focusing on various aspects of raising the flounder once they hatch. One question: Does the color of the tank housing the fish affect the fish's color over time as the fish adapts to its new surroundings? The question is not trivial, Dr. Howell says; the market value of the fish drops if the skin is discolored.
In addition, Howell's team is trying to determine the optimal diet for flounder. For all the years the species has been fished, its nutritional requirements are not well known, he says. ``For example, we don't know the proper proportions of proteins and fats.''
This spring, his group also will begin experiments to determine the best stocking density for tank-raised flounder.
The effort is part of a $9 million federal-aid package to help the New England fishermen weather the wrenching changes their industry is undergoing. Initially, $4.5 million will be spent in three areas, says Bob Klaucke, a fisheries development specialist at the National Marine Fisheries Service (NMFS) office in Gloucester, Mass. The areas include: developing commercial fisheries with underutilized species; developing alternative job and business opportunities; and restoring groundfish stocks through aquaculture and hatcheries.
WITHIN this program, the NMFS has approved a $655,000 grant to begin work on demonstration farms in Massachusetts and Rhode Island. The money is divided between AquaFutures Inc., a Turners Falls, Mass., company currently farming hybrid striped bass. Part of the money will go to a start-up firm that will supply the flounder fry to fish farmers. The balance will go toward setting up the demonstration farms.
Josh Goldman, who heads AquaFutures, estimates that the market for high-quality summer flounder is about $20 million a year.
The research effort also has the potential to provide the basis for restocking the open-sea fisheries. George Nardy, with the New England Fisheries Development Council in Boston, points out that in Japan, from 40 percent to 50 percent of the offshore catch for Japanese flounder are hatchery-raised.
But such efforts also raise environmental concerns. ``In nature, only a small fraction of the young fish survive,'' Mr. Goldman says. ``Are flounder raised in captivity weaker, and if so, what will their introduction do genetically to the wild population?''
Flounder farming will not be a short-term solution to the fishing crisis in New England, Mr. Nardy says. It takes two to three years to bring fish to marketable size; then it may take two to three years of demonstration projects to show the investment community that it's worth underwriting, he says.
Whatever the uncertainties, some hold out hope that a workable farming technique for summer flounder could be expanded. ``Because of similarities between species, if we can get something going for summer flounder or haddock, the techniques might be transferable to other species,'' Nardy says.