Georges Bank (Collapse of the Ground Fishery)
Georges Bank (collapse of the ground fishery)
Until the 1990s Georges Bank, off the coasts of New England and Nova Scotia, was one of the world's most valuable fisheries. A bank is a plateau found under the surface of shallow ocean water. Georges Bank is the southernmost and the most productive of the banks that form the continental shelf. A majority of the $800 million northeastern fishery industry comes from Georges Bank. The oval shaped bank is 149 mi long and 74.5 mi wide (240 km by 120 km). Georges Bank covers an area larger than the state of Massachusetts. The ocean bottom of Georges Bank formed ideal habitat for favorable quantities of groundfish, demersal finfishes, fish which feed off or near the ocean's floor mdash; cod, Gadidae, clam, Pelecypoda, haddock, Melanogrammus aeglefinus, hake, Merlucciidae, herring, Clupea harengus, lobster, Homarus, pollock, Pollachaius, flounder, and scallops, Pectinidae. But by 1994 the Georges Bank ground fishery had collapsed.
Cod were by far the most numerous and valuable of the Georges Bank's fish. Atlantic cod form distinct stocks and the Georges Bank stock grows faster than those of the colder waters further north. They are the world's largest and thickest cod. In 1938 a cod weighing 180 lb (82 kg) was caught off the bank. The cod move in schools from feeding to spawning grounds, in dense aggregates of hundreds of millions of fish, making them easy prey for fishing nets.
During the second half of the twentieth century, gigantic trawlers towing enormous nets could haul in 200 tons (181.4 metric tons) of fish an hour off Georges Bank. At its peak in 1968, 810,000 tons (734,827 metric tons) of cod were harvested. By the 1970s, fleets of Soviet, European, and Japanese factory ships were trawling the cod-spawning grounds, scooping up the fish before they could reproduce. If the catch was of mixed species or the wrong size, the nets were dumped, leaving the ocean surface teaming with dead fish. After the catch was sorted, many species of dead bycatch , including young cod, flounder, and crabs, were discarded. For every three tons of processed fish, at least a ton of bycatch died. These ships also trawled for herring, capelin, mackerel, and other small fish that the cod and other groundfish depend on for food.
The Fisheries Conservation and Management Act of 1976 extended exclusive American fishing rights from 12–200 mi (19–322 km) offshore. Since much of Georges Bank is within the 200-mi (322 km) limit of Nova Scotia, conflict erupted between American and Canadian fishermen. International arbitration eventually gave Canada the northeast corner of the bank. The legislation also established the New England Fishery Management Council to regulate fishing. Although the goal was to conserve fisheries as well as to create exclusive American fishing grounds, the council was controlled by commercial interests. The result was the development of financial incentives and boat-building subsidies to modernize the fishing fleet.
Soon the New England fleet surpassed the fishing capacities of the foreign fleets it replaced and every square foot of Georges Bank had been scraped with the heavy chains that hold down the trawling nets and stir up fish. This destroyed the rocky bottom structure of the bank and the vegetation and marine invertebrates that created habitat for the groundfish. Cod, pollack, and haddock were replaced by dogfish and skates, so-called "trash fish."
During the 1990s tiny hydroids, similar to jellyfish, began appearing off Georges Bank, in concentrations as high as 100 per gal of water. Although they were drifting in the water, they were in their sedentary life-stage form, indicating that they may have been ripped from their attachments by storms or commercial trawlers. These hydroids ate most of the small crustaceans that the groundfish larvae depend on. They also directly killed cod larvae.
In 1994 the National Marine Fisheries Service found that the Georges Bank cod stock had declined by 40% since 1990, the largest decline ever recorded. Furthermore, the yellowtail flounder stock had collapsed. In a given year, only eight out of 100 flounder survived and the breeding population had fallen 94% in three years. The last successful flounder spawning was in 1987; but 60% of the catch from that year's group were too small to sell and were discarded. In response the Fisheries Service closed large areas of Georges Bank, but fishing continued in the Canadian sector and western portions of the American sector. With the goal of annually harvesting only 15% of the remaining stock, each vessel was restricted to 139 days of ground fishing. Nevertheless by 1996, 55% of the remaining Georges Bank cod stock — the only surviving North Atlantic population — had been caught. Fishing was restricted to 88 days. A satellite-based vessel monitoring system is used to detect fishing boats that enter closed areas of Georges Bank.
At the time of the cod moratorium, it was argued that the population would recover in five years; however there were few signs of recovery as of 2002. Not only is the cod stock near an all-time low, but so are populations of other commercial fish and many other species. The average size of the bottom-dwelling fish of Georges Bank is a fraction of what it was twenty years ago.
Georges Bank is just one example of a eastern coastal area negatively affected by excessive trawling. Even though there is $800 million worth of fish extracted from Georges Bank and the surrounding area, there is an overall decline in groundfish stock along the entire boreal and sub-arctic coast of eastern North America. American and Canadian moratoriums on gas and oil exploration and extraction from Georges Bank—activities that could further disrupt the fishery—are in effect until at least 2012.
[Margaret Alic Ph.D. ]
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Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA USA 02543-1026 (508) 495-2000, Fax: (508) 495-2258, , <http://www.nefsc.nmfs.gov>