Biological Aspects of Massachusetts Groundfisheries

The waters off the Massachusetts coastline provide some of the best groundfish habitat in the world. However, groundfish stocks have experienced a dramatic decline over the past 30 years, largely because of overfishing. Populations of the three major commercial species, cod, haddock, and yellow-tailed flounder, have declined by as much as 80% (Massachusetts Environment). As a result, the fishing industry and the government are seeking new management strategies which will allow stocks of groundfish to recover and will promote sustainable use of these fisheries. Ideally, the result of responsible management will be the preservation of both biodiversity and of fishing as a way of life.

Historically, one of the most productive fisheries has been an area known as George's Bank located 120 kilometers off the Massachusetts coast. This area is home to over 100 species of fish as well as many species of marine birds and mammals. The high productivity of George's Bank is due to the mixing of Arctic and Gulf-stream waters that occurs there. The nutrients in the Arctic water and the warmth of the Gulf-stream water provide ideal habitat for phytoplankton, which provides excellent food for fish. The rate of phytoplankton growth on George's Bank is estimated to be 3 times as high as that of any other continental shelf (Woods Hole Oceanographic Institute).

In recent years, there have been two major declines in Atlantic groundfish stocks which have prompted interest in the protection of this marine resource. In the 1960's and early 1970's, groundfish stocks were being overexploited by foreign fishing vessels. After the passage of the Magnuson Act in 1976, American fishers began using larger boats and more advanced gear in order to harvest the fish that were previously caught by foreign ships. The size of the American fishing fleet increased from 650 to 1021 boats in a period of 7 years. The most common methods used by the new American ships were otter trawls, gill nets, traps, and set lines (Randolph T. Holhut).

One side-effect of the increased capacity of these new vessels was a dramatic increase in fishing mortality. From 1976 to 1984, groundfish landings increased by 94%. As much as 70% of the fishable populations of some species were being caught. Juvenile fish were endangered by the small mesh size of the nets and the use of bottom-scraping trawl nets on the larger boats. Trawl nets disturb the substrate which is important foraging habitat for the juveniles of many groundfish species (Environmental News Network).

Another consequence of using larger boats was a larger proportion of bycatch. On George's Bank, the abundance of species results in schools comprised of many different kinds of fish. Therefore, in order to catch the target species, fishers must sweep many bycatch species into their nets as well. The undesirable fish are then discarded, many of them dead or dying (National Marine Fisheries Service).

The problem of bycatch has become significantly worse as commercial groundfish stocks have declined. According to the Massachusetts Groundfish Taskforce, in 1975, 70% of an average catch was commercially desirable groundfish and 30% was undesirable fish, also called "trash" fish. By 1995, the ratio had switched to 70% trash fish, primarily dogfish and skates, and 30% desirable groundfish (Randolph T. Holhut).

One proposed remedy for the depletion of groundfish stocks is to increase usage of these under-utilized species which are currently being discarded. Theoretically, if fishers begin focusing on under-utilized species instead of cod, flounder, and haddock, the populations of groundfish will be able to recover. However, fishing for these species should be done cautiously as well. These fish often comprise an important link in the foodchain and overexploitation of their stocks could have detrimental effects on the marine ecosystem.

Management practices which are currently in place in Massachusetts include restrictions on net mesh sizes, minimum fish lengths, and area closures. Due to the depleted state of the George's Bank fishery, 9600 square kilometers of the fishing grounds were closed in 1994. Another management proposal currently under consideration would limit the number of days boats can be at sea (National Marine Fisheries Service). The New England boat buyback program is also expected to help alleviate some fishing pressure. Nonetheless, Massachusetts groundfish stocks are in a very fragile state and whether or not they will be able to recover is still uncertain.

The Biological Perspective of fisheries management

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