Salmon and trout are the two major aquaculture species in the Arctic, farmed by a high tech industry employing advanced equipment, in many ways more akin to pig or poultry farming than to fishing. Norway has developed a large industry over the past two decades and is now the world's largest farmed salmon producer. Total production in 2000 was valued at 1.6 billion US dollars, making salmon the single most important species in terms of economic value in the Norwegian fishing industry. Slightly warmer water might be expected to increase fish growth rates but any more than slight warming could exceed the temperature tolerances of farmed species. In addition, warmer waters would have other negative effects, such as an increase in diseases and toxic algal blooms. If the Atlantic waters that run north along the coast of Norway warm by a couple of degrees, aquaculture operations would probably have to shift northward, incurring significant costs. Aquaculture in marine systems off Newfoundland and Labrador is problematic due to their latitudes. It is not uncommon for the temperature in the upper water layers to rise above the tolerance of many of the species currently cultivated.

The aquaculture industry depends on a huge supply of wild fish captured from the open ocean to provide the fishmeal and oils that are important dietary components of farmed fish such as salmon and trout. The quantity of supplies needed is so high that the industry is sensitive to rapid fluctuations in important wild fish stocks, and such fluctuations can be brought about by climatic factors. For example, El Niño events in the Pacific Ocean have already affected the industry through huge impacts on anchovy stocks. From 1997 to 1998, the global anchovy fishery was reduced by nearly eight million tonnes, mainly due to El Niño. Furthermore, many species now harvested elsewhere to provide fodder for farmed fish are also highly important in the diet of wild stocks that are of much greater commercial value but which are presently not abundant due to overfishing. Should fisheries managers succeed in enlarging these wild stocks, large reductions might be needed in the fish farming operations that currently turn these important prey species into fishmeal and oil.

Aquaculture in the Faroe Islands

The ocean surrounding the Faroe Islands is part of the most important feeding grounds for wild stocks of northern European Atlantic salmon. The islands of this archipelago are loosely clustered, and have short fjords and inlets, creating a relatively open area with pronounced ocean currents that prevent water stagnation. This offers good conditions for farming Atlantic salmon and rainbow trout, by far the most prominent farmed species. In the 1980s, fish farming became an industry in the Faroe Islands, with annual production reaching about 8000 tonnes by 1988. In the early-to-mid 1990s, the industry collapsed because the numerous small fish farms could not survive the large drop in the market price of farmed salmon. Fish diseases also played a role in the collapse. Production increased again in the late 1990s, and in 2001, Faroese fish farming was consolidated into a few large companies that now operate at 23 sites. There is now a fish farm in nearly every suitable bay and fjord in the archipelago.

The Faroe Islands have become an important international player in salmon farming, harvesting a record 53 000 tonnes (gutted weight) of salmon and rainbow trout, valued at about 180 million US dollars in 2003. With a population of approximately 45 000 people, this corresponds to a production of almost 1200 kilograms of farmed fish per person. More than 300 people are directly employed on Faroese fish farms. In addition, a work force of 1000 is employed in processing and transporting fish, manufacturing fish food, and other related industries. In recent years, aquaculture has become of greater importance to the Faroese economy than in any other country. In 2001-2003, fish farming products constituted approximately 25% of total earnings from exported goods. Wild marine fisheries products constitute the only other major export, accounting for approximately 70% of the earnings from exported goods.

However, aquaculture faces growing problems. Financial strains are increasing due to salmon diseases and the large reduction in market prices. Some untreatable diseases, notably infectious salmon anemia and bacterial kidney disease, occur with unusual frequency in the Faroe Islands. The industry needs an influx of capital if they are to continue the high level of production of recent years and the problems with diseases and low market prices make such an influx unlikely. It has thus been predicted that production during 2004-2006 will drop as shown in the figure. A warming climate can have both positive and negative effects. If warming does not exceed about 5°C, fish growth rates and the length of the growing season are expected to increase. Greater increases in temperature could exceed the thermal tolerance of the fish. Warming also tends to increase incidence of fish diseases and toxic algal blooms.