Aquaculture is the fastest growing food sector in the world. In the Arctic sealice, contaminated discharge, and escaping fish remain problems. By Dag Nagoda and Maren Esmark
More stable and predictable production volumes, as well as large markets in the EU and the US, are among the advantages of aquaculture, the farming of marine organisms, seen from a business perspective. There is already a large salmon and trout industry in northern Norway. In northwest Russia there is some production of salmon, rainbow trout and mussels. The Russian market for seafood is growing, and both the Norwegian and Russian governments advocate further development of aquaculture in the Barents Sea Region.
Impacts of aquaculture on the Arctic environment
If properly regulated, aquaculture can provide good opportunities for local development without large impacts on the ecosystem. Poorly managed and poorly regulated aquaculture, however, can have severe negative impacts through the release of excessive nutrients and chemicals, as well as escapes of farmed fish and the risk of disease transfer. The expansion of the aquaculture industry gives rise to two overriding concerns: the intrusion of fish farms into vulnerable marine and coastal areas, and the overall sustainability of an industry that depends on large catches of wild fish to feed farmed fish
|poorly managed and poorly regulated aquaculture can have severe negative impacts through the release of excessive nutrients and chemicals, as well as escapes of farmed fish
In the Barents Sea there are different types of aquaculture. Mussel farming is conducted in sea, with natural seeding, and apart from potential local conflicts with seabirds, this production has no significant environmental impact on the marine ecosystem. On-shore fish farming of species such as charr and trout is possible in Arctic areas, even in low temperatures, if clean water and energy for heating is available. Environmental impacts of such production are limited. However, Fish farming in the Arcticthe extraction of freshwater from rivers can have severe impact on the river habitat. Discharge of waste water can contain harmful concentrations of nutrients, chemicals and be a potential source for infection of, for example, the lethal salmon parasite Gyrodactylus salaris.
Less discharge – for now
The most common aquaculture production in the Barents Sea is that of open sea cage farming of Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Improved farming techniques over the last ten years have severely cut the amount of nutrients released from such farms and good monitoring systems address local impacts on bottom
habitats. However, sufficient regulations for controlling cumulative effects of several farms in one area are missing. The use of antibiotics has been significantly reduced, but might increase as new species are developed and new diseases appear. Copper is toxic to marine organisms, and is used as an anti-fouling agent on nets. As the industry grows, so does the total discharge of copper.
600,000 escapees a yearThe total number of escaped farmed fish in Norway in 2002 was 630 000 salmon and trout. Ecological impacts of escaped fish are mediated through habitat and feed competition, genetic pollution and the spread of parasites and infectious diseases. Historically, the amount of escaped fish has been low in Troms and Finnmark county. However, the numbers for 2002 shows that at Kinn, in Troms/Nordland, there was an alarming 48 percent of farmed fish caught in the sea fishery. In the Altavassdraget (Altariver) the catch included 20 percent escaped fish in 2002.
Sealice infect the fish
Sealice is another problem connected with fish farming. The louse is a marine parasite, naturally occurring on salmonids. More than ten lice can be lethal to migrating smolts. The millions of farmed fish that stay in coastal areas all year round now serve as a host for the sealice and can be a reservoir for the parasite. In 2002, results from Møre and Romsdal County up to Finnmark County show that infections of sealice are significant, and are likely to affect local stocks of seatrout and Arctic charr.
Indirect impacts on wild fish stocks
Because most species used in marine fish farming are carnivores, fish farming causes a high demand for fatty and protein-rich fish feed. Most fish species used for fish feed are important for the marine ecosystem, as they are prey for fish, birds and mammals. In Norwegian fish farms, 1 kg of farmed salmon requires 3–4 kg of wild caught fish. Species occurring in the North Atlantic, such as capelin, herring, Norway pout and blue whiting are frequently used in fish feed. An expansion of the aquaculture industry in the Arctic will therefore increase pressure on wild fish stocks.
Given the increasing interest in aquaculture in the Barents region and its potential negative impacts on the ecosystem, the mitigation measures undertaken in the future will decide if the industry develops in a sustainable fashion or turns into a new major threat to the biodiversity in the Barents Sea.
DAG NAGODA is the Barents Sea Coordinator and MAREN ESMARK is the Marine Conservation Officer at WWF-Norway.This text is part of a large report to be published in November 2003 by WWF, A Biodiversity Assessment of the Barents Sea Ecoregion. Please contact WWF’s Barents Sea Program for more information at + 47 22 03 65 00 or email@example.com