The development of a successful and sustainable marine fish farming industry for species such as cod, haddock and halibut offers a valuable additional supply source for the seafood processing industry, hit hard in recent years by dwindling quotas.

In the UK, the farming of these 'new' marine finfish species is still in its infancy, with production in 2002 estimated at about 300 tonnes of halibut, 300 tonnes of turbot and 180 tonnes of cod, amounting to approximately £3.5m to £4m at first sale value.

However, the potential for growth is good. The British Marine Finfish Association (BMFA) has developed a carefully modelled 10-year target for growth, predicting a first sale production value of £100m by the end of the period, employing 600 people in high quality, full time jobs - mostly in Scotland.

The Association also believes this will stimulate upstream and downstream employment of a further 1,800 jobs. In volume terms, this equates to a combined production of 30,000 tonnes of farmed cod and haddock, with an additional 10,000 tonnes of high value halibut.

This is still a drop in the ocean compared with consumer demand and the BMFA is keen to stress that it is unlikely that the farmed product will compete with wild-caught fish, but instead will complement fleet landings by developing a niche at the top end of the retail sector. Cod, for example, will be harvested at around two kilos in size, competing with imported Icelandic fillets, not the smaller UK landed fish.

The BMFA is also keen to stress that the development of new species farming is intrinsically linked to the fortunes of the salmon farming industry,

"Salmon represents somewhere in the region of £350m to the economy and marine species can add a further £100m to Scotland plc. We need a vibrant salmon farming industry to power the development of additional species," states Alastair Barge, chairman of the BMFA.

He adds: "The west coast and northern isles of Scotland offer some of the best environmental conditions in the Northern Hemisphere for the efficient culture of cod, haddock and halibut. This optimum temperature profile - caused by mild winters and summers - offers an unparalleled economic opportunity, which must be grasped."

Sue Utting, Aquaculture Development Manager for the Sea Fish Industry Authority, agrees. "The UK supply chain is going to be sustained by production from aquaculture as well as the wild catch. We see both sources of supply as complementing each other."

Seafish has encouraged and assisted the development of marine fish farming, and research at its Marine Farming Unit at Ardtoe on the west coast of Scotland has involved pioneering work investigating the commercial viability of halibut, cod and haddock in a sustainable way.

A three-year demonstration project, which ended in 2000 resulted in the first 10 tonnes of UK farmed cod going on sale in the upmarket food section of multiple retailer Marks & Spencer. A further 35 tonnes of cod was well received by consumers, and several companies are currently involved in developing cod farms with the first fish now hitting the market.

Research is now well underway at Ardtoe on haddock, with the project in its final year. Around 18,000 juveniles were grown at Ardtoe in 2002 and these are being ongrown by fish farm producer Aquascot to determine husbandry techniques. The production of suitable diets for haddock is also being examined, and in the final year of the demonstration project hatchery rearing protocols will be refined and harvest and flesh quality assessed.

As already indicated, the main market for farmed marine fish is the top end of the fresh market, supplying fillets principally to retailers but also for the catering sector. Farmed fish offers the benefits of consistency of size and quality, along with full traceability and regular, year-round production. In independent taste tests it compares favourably with wild fish.

There is also the feasibility of farming other species in UK waters, lemon sole being one possibility. British waters are probably too cold for bass farming in ambient conditions (although wild fish do thrive in western and southern waters). However, turbot and sea bass can be grown onshore in recirculation systems at raised seawater temperatures and commercial units have been established in North Wales.

Seafish and the BMFA are committed to ensuring the sustainability of marine aquaculture, with the recognition that environmental protection is a priority. "To ensure consumer confidence, the development of marine aquaculture must be carried out sustainably and with minimal impact on the environment," says Dr Sue Utting.

Positive aspects of marine fish farming include the low requirement for fish oil. They do have a high protein requirement but this may be partially supplied by plant protein - an issue currently being researched. In addition, the fish do not suffer from lice as salmon does. Vaccines are already available and a large infrastructure is in place to deal with health and environmental issues - expertise which did not exist in the early days of salmon farming.