Aquaculture has had a tremendous growth since the end of the 70s. Because of this rapid growth we now contain huge amounts of farmed fish in netpens along the Norwegian coast. 

One of the farming industries greatest environmental challenges is the fact that each year large quantities of farmed fish escape from seafarms. The escaped farmed fish pose a threat to wild populations of salmon and trout. Norway has a special responsibility, also internationally, to conserve the unique natural values that these stocks represent.

Each year escaped salmonids from farms amounts to about the same number as the number of wild salmon returning from sea to spawn in the rivers.

A threat to wild populations

Escaped farmed could affect the wild populations both ecologically and genetically. Examples of ecological consequences would be competition related to food and spawning. Escaped farmed fish has been observed digging up and destroying the wild salmons established spawning beds. Farmed salmon can also breed with wild salmon. In this way, the new generation of wild salmon, whose traits have developed over thousands of years of evolution, will be genetically mixed with genes from a more uniform farmed species. In the long run, this may change the wild salmons to the extent that it no longer will be able to survive in its original environment. Dense concentrations of fish in netpens provide a favourably environment for diseases and parasites. Infected fish that escape farms can infect the wild populations.

To much escaped farmed fish

In 2006 it was set a new record for the number of escaped farmed salmonids. A total of 935,000 escapees where reported to the authorities. If we include unreported escapes the total number have been estimated as high as five times greater then what was reported. In 2007 the escape of salmon and trout was reduced to 618,000 individuals. Rainbow trout accounted for 315,000 individuals of this. The Norwegian Authorities long term goal is that the number of escapes should be significantly reduced to a level where it does not pose a danger to wild populations. The short term goal is to reduce the escape to 200,000 individuals.

The number of reported escaped farmed salmonids in Norwegian aquaculture (1998 to 5th October 2009)

Source: The Norwegian Directorate of Fisheries

In 2004 the Norwegian government implemented new regulations for the fish farming industry. The NYTEK-regulation sets requirements for the technical standard of farms. Regulations also require management plans to ensure good routines and internal control systems on the farms. The government also established a regime called national salmon fjords. This regime is meant to restrict salmon farming activities close to important wild salmon rivers. Despite of these regulations the number of escaped farmed fish has not yet declined.

Escape must be reduced sharply

Today’s situation is not sustainable. Too much fish are escaping from Norwegian fish farms and the damage to wild populations is unacceptable. The main proportion of escaped fish is caused by failure at farms as a result of bad weather. Poor weather conditions are not an acceptable excuse except in extreme situations. The Norwegian coastline is rough and those who want to engage in farming activities must ensure that their facilities can withstand the occasional storm.

Good practices for monitoring, inspections and maintenance of the farm is critical to prevent escapes. There is a constant technology development in the aquaculture industry. If these improvements are adopted they can reduce the risk of escape. But new equipment costs and in general the industry has shown little interest for this unless it comes in the form of legislation from the authorities. However the NYTEK-regulation resulted in an almost 5 billion NOK upgrade of the technical standard on Norwegian farms the last three years. Hopefully this will reduce the number of escapees in the years to come.