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Methods to Reduce Escapes and Identify Escapees

07 March 2012

GLOBAL - Escaped farmed salmon are a major problem for the aquaculture industry. There impact on wild fish stocks is still a huge area of debate and concern.

With more extreme weather hitting the Norwegian coast, earlier this year, the Norwegian Ministry of Fisheries proposed setting a ceiling of 200,000 fish per cage.

This rule will come into force in January 2013. However, it does not have the full backing of the industry.

The ministry is also supporting schemes which encourage the production of smolts on shore.

After a number of escapes last year, Marine Harvest Norway announced earlier this year that it is testing new equipment to grow 1kg salmon smolts on land.

Whilst these measures along with the industry's commitment to reducing escapes will help, escapes are still inevitable.

This week, Nofima said that it is looking at identifying escaped farmed salmon through a mixture of physical markings and DNA tracing.

Spotting the difference between an escaped farmed salmon and a wild salmon is not always easy. But physical markings, such as clipping the adipose fin, freeze branding or colour marking of all farmed salmon, will show whether a salmon has escaped or not, without wasting time and money on DNA testing.

By using DNA markers, the scientists want to record the genotypes of the parents of all farmed salmon. If an escaped fish is captured, genotyping should reveal the correct parental match and, therefore, the responsible company.

These methods will be tested and developed through a two year pilot programme.

Some groups argue that farmed fish are too much of a risk to wild stocks.

However, overfishing of wild fish stocks is causing similar concern among governmental and conservation groups.

A total of 100,000 EU citizens having signed the World Wildlife Fund's "More Fish" petition to end over exploitation of fish stocks.

The Irish Food Board, Bord Bia has reported that the supply of global pelagic stocks was down in 2011. EU Commissioner, Maria Damanaki has put much focus on overfishing in the Common Fishery Policy (CFP) reforms.

With currently 75 per cent of EU stocks overfished, Ms Damanaki has said that the reform of the CFP is a unique opportunity to overcome once and for all the problem of overfishing.

Charlotte Johnston, Editor

Charlotte Johnston - Editor



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