August 16, 2007
UK conducts study on how farmed salmon affect wild population fertility
Scientists at the University of East Angli in the UK are studying the implications arising from couplings between farmed and wild salmon.
The researchers will measure the fertilisation compatibility between farmed and wild salmon, thus enabling them to assess the risk of farmed genes entering wild populations.
Currently, more than 95 per cent of Atlantic salmon in existence are of farmed origin.
An estimated two million farmed salmon escape and enter the North Atlantic each year, equalling the number of wild fish.
Currently, an average of 11-35 percent of salmon in Norwegian rivers are of farmed origin.
Wild Atlantic salmon stocks have undergone a dramatic decline in recent years through over-fishing and human destruction of salmon habitats. Although it is believed that mixing of wild and salmon genes would irreversibly affect the wild population as more farmed fishes escape and mix with the wild population, there have been scant evidence to support this.
The team hopes to shed light on fertilization compatibility between farmed and wild fish that could allow policy makers to make more informed decisions for both aquaculture and salmon conservation.
The three-year study received funding of GBP 330,000 from the Natural Environment Research Council and the field work would be carried out at the Norwegian Institute of Nature Research and at hatcheries in Scotland.
Research tem leader Dr Matthew Gage, from UEA's School of Biological Sciences said repeated releases of new genetic strains into an already stressed wild population could lead to 'genetic swamping' and the complete dilution of wild genes.'
One potential problem posed by farmed fish is the species inability to adapt to wild conditions and when their genes are passed down, the same may be seen in the progeny. Another concern is that the genes from farmed salmon come from a selectively chosen and small pool of genes, making them weaker compared to wild populations.
