With farmed salmon having escaped into rivers in Iceland, genetic changes have occurred in the country’s wild salmon stock. This is indicated in a new study of the salmon in Elliðaár in Reykjavík, recently published in the science journal Conservation Genetics.
Head of the Directorate of Fisheries Sigurður Guðjónsson, a co-author of the study, told Fréttablaðið that the main conclusion is that the genetic mix of farmed and wild salmon must be prevented by all possible means.
“We have long warned of this risk,” said Sigurður. “When the first wave in salmon farming started … a considerable amount of farmed salmon escaped into Elliðaár. The study shows that the wild stock was impacted. Our researchers found hybrids.”
The study, which compared scale samples from salmon in the three rivers that make up the Elliðaár river system, collected in 1948, 1962, 1990 and 2005, showed that each river had a different salmon stock originally.
However, after farmed salmon started mixing with the wild salmon in the rivers, the difference between the stocks gradually decreased and eventually disappeared.
Salmon farming in marine pens is currently banned in areas where there are large salmon rivers, such as in Faxaflói and Breiðafjörður in West Iceland and off North Iceland.
Extensive salmon farming with salmon of a Norwegian breed is being planned in the West Fjords which has caused debate, not least because of the salmon rivers that run into Ísafjarðardjúp in the northern part of the region.
Sigurður said there is a risk that salmon may escape the pens and enter rivers. “How distantly the salmon is related [to the Icelandic salmon stock] is also a factor and therefore the Norwegian salmon is more dangerous.”
“The arguments for using specially-bred farmed Norwegian salmon are all about how easy it is for breeding but the counterarguments concerning nature have less weight,” Sigurður stated.
The study was carried out by the Directorate of Fisheries, University of Iceland, the Icelandic Marine Research Institute, independent research institute Matís and the University of Idaho.
Its main author is Leó Alexander Guðmundsson, a specialist at the Directorate of Fisheries.