Norwegian farmed salmon threatens Iceland’s wild salmon population, says Marine Research Institute report

The increased farming of salmon in sea cages (sjókvíaeldi) is considered a threat to the status of the wild salmon population. Last year saw the highest number of farmed salmon from Norwegian origin identified in Iceland, and these salmon were caught in more rivers than ever before. The report by the Marine Research Institute on the impact of sea cage farming on Icelandic salmon stocks last year showed these findings.

The success of the institute’s countermeasures to prevent the spawning of escaped farmed salmon is uncertain. The report states that the frequency of escapes from sea cage farming in the country and the number of escaped salmon that was identified last year was higher than expected.

The ultimate goal is to catch two-year-old salmon in the fall to assess their spawning and how much they have mixed with wild stocks. It is known that salmon from other countries seek feeding grounds here, and therefore it is possible that wild salmon, or farmed salmon from other countries, enter rivers here in Iceland.

The increased vigilance due to the impact of sea cage farming on Icelandic salmon stocks can be divided into several aspects: monitoring with fish counters, identification of damaged escaped salmon from farms in rivers, origin analysis of salmon with egg studies, and research on genetic mixing. The report outlines these aspects along with the main findings of the research up to 2023.

Considerable experience has been gained regarding the extent and actions of surveillance. The report says that this year’s surveillance is the fourth since the extent of salmon farming in sea cages began to increase here in the country.

The Directorate of Fisheries initiated countermeasures to reduce the likelihood of farmed salmon being able to spawn. Fishing associations were given permission to fish for farmed fish, and in some cases, the migratory routes of salmon were closed. Norwegian surface diving specialists searched for farmed salmon and removed them from the rivers.

The report states that alongside the increased farming of salmon in sea cages, there are risks that are believed to threaten the status of wild salmon stocks here in the country, such as genetic mixing.

In 2023, the situation was very different from previous years and was characterized by the escape of salmon from a cage in Kvígindisdal in Patreksfjörður in late August. The estimated number of salmon in that escape was about 3500 fish.

Shortly after the escape, farmed salmon began to appear in rivers as mature salmon seek rivers to spawn and thus end their life cycle.

The report states that the countermeasures have been successful. This fall, the plan is to catch two-year-old salmon to assess the spawning of escaped salmon, their presence, and mixing with wild salmon stocks.

The Marine Research Institute says it’s important to strengthen wild stocks to increase their resistance in the rivers of the country. The migration of wild salmon has been decreasing in recent years, and therefore the chances of the effects of mixing are considered greater if the spawning stocks of wild salmon were larger.