Transfer of freshwater-resident salmon from Sweden: Assessment of the risk to biodiversity and fish health in Norway

VKM shall assess the safest way to transfer individuals from the “Vänerlax” population of salmon, whether through transfer of eggs, fry or mature fish.

The Norwegian Environmental Agency has requested the assessment, in collaboration with the Norwegian Food Safety Authority.

Background

The assessment is the last part of an interregional project with Norway and Sweden evaluating the possibility of reestablishing the Vänerlax in Norway. This salmon, which use Lake Vänaren in Sweden as its feeding ground, originally spawned in the entire river Vänern, and in the Klaraälv/Trysil/Femund watercourse in Norway. However, establishment of hydropower stations in the 1900s has cut off the spawning migration into Norway. In the project three different methods for reestablishing the Norwegian population are proposed:

• Import of fertilized eggs, to be kept in a local aquaculture facility before their release into the river as either eggs, fry or juvenile fish.
• Use the Norwegian gene bank to establish a broodstock population with documented origin in an aquaculture facility. From this facility, eggs can be planted directly in the river, or eggs can be exported to local aquaculture facilities for later release as fry or juvenile fish.
• Catch of spawning fish from the lower parts of the watershed, for import and sanitation before release on the Norwegian side of the border.

Mandate

VKM shall assess whether the import of Vänerlax to Norway poses a risk to biodiversity from the introduction of alien organisms, and particularly pathogens and parasites. All three of the proposed methods for reestablishment are to be assessed.

The project group

The project group consists of:

• Eva Thorstad – Member of the VKM Panel on Alien Organisms and Trade in Endangered Species (CITES) and Chair of the project
• Gaute Velle – Chair of the VKM Panel on Alien Organisms and Trade in Endangered Species (CITES)
• Tor Gjøen – Member of the VKM Panel on Animal Health and Welfare
• Åse Helen Garseth – External expert from the Norwegian Veterinary Institute
• Snorre Gulla – External expert from the Norwegian Veterinary Institute
• Håvard Lo – External expert from the Norwegian Veterinary Institute
• Tor Atle Mo – External expert from the Norwegian Institure for Nature Research (NINA)
• Martin Malmstrøm – Project manager from the VKM Secretariat

The VKM Panel on Alien Organisms and Trade in Endangered Species (CITES), supplemented with representatives from the VKM Panel on Animal Health and Welfare, is responsible for the risk assessment. The assessment is scheduled for publication in the spring of 2021.