The wild ox is under attack!
In recent years, salmon populations in Norway have declined. In many rivers, salmon are protected. In the exhibition you can learn about the threats in text and images.
We showcase measures that help salmon and that have worked. Among other things, measures against acid rain, the salmon parasite Gyrodactylus Salaris, humpback salmon and regulation of salmon farming.
If we use resources, it is possible to preserve salmon for future generations.
The incredible life of the Atlantic salmon
Lifecycle
Egg
The female salmon bury thousands of fertilized eggs in gravel pits every autumn.
Yolk sac fry (alevin)
The fry hatch in the spring. They lie hidden in the gravel and feed on the yolk sac.
Fry
In summer, the fry emerge from the gravel and begin to eat small insects nearby.
Parr
In the fall, the fry develop into pairs. They acquire camouflage patterns and remain in the river for several years.
Smolt
When the parr reaches about 12 centimeters in length, it transforms into a smolt. Its body and organs adapt to life in the ocean.
Adult salmon
After one to three years in the ocean, the adult salmon migrates back to the river it came from. Some can weigh up to 25 kilograms. A migration of 4,000 kilometers
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Less than 1% of the Atlantic salmon in Greenland waters come from Greenland; the vast majority come from North American rivers.
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Smolt from more than 2,000 rivers in Europe and North America migrate to feeding grounds in the North Atlantic. Many find their way to the west coast of Greenland.
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After one to three years in the ocean, the salmon uses the Earth's magnetic field and its sense of smell to find its way back to the river where it was hatched to spawn.
What are the biggest threats to salmon?
In recent years, salmon populations in Norway have declined. In many rivers, salmon are protected.
What are the biggest threats to salmon?
In the exhibition you can learn about the threats through text and images.
We showcase measures that help salmon and that have worked. Among other things, measures against the salmon parasite Gyrodactylus salaris, humpback salmon and regulation of salmon farming.
If we use resources, it is possible to preserve salmon for future generations.
The Atlantic salmon is both an effective predator and an important prey for other animals. Only the strongest survive: fewer than five in a hundred smolts return from the sea to their home river.
Prey in the sea
sandeel
killifish
capelin
herring
octopus
Predators in the sea
bluefin tuna
harbor seal / seal
porpoise
striped bass
Tracking wild Atlantic salmon
Since 2003, researchers and collaborators have been following wild Atlantic salmon to solve the mystery of their migration.
Smolt and adult salmon are marked when they leave the rivers of North America and when they return from Greenland.
Receivers placed along the migration routes record fish with small acoustic transmitters. The information is stored and later downloaded.
Satellite transmitters are attached to adult salmon. These record daily movements over several months before they detach and send data back to researchers.
The salmon parasite G. salaris – an increasingly diminishing threat
Photo: Jannicke Wiik-Nielsen, Norwegian Veterinary Institute
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The tiny freshwater parasite Gyrodactylus salaris (gyro) is called the salmon killer. If a river becomes infected, almost all the salmon fry can die. In Norway, we have worked hard to eradicate this parasite, and we have succeeded in doing so in many rivers. Therefore, experts say that this threat has diminished.
This picture is actually in black and white. To help you see the details better, it has been colored. What you see is the attachment organ of the parasite. Notice the hooks!
The Drammen Waterway is currently being treated against G. salaris.
For the Drammenselva River, large-scale trials with chloramine treatment will be carried out in August-September. The dosing will take place in two stages, with the first phase on the Embretsfoss-Hellefoss stretch. Equipment and crew will then be moved downstream to treat the lower part of the river.
Based on the experience from the trials in 2025 and 2026, the final treatment recommendation will be finalized. The plan is to use chloramine as the main chemical, supplemented with rotenone in areas where chloramine is not considered appropriate.
The cultivation facilities HÃ…K
(Hokksund) and DOFA (Lier) will play a key role in the re-establishment of salmon and sea trout after the treatments. The gene bank currently houses many generations and families of fish from our waterways. These will produce eggs that will be returned to their original rivers. The visit provided useful insight into the work of the gene bank and was an inspiration for further
It is still permitted to fish for salmon and sea trout in the Drammenselva River throughout the treatment period.
Cultivation work in the Drammenselva River
