Further measures towards salmon parasites in Driva

– We can not make certain that the salmon fry which might be nonetheless within the higher elements of the Driva from earlier than the fishing barrier was established in 2017 usually are not contaminated by salmon parasites. That’s the reason we’re doing an additional spherical of chlorine therapy this summer time, says environmental director Ellen Hambro in a press launch.

The Norwegian Atmosphere Company carried out a easy therapy of elements of the higher Driva with chlorine final autumn, and following that no hint of the lethal salmon parasite Gyrodactylus salaris by DNA samples of the water.

Have stayed longer than 5 years

Nonetheless, extra therapy is required this yr, as a result of new samples present that there are nonetheless salmon fry within the higher elements of the Driva that originate from spawning earlier than the fish barrier was established.

Salmon hatchlings usually migrate to the ocean following 5 years on the newest. For the reason that fish barrier in Driva was established in 2017, the Atmosphere Company assumed that the realm above the fish barrier was empty of each salmon and salmon parasites following the second therapy of the river in 2023.

In Driva, nevertheless, it has been proven that some salmon fry have remained longer than 5 years, which the Atmosphere Company assumes is as a result of salmon rising extra slowly at altitude as a result of much less vitamin and colder water.

Final along with the Drammen area

All therapy towards salmon parasites within the river this yr will likely be carried out with the usage of chlorine, which kills the parasite with out harming the fish.

In different rivers within the Driva area, the therapy towards Gyrodactylus salaris has been accomplished, and the return of authentic salmon strains from the gene financial institution began this spring.

– Now that the rivers are freed from salmon parasites, we see the worth of getting taken care of the unique salmon strains within the gene financial institution for a few years, in order that they’ll return residence, says Hambro.

The Driva area, along with the Drammen area, are the final areas in Norway the place the salmon parasite Gyrodactylus salaris has not but been eradicated.