To farm salmon in co-existence with wild salmon

With farms close to one of the world’s most infamous wild salmon rivers, the Alta river in northern Norway, it is Grieg Seafood’s responsibility, to use farming methods that minimize impact on the wild salmon population.


“All industries and activities that can affect the wild salmon must take their partof the responsibility. That includes us in the salmon farming industry.”

Area Manager Alta
Grieg Seafood Finnmark

“All industries and activities that can affect the wild salmon must take their part of the responsibility. That includes us in the salmon farming industry,” says Roger Karlsen.


Today, he is the Area Manager for the Alta farms in Grieg Seafood Finnmark. But his interest in salmon started long before he entered the aquaculture industry many years ago.


“I caught my first wild salmon when I was seven years old in the river Måselva in Troms, where my mother comes from,” Karlsen explains. That was the beginning of a lifelong passion for salmon.


“Since then, I have caught wild salmon almost every year.“



The number of wild Atlantic salmon returning from the ocean to Norwegian rivers has decreased significantly compared to a few decades ago. A combination of many factors and industrial activities have caused the decline, including impact from the salmon farming industry.


Salmon farming can mainly affect the wild salmon populations in two ways. First, escaped farmed salmon may genetically mix with the wild salmon in the rivers. Second, if farms have high levels of sea lice, the wild salmon may catch sea lice when they pass the


“The smolt is particularly vulnerable for sea lice when they are on their way out to the ocean,” says Roger Karlsen.

Historically, the salmon farming industry has admittedly not always been serious enough in it’s efforts to avoid impact on wild salmon. That has changed.

“Our farmed salmon must be able to live in co-existence with the wild salmon. Particularly here in Alta. Because the wild salmon river here is so special, the responsibility on our shoulders is even bigger,” Karlsen elaborates.



Grieg Seafood is mainly working on combating sea lice through preventative measures. The Company seeks to avoid treatments that stresses the fish and may cause mortalities, that can make an impact on the environment and that drive production cost.


“We work on a range of preventative measures to keep the sea lice levels constantly low. We use skirts around the pens to prevent the sea lice from entering. We use cleaner fish who eat the sea lice naturally. We also fallow over a longer period of time on some sites, which may reduce sea lice levels as well,” Karlsen explains.


Only when all of these measures fail, does the Company apply mechanical treatments to remove the sea lice. Medical treatments are used as a last resort.


Preventing escapes also needs constant work and focus. Grieg Seafood has zero tolerance for escapes. Escapes may not only be harmful to the wild salmon, it is also an economic cost for the company.


“Here in Finnmark, we have not had an escape since 2016,” says Karlsen. He explains that stricter regulations have caused investments in stronger equipment and new monitoring routines on the farms.


“We need constant focus on preventing escapes. It is about training, awareness and risk management before we conduct operations,” he elaborates.

The Alta River in Finnmark, Norway.



Grieg Seafood and the rest of the salmon farming industry in Alta have, together with the local municipality, wild salmon management actors and research institutions, started Kompetanseklynge Laks, a cluster to promote sustainable salmon farming.


“The aim of the cluster is to generate knowledge about salmon farming that can help decision makers make good and fact-based decisions,” says Per-Arne Emaus, senior researcher at Akvaplanniva and Chairman of the Board at Kompetanseklynge Laks.


Avoiding impact on the wild salmon population is a main goal for many of the projects initiated by the cluster. The organization spends 3 - 4 million Norwegian kroners annually to research interactions between wild and farmed salmon.


“We have, for example, tracked where the wild smolt swims on their way out of the Alta river and towards the sea,” Emaus explains.

The project generated it’s first conclusions in 2018.


“According to the findings so far, the smolt pass one salmon farm on the way towards the sea, at a time with low sea lice numbers. It uses an average of three days to get from the Alta river to the ocean,” says Emaus.



The salmon farming industry in Alta is also monitoring the number of farmed salmon in the Alta river and the Repparfjord river. The monitoring is organized together with Norwegian Institute for Nature Research, the management of the Alta rivers, and the West Finnmark Hunting and Fishing association.


“In this project, we encourage sports fishermen to send samples of fish shells from the salmon they catch to the Norwegian Institute for Nature Research. They analyze whether the fish is farmed or wild salmon,” says Roger Pedersen, Public Relations Manager in Grieg Seafood Finnmark.


“In 2018, none of the analyzed samples from the Alta river were farmed salmon, and 1.1 percent of the samples from the Repparfjord river were farmed salmon,” he elaborates.


Pedersen says that Grieg Seafood will continue to seek new ways of promoting co-exstence between the wild salmon and farmed salmon industry.


“These results do not in any way indicate that we are done with our work to prevent impact on the wild salmon. That continues every day on every farm. But it is good to know that we are on the right track.”