About a salmon farm in the north of Norway

When driving through Norway you will probably notice those fish cages every now and then in the fjords or close to the sea. Well, Norway is the biggest producer of salmon by aquaculture in the world and it’s the second biggest business after oil in general in that country. So of course I have visited a fish farm at the Vesteralen and enjoyed a very informative afternoon (www.akvakulturivesteralen.no).

(Un-)Fortunately I have been the only one who booked a tour on that specific day. So once again I had a very individual and private guided tour, which started in a very modern exhibition area. Sverre, my guide, explained everything about salmon and trouts, the sorts of fish which are mainly held in their farm, the history and the way their fish is breeded, reared and processed in the end. It takes about 2,5 years for the Norwegian salmon to reach a weight about 4-5kg. In comparison to that – in nature it would take about 9 years for a salmon to gather the same weight. But through efficient feeding as well as the safe environment it’s possible to shorten that time that much.

The rearing of the fish is done at 6 central places in Norway, which deliver the eggs to all the farms. It’s a very complicated business to breed salmon in an efficient way. In nature a female salmon is spawning about 3.000 eggs in a river and it’s highly likely that just one of them survives. At a fish farm about 80-85% of the eggs survive and become 2,5 years old. On the other hand it’s also a very comforting business to breed salmon hence the eggs are of a bigger size then for example cod. That makes it easier to raise them. That’s why it is almost impossible to have cod fish on farms as their eggs are way too small to handle.

So after the eggs hatch they are spending a few weeks on trays which are permanently enriched with fresh water. They stay at the ground, sap their energy to grow from reserves out of the former egg until they are strong and old enough to come up. They are already young salmon then and in the size of a few centimeters. They are still not capable of salty water and need to grow a bit further and adjust their organs, skin color etc. to be able to survive at the sea. After about six months the salmon does change it’s color and also behavior so the farmers make sure with some additional tests that the fish is now ready for the sea. Each salmon receives a vaccine before and will be lead into a fish pen then. One farm has about 8-10 of those pens, which measures a circumference of 200 meters and a depths of 50 meters. Each contains about 160.000 fish. Norwegian regulations require that those pens are just allowed to contain 2,5% of fish which means that 97,5% needs to be water to give the fish enough space to swim in. Besides that there are loads of other restrictions to make those fishing farms as harmless as possible to the environment and the surrounding nature. There has been some major issues in the past but many of them could already be fixed and the farms are continuously working on improvements. For example has the process of feeding the fish improved a lot. Before a certain amount of food was spread into the pens from above. Most of it sank to the ground because the fish weren’t able to consume it that fast. That caused a lot of sediments on the ground, which are already overloaded by all the excrements of the fish. That again caused a lot of changes in the ecosystem around in a negative way. That’s why the feeding of the fish is controlled by cameras today (there are three cameras for each pen, over and under the water). Interesting fact – for each kilogram the salmon gains in weight, 1.2 kg of fish feed is required. So a fish consumes just 6-7 kilograms of feed during it’s lifetime. That makes salmon production very efficient (in comparison: 8kg of food os required to produce 1kg of beef).

Also the composition of the food improves continuously – the fish farms are working on an environmental friendly production of that food as well. Also the treatment of diseases has improved during the last years. Salmons offen suffer of parasites and in the past it was quite normal to treat them with pesticides. Nowadays they try to get rid of them by a special „washing“ method of the pens by dropping each salmon in hot (30 degree) water for about 20 seconds which kills the parasite but doesn’t harm the fish. The farms are also keeping another sort of fish within the pens which are natural enemies of those parasites. 

So after 2,5 years the salmon or trout is harvested and will be ready to be exported to over 100 countries just within 2 hours. Norway produces 1,3 million tons of salmon per year and wants to expand the production. Hence all the suitable places for fish pens within the fjords are already taken there are some innovations ongoing to locate them outside at the sea.

After the guided tour Sverre showed me the fish pen more closely by driving out by boat. It was very impressive to see the big swarm of fishes swimming around those pens, many of them jumping at the same time. The water was crystal clear and the fish almost ready to be harvested. 

After we drove back I had the joy to try different sorts of smoked salmon and trout. Very delicious! A perfect end for an afternoon at a fish farm. I enjoyed it a lot and learned many more things about this kind of business. Thanks Sverre for showing me around 🙂


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