Sjørøya is a tough guy

Sjørøya har hvite prikker. Foto: Arnt Mollan

The freshwater fish that can tolerate the coldest water is the Arctic char. No freshwater fish live further north! In Arctic regions, such as North Greenland and Svalbard, there are only Arctic char. Some char live part of their lives in the sea.

The Arctic char is a freshwater fish. That's because it spawns in freshwater. Some char live their entire lives in freshwater, but some go to the sea. We call them Arctic char. Arctic char are found all around the Arctic Ocean in the northern hemisphere.

Røya was here first

Arctic char were probably the first freshwater fish to migrate to Norway when the ice began to melt. That was more than 12,000 years ago. We believe that the char came from the west via the sea, and that it then swam up into our rivers and lakes. Then the char probably also came swimming through a large lake in the east. It was dammed by glaciers 8000-9000 years ago and is called Lake Ancylus.

Arctic char and stationary char

In Norway, we often distinguish between sea char and stationary char. They belong to the same species, but their names tell us how they live. From Nordfolda, located in the north of Trøndelag, and northwards, there are around 100 watercourses where char migrate into the sea. These char are called Arctic char. Those that will not or cannot migrate out, we call stationary char. Other nicknames for stationary char are freshwater char or inland char.

Arctic char can get heat stroke

The Arctic char is our second most common freshwater fish (trout is the most common.) It thrives best in cold water with lots of oxygen. In the south, it is therefore often found in deep lakes where the water is cold all summer long. In the north, it is colder. Here, many char live their entire lives in the river. Researchers have found that Arctic char can die from heat stroke when the water temperature is as low as 15-16 degrees Celsius. Arctic char can find food and eat in pitch darkness and in temperatures down to 0 degrees. This is an advantage in the darkness of the far north. We can rightly call the Arctic char a "cold fish"!

Røya would have gone on strike

Villaks og sjøørret fortrenger sjørøya i varme elver og varme, grunne innsjøer. Men sjørøya vinner der vannet er tilstrekkelig kaldt. Hva tror du vil skje med sjørøya nå når klimaet blir varmere?