Arctic charr were here before trout and salmon. They were the first fish to return to our freshwaters after the last Ice Age. As their name suggests they like cold water and are found in deep lochs such as Loch Langabhat in North Harris.
Loch Langavat (Photo: Virtual Hebrides)
Scottish Arctic charr were once migratory and used to go to sea like salmon and sea trout, but all of our charr populations are now non-migratory and remain in freshwaters throughout their lives.
Charr are beautiful fish and males have bright red or orange bellies to attract females.
Artic Charr (Male above)
Charr make gravelly nests like trout and salmon.
Charr can only live in cold water and are being lost from England as climate change heats up the lakes there.
Life cycle and adaptations
Charr came to Scotland from waters near to the Arctic following the last ice age. They eat small animals such as pea mussels and worms and sometimes fish.
Charr are related to salmon and trout and make similar gravelly nests for their eggs. These nests are called redds. Redds are made along the shores of lochs or in shallow burns. Charr spawn (mate) in the summer and at this time males have bright red or orange bellies to attract females.
Charr populations such as those in Loch Langabhat may have been on their own (isolated) for over ten thousand years. During this time they have developed special adaptations to suit this loch. Some of the charr feed on small animals on the loch bottom while others come to the surface at night to feed on swimming bugs (zooplankton) and small fish. Although they are the same type of fish these two forms of charr probably do not mix. They spawn at different times or in different places.
The importance of charr to Harris
Charr are important food for ferox trout (trout that specialise in eating fish). Charr are sometimes fished because they are unusual and delicious!
Charr have been lost from many lochs and rivers in England, Ireland and southern Scotland. As their name suggests charr originated close to the cold Arctic and cannot survive for long periods in water temperatures above 15oC. Our cool waters make the Outer Hebrides one place where charr can remain even as climate changes makes freshwaters heat up.
As well as climate change humans have killed charr by altering rivers and lochs so that water levels drop and charr eggs dry out (this happens where we dam lochs to use the water for drinking or making electricity), polluting their streams with chemicals or sewage and putting new types of animals into lochs that like to eat charr. So it is important that we look after charr on Harris.
By Katherine Ross