Wild Harris

Atlantic Salmon

Salmon are found all over Harris in our rivers, lochs and burns.  They are born in our rivers and then they head out to feast and mature at sea before returning home to freshwaters to breed.

Salmon use their brilliant sense of smell to find their way right back to the same river and even the same spot in the river, where they were born. They are famously stron swimmers and can even jump tall waterfalls. A good place to see salmon leaping is the waterfall at Amhuinnsuidhe in North Harris.

atlanticsalmon10d L.Campbell.jpgAtlantic Salmon, Adult Male    (Photo: Laurie Campbell)

Special features

Salmon have strong tails and use them to flick stones on river beds to make a pebble nest called a redd. These strong tails also help salmon to shoot up waterfalls that can be four times higher than them.

Male salmon turn bright colours and fight to impress the females. They have big bottom jaws shaped like a hook that they use to grab each other.

atlantic salmon 4540 L.Campbell.jpgAtlantic Salmon, Adult Male    (Photo: Laurie Campbell)

Most salmon use all of their energy to make young and die quickly after they have released their eggs.

Life cycle and habitat

Most salmon move between freshwaters where they have their young and grow up, and the sea where adults go to fatten up. Small numbers of male salmon decide not to go to sea and stay in freshwaters for their whole lives. These salmon never grow very big but can find a female mate when bigger salmon are busy fighting!

Life in freshwaters

Adult salmon in bright silver livery arrive around our coasts from early spring with the peak in arrivals occuring in high summer. They should be fat from rich feeding on the high seas around Greenland and Iceland over the past year or more.  Most will never feed again and all of them will fast until after spawning.  Luckily this does not stop them from snapping at fishermen’s lures!

When river levels are high during summer spates they swim upstream, heading towards the place where they were born.

atlantic salmon 1943 L.Campbell_1943436748.jpgFresh Run Atlantic Salmon    (Photo: Laurie Campbell)

By the time the spawning season starts in early December, the Male salmon have changed livery.  They turn very red and develop a hook shaped bottom jaw called a kype. The male salmon battle for the right to pair with the females and breed.  Together a male and female salmon use their strong tails to move stones and make a rocky nest called a redd.

atlantic salmon 4967 L.Campbell.jpgPair of Atlantic Salmon on Redd  (Photo: Laurie Campbell)

During spawning, the Females lay hundreds of eggs which are orange and pea sized.

atlantic salmon 8016 L.Campbell.jpgAtlantic Salmon Eggs    (Photo: Laurie Campbell)

The male then immediately fertilizes the eggs with his milt. After spawning the parents cover their eggs with some gravel to stop them from washing away and to hide them from predators.

Most adult salmon have used up their energy and die after spawning. This is why you can see dead salmon on river banks in the winter. Sometimes dead salmon have bite marks where otters have had a munch. A few salmon (about 5 in every 100) are strong enough to stay alive and these go back to sea in the spring, these salmon are called kelts.

Salmon eggs stay in the gravel until spring when little salmon called alevins hatch out. Alevins have a yolk sack. This means that they do not need to find any food to eat and can stay hidden in the gravel for six weeks.

When their yolk runs out alevins leave the gravel. Now they look like small fish and are called fry. The fry feed on insects, worms and other small animals. Their fins are strong and they can swim well. Fry are dark coloured so that they cannot be seen by trout, big salmon and herons. Any of these would like to eat the little fry.

As they grow fry change colour and after about a year they get dark stripes on their sides and bright red spots. Now they are as big as your hand (8cm) and called parr. Because our waters are cold, parr stay in our streams for two, three or four years but in warmer places like Spain, parr grow fast and can go to sea after just one year.

Atlantic_salmon_parr.jpgAtlantic Salmon Parr    (Photo: Wikimedia)

Fry and parr like to live in rivers and burns with lots of places to hide like under boulders and water plants. They also like places where the river banks have lots of plants and trees. Water insects come to eat the leaves and then salmon eat the water insects!

800px-Salmo_salar_smolts.jpgAltlantic Salmon Smolts    (Photo: Wikimedia)

Before they go to sea salmon take on a lovely silver colour and are called smolts. The silver colour matches sparkling sea water and helps smolts to hide from big sea creatures that would like to eat them. Sea birds such as gannets and big fish like lythe (pollock) and porpoise all like to eat tasty smolts. As they swim towards the sea smolts are careful to remember the smell of their river so they can find their way back when they are grown up.

Life at sea

At sea salmon eat shrimps and small fish like sand eels and herring, these foods are full of fat and make the salmon grow quickly. Salmon stay together in groups and swim very long distances to find the best food. Salmon from Harris can travel thousands of miles, all the way to the water around Greenland, but some stay closer to home feeding near to the Faroe Islands.

Atlantic Salmon at Sea.jpgAltlantic Salmon Smolts    (Photo: Wikimedia)

Some salmon spend four years at sea and grow very big before they come back to Harris rivers; others come back after just one year. No matter how long salmon wait before coming home they must be careful, seals, otters, herons, dolphins, sea eagles and humans are all waiting to catch them!

The importance of Atlantic Salmon to Harris

The wildlife of Harris, including humans needs salmon!

Salmon are challenging and exciting to catch.  They are also excellent to eat.  Salmon are the most sought after sport fish, attracting locals and lots of visiting anglers to Harris supporting many local businesses.

Because they are cold and clean our rivers do not have much food in them for fish and water bugs. When salmon come back from sea and eventually die their decaying remains release nutrients into the spawning burns.

Salmon are having a tough time. When they go to sea lots of young salmon die so less and less are returning to our rivers. There are lots of reasons for this. We think one of the most important reasons is that the sea is heating up causing the fish and shrimps that salmon eat move away. Salmon do not have televisions or newspapers so they don’t know that their food has moved and go back to the same old eating places. When there is no food in those places we think many young salmon starve.

Another problem can be fish farms. Some fish farms have lots of sea lice, these are a bit like fleas and they jump onto wild smolts when they are swimming out to sea for the first time. Sea lice are not a problem for adult salmon but if lots of sea lice attack a salmon smolt they can kill it.

So in Harris we are working hard to protect salmon. People are planting trees by river banks to make sure there are lots of insects for salmon to eat, fish farmers are trying to keep sea lice away from their farms and salmon anglers do not keep all of the salmon they catch, they put most back into the water. We hope that by looking after the salmon we will make sure that this amazing fish keeps coming back to our clean, clear freshwaters.

Links

Salmon Life Cycle- http://www.snh.org.uk/Salmonintheclassroom/salmon_lifecycle.shtml

http://www.atlanticsalmontrust.org

http://www.fishpal.com/Scotland/Hebrides

http://www.snh.org.uk/Salmonintheclassroom

by Katherine Ross