DEE BEAT by JOANNA DICK Dee catchment Outreach Officer

A leaping salmon.
A leaping salmon.

The Atlantic salmon or ‘King of Fish’ is both the largest and best known fish that lives in Scotland’s rivers.

It has a long relationship with humans and is an extremely important contributor to rural economies, but it also plays an important part in the overall ecology of our rivers.

Atlantic salmon dominate the fish community of the River Dee and represent 95 per cent of fish found in the River. Anglers have fished the River Dee for salmon since the 17th century, and today angling on Deeside contributes £16 million to the local economy and supports 500 jobs.

But other species of fish thrive in the Dee – and some were around before the dinosaurs!

Brown trout are found throughout the Dee catchment, particularly in smaller tributaries with good water quality and a moderate flow, but the River Dee is not as well known as other nearby rivers (the Don, for example) for brown trout.

This may be due to lower levels of nutrients in the Dee catchment, which encourages more of the trout to migrate to sea.

Sea trout and brown trout are the same species and are distinguished by their different life styles: sea trout move down into coastal waters after typically spending two to three years in freshwater, while brown trout remain in the river.

Most sea trout do not migrate far out to sea but spend the majority of their time close to the coastline.

Eels are present throughout the Dee, but are locally absent in areas where water quality is poor.

The migration of eels from European rivers to the Sargasso Sea, south-west of Bermuda, is one of the most impressive examples of animal migration.

Eels undertake a similar journey to salmon but in reverse; eels leave the river and go to sea to spawn whereas salmon return to the river to spawn.

In recent years, there has been a 95 per cent decline in eel numbers, most likely due to human impacts such as man-made obstructions in rivers and climate change affecting their marine survival.

Similar to eels in appearance are lampreys, with a long cylinder body, large eyes and silvery skin.

Lampreys have been around a long time as fossil remains show they existed long before the dinosaurs! There are three species of lamprey, named after where they live – sea, river and brook – and all three are found in the Dee.

Lampreys have very distinct features that haven’t changed much during their long existence.

Firstly, the lack of a jaw; instead they have a large flexible lip and circular sucker that contains rasping teeth used to attach themselves to a host fish such as salmon and feed off the living tissue. Lamprey do not have bones, instead they have a strong flexible skeleton made of cartilage. Nor do they have gills, instead a series of seven sac-like gills that open directly through holes on each side of the head.

The presence of minnows in the River Dee is entirely due to introduction by anglers for live bait.

Whilst this practice has now been outlawed, minnows have colonised the majority of the River except the very upper reaches.

A small population of minnow is present in the upper catchment of the River Gairn, released by anglers fishing Loch Builg, in the Spey catchment, for trout and Arctic charr.

The flounder, a marine flatfish, is found at the mouth of the River Dee. It is one of few saltwater fish able to survive for long periods in freshwater, and regularly spends its juvenile stage in freshwater after hatching in the sea.

Flounders have been captured in electric fishing surveys in the lower parts of the Dee as far upstream as Tilbouries, around 20km from the sea.

Other fish found in the Dee include pike that mostly reside in Loch Kinord, Loch Davan and Loch Callater and three-spined stickleback.

River Dee Water-Based

Users Information Evening, April 29

We are holding an information evening to discuss the River Dee Paddler and Angler Guidance and use of Loch of Skene for non-motorised watersports (review of users’ experiences) next Tuesday at 7pm in Adventure Aberdeen, Fairley Road, Kingswells, AB15 8PZ.

If you would like to attend the event, please email or telephone 01339 880 411.

The Dee Catchment Outreach Officer is funded by Aberdeenshire Council, Aberdeen City Council, Aberdeen Harbour Board, Cairngorms National Park Authority, Forestry Commission Scotland, MacRobert Trust, Marr Area Committee, River Dee Trust and Scottish Natural Heritage.