A river runs through it
Ever since the advent of hydro power to Scotland, SSE has been required to protect the fish in the waters where the company operates. The very Act of Parliament which established our company in 1943 stated: ‘The Board should have regard to avoiding as far as possible, injury to fisheries and to the stock of fish in any waters.’
And 73 years later that remains the guiding philosophy. It is why SSE is investing in a new salmon hatchery building at Contin, north of Inverness - capable of housing some three million fertilised salmon eggs at any one time.
Ahead of the new building’s official opening on December 14th we spent a day observing how, in close partnership with the Cromarty Fisheries Board, salmon are helped through our dams on the Conon River system.
“Central to the success of this hatchery scheme is the close working relationship we have with the Cromarty Firth Fishery Board,” explains SSE’s Marine Biologist Alastair Stephen.
“We have a legal and I would say moral obligation to look after the salmon here as their natural spawning grounds were affected by dams we put in the 1950s. Salmon are an iconic part of the Scottish wildlife and also bring in huge socio and economic benefits to the area.
“That’s why SSE is investing so heavily in the new hatchery building which has been here since 1958 but was getting past its sell-by date. But a hatchery system is not a one size fits all solution. Yes, we can get between 1,000-1,500 salmon each year upstream to spawn successfully in this way, but elsewhere you should always let nature take its course.”
This hatchery scheme is unique to the heavily hydrolysed area of the Highlands where our network of dams means salmon can’t reach their native spawning grounds without help.
So the idea is to lend Mother Nature a helping hand by fertilising the salmon eggs and sperm before storing them in the hatchery building. The fertilised eggs are eventually released upstream of any obstacles in gravel beds in the spring.
Stage one of the process involves the salmon team wading into the river and into the Blackwater salmon trap at Loch na Croic, which looks like a giant lobster pot. The fish are then caught by hand and the team shout out if the fish are male (cock) or female (hen).
The caught salmon are then rushed into a holding facility in bags before the stage two. The egg ‘stripping process’ begins, which involves anaesthetising the fish (gas and air for salmon you might say) and carefully squeezing the eggs from female fish into a dry bowl.
Sperm from male fish is then added to fertilise the eggs before they are washed and prepared for transport to the new hatchery building where they will be incubated over the winter. In the spring the eggs will be carefully buried in river gravel beds with the idea being at all times to mimic the natural salmon lifecycles as closely as possible.
The parent fish which have done the spawning are allowed to recover from the anaesthetic before they swim away none the worse for their experience upstream of the trap.
Stage three takes place inside the new hatchery building and involves the collected eggs and sperm mixture being carefully poured into trays where they will be kept safely over the winter.
Holding an original pint jug measure (3,500 eggs per pint) used back in 1958 is Simon McKelvey from the Cromarty Fisheries Board. “These are the first fertilised eggs to be stored in the new hatchery building,” he explains. “So it’s a small moment of history.
“At all times we endeavour to mimic nature so they will be released as fry or eggs so they remain wild and are exposed to natural selection. Although the process of stripping the eggs can look uncomfortable it’s actually less stressful for the female salmon that nearly always damages her tail making gravel beds for the eggs to spawn in. The fertilised eggs and the salmon that have spawned them have a higher survival rate this way.”
And with that the new hatchery building is well and truly christened with the prospect of helping many future generations of salmon to successfully spawn in this way.