Alastair Stephen, SSE Fisheries Biologist, has worked with SSE for nearly two decades. In that time he has made it his business to keep a close eye on the fish that pass through our hydro scheme. With this year’s fish tagging now complete we’ve asked him to describe why the environmental work our hydro team does is so important.
If you speak to anyone in SSE’s hydro team you may be surprised to find out that producing electricity isn’t the only important aspect of our jobs. It is important we minimise the impact our hydro stations have on the local environment, especially salmon, so managing water levels and the environment is all part of producing power from water sustainably.
Managing the environment has involved SSE collecting data on fish movement for decades. To help us make informed decisions we work closely with fisheries boards throughout Scotland to track infant salmon, known as smolts, as they leave Scottish rivers and make their way out to the Atlantic Ocean and North Sea.
Working with the local fisheries boards is crucial. The rivers and its inhabitants are just as important to them as they are to us so working together definitely makes collecting the data easier.
As technology has evolved, so has our ability to track fish movements. We are now able to tag smolts using Passive Integrated Transponders (PIT) as they pass through our stations so when they return as adult salmon we have an idea of the numbers that come back. The technology is very similar to that used to tag a dog or cat.
I recently worked with Simon Mckelvey of the Cromarty Firth District Salmon Fishery Board on this year’s fish tagging. The process involves catching the fish in a purpose build permanent smolt trap or by using a mobile device in the river called a Rotary Screw Trap. We then measure them, weigh them and insert a small tag into the smolt’s underside (which heals within hours and doesn’t have any long term effect on the fish).
The process requires a lot of work, but doesn’t damage the fish and the data we get is invaluable. We can use the information to adjust our hydro operations and share the data with all interested parties so we can understand more about the salmon’s travel patterns.