Electrofish Monitoring on Northern River Catchments

Electrofishing is an effective annual fisheries survey method which is used to determine the densities of different juvenile fish species, focusing primarily on Atlantic salmon, which are endangered. 

To describe the process simply, an electrical current is put into the water which temporarily disables the fish so they are able to be easily collected with a net. The fish are then placed gently into a bucket containing an anaesthetic solution. Once they are under anaesthesia, they are carefully measured and a small scale sample is taken, this is then sent away to a lab to determine exactly how old the fish is. After hatching, juvenile salmon can remain in their natal river until they are up to 5 years old before beginning their first migration to the sea. Discovering how old each fish is in comparison to its size, can give us lots of important information such as how well the fish has been feeding, which is an indicator of how healthy the overall ecosystem is. 

When done properly, electrofishing causes no harm to the fish and is a valuable tool in determining how productive our river systems are. 

We are delighted to report that at almost all survey sites there appeared to be strong numbers of juvenile salmon around, which we are extremely relieved about given the notably hot and dry conditions we experienced earlier in the year. 

One of the scientists even said, referring to our Kinloch River “It doesn’t get any better than this”, considering the terrifyingly concerning reductions in salmon numbers that many other UK rivers, and beyond are facing, this statement is extremely reassuring for us to hear. 

We hope that this positive trend continues again next year. Meanwhile, we will continue to do our best to protect our fish and improve their freshwater habitats.