'Tis the season to be spawning

Wildlife Diary

Jodie Simmons

Jodie Simmons

Data, Evidence & Communications Officer

We are at the time of year where Salmon and Trout will be battling their way up river to spawn. As part of their fascinating life cycle, these migratory fish return year after year to the same spawning grounds to lay their eggs. Salmon and Trout usually spawn on a riffle or the end of a pooled section, with loose gravel and shallow fast flowing waters. Spawning grounds are usually found higher up in a river but can be found anywhere above the tidal limit.

Find out how the Westcountry Rivers Trust are protecting Wildlife...

Once you get your eye in, it is possible to spot where a female or ‘hen’ has laid her eggs. Female fish use their tail to dig a nest in which she will lay her eggs, she then recovers the eggs with gravel. So, if you see a large fish frantically skittering across the river bed, chances are she is building a nest for her offspring. Although these nests can be over 20cm deep they are very delicate in construction. Therefore, if you see any clean looking patches of gravel in the river bed it is advised that you stay out of the river and keep your dogs on the river bank, as any type of disturbance can kill all the eggs present.

This unique spawning behaviour in one of the reasons we work to keep our rivers clean and free from barriers. At this time of year more than ever, it is crucial that spawning grounds are kept clean and free from sediment, as more sediment makes it harder for the fish to burrow as well as starving the eggs of oxygen. By working with land users in projects such as Upstream thinking, we are preventing sediment being washed into the rivers, we are preventing these valuable spawning grounds from getting clogged up. We can also add clean gravel to the rivers to create new spawning grounds in affected areas.

So when you are out walking this Christmas remember, it may not look like there is much around, but beneath those barren looking gravels the next generation of Salmon and Trout is stirring….