Smoltification – that’s the name of the game!

We thought we’d share this video with you. How stunning are these little beauties? Not much longer than your finger (assuming you’ve got big man’s hands like me). This is a gathering of Smolts. Having spent several years in the River as Parr, they are now getting ready for the next stage in their incredible journey. We all know that Salmon are incredible travellers and much has been filmed, written and said about their upstream migration as adults, as they return to their natal water to spawn and begin the cycle all over again, but this journey is just as amazing in its own way. While they’re not fighting gravity as their parents did, the heroics are still going on, just in a more subtle way. About now, during the Spring they start to change. Not just in appearance.

They lose the colour in their flanks and become more silvery; this is an adaptation to life in the ocean’s surface water – they will blend in better in the light and sparkling conditions. Accompanying this is a change in physiology and behaviour. Their coming together as a shoal is part of this. The process is called Smoltification (that’s your word of the day!)

This is happening right now largely unseen except in places like this leat. We filmed these fish in the clear, shallow waters of a leat on the edge of Dartmoor, not far from Chagford. They have accidentally been side-lined from the main river into a leat that supplies a private Hydro Electric Plant. Frequenting the thin waters of the leat, while making them easy to observe (and film) for us – also makes them easy to see by predators. While I was filming these fish, I was all the while under the watchful eye of the local Grey Heron. There is also the possibility that these fish may become trapped or detained in these artificial watercourses, delaying them at a critical time in their life-cycle.

The good news was that a day after this footage was taken (on May the 7th) we had some heavy rain and with the accompanying rise in the water – most of the fish had moved on their way.

I know what you’re asking… which is which? How do you tell a Salmon from a Sea Trout Smolt? I’ll get back to you on that…. for now, enjoy a rarely seen splash of spring colour and a spectacle that says ‘spring is here’ as clearly as any wood full of Bluebells or a male cuckoos call.

Nick Baker (River Teign Restoration Project Officer)

The etymology of the word Smolt probably comes from middle English smylt or smeolt. Which means “mild, peaceful, serene, still, gentle, clear, bright”. The word smelt (which similarly means bright, shining and smooth) shares an origin here. Watching these fish dance and dazzle in the spring sunshine, it all starts to make sense – doesn’t it?

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