Each winter a wildlife spectacle unfolds in my local Sussex countryside that remains largely unknown and unseen. The sea trout, the ocean going form of our native brown trout (and exactly the same Salmo trutta species), returns to freshwater rivers just as salmon do, to pair up and lay their eggs in gravel stretches high up in the feeder streams where the water runs cleaner and faster and holds more oxygen.

While in the sea they are bright silver with larger dark spots than their cousin the Atlantic salmon, but as they enter freshwater and spend time in the river on their way upstream, they turn a range of russet reds and browns which is their spawning livery. They face many obstacles on their journey up the rivers, notably from old weirs constructed in a time when conservation was not a term often used and migration of fish up and down rivers was little understood. Thankfully there are projects underway and work already undertaken to either remove weirs or to provide a means of easy passage such as fish ladders to go around them. 

The South Coast Sea Trout Project (SCSTP) is partnership between the Environment Agency, the Wild Trout Trust and the Atlantic Salmon Trust, with local Rivers Trusts providing a crucial element of local support and funding.

For example the Ouse and Adur Rivers Trust runs a Sea Trout Watch program each winter that you can volunteer for which finds and records the locations of sea trout spawning areas across the catchment to help with ongoing research and management of those areas. 

I was lucky enough to come across a few spawning pairs this past winter and got the chance to record some video on my iPhone which you can see above. If you watch closely you will also see first 1 and then 2 (right at the end) little trout hanging around the larger spawning pair hoping to get a free meal of any food items dislodged from the gravel or even an egg or two if they are lucky.