“Signs are positive” as River Frome sees highest salmon numbers in eight years, but climate change is having an impact says new report

Following successive years of decline in adult salmon on the River Frome, numbers of young salmon leaving the river in 2020 to go to sea were 40% up on the 10-year average, according to the latest figures in a fisheries report launched today. An estimated 13,062 salmon smolts left the River Frome, the highest number of emigrating smolts recorded since 2013.

The annual Fisheries Research Review, published this week by the Game & Wildlife Conservation Trust (GWCT), shows signs of hope for the long-term future of salmon in Dorset’s River Frome. Time will tell how many of these fish return to the river from the North Atlantic in 2021 and 2022, but experts say signs are as positive as they have been for some time.

“As well as the high number of smolts (young salmon leaving the river for their marine journey) leaving the river, it’s encouraging that they were larger than average too, making them better equiped for life at sea,” says Rasmus Lauridsen, Head of GWCT Fisheries Research.

Previous research by the GWCT has shown that larger smolts are more than three times more likely to return from the sea than smaller ones, so it is hoped that the adult salmon passing through their Wareham-based monitoring station on their return will be higher than in recent years when they are back from the Atlantic this summer or next.

“The past three years have seen below-average numbers of adult salmon returning to the Frome,” adds Rasmus, “although our monitoring in 2020 showed a surprisingly good number of the smolts leaving in 2018 returning, having spent two years at sea.”

It isn’t all good news for our much-loved salmon, however. Further research has shown a combination of warm winters and cool springs negatively impact the recruitment of juvenile salmon in the predominantly groundwater-fed River Frome. This builds on previous GWCT research on the predominantly rainwater-fed rivers of Wales where we found similarly impacts of temperature, highlighting how similar freshwater conditions in contrasting river-types can significantly affect population dynamics.

These insights will be pivotal in planning future conservation measures, with the GWCT one of the founder members of the Missing Salmon Alliance, a group of organisations fighting to reverse the devastating collapse in wild Atlantic salmon around the UK. By combining expertise and data, coordinating activities and advocating effective management solutions they aim to help wild Atlantic salmon survive and thrive in our rivers and seas for future generations.

The review can be downloaded for free at www.gwct.org.uk/fisheriesreport