In the next few weeks thousands of young salmon will be making their hazardous journey down rivers and out to sea in their annual spring migration. But how many will return to their natal rivers in the next 3-4 years in order to spawn and produce the next generation? With wild salmon stocks in steep decline, scientists from the Game & Wildlife Conservation Trust will use advanced monitoring technology on the River Frome in Dorset as part of an international effort to save the species.
According to recent figures, anglers participating in freshwater salmon fishing inject a staggering £500 million into the rural economy, but this important source of income could be under threat because of the serious decline of Atlantic salmon populations.
Globally, Atlantic salmon have suffered a massive 70 per cent decline in the past 30 years and there is now an international effort in place to provide effective conservation and restoration of the species.
In this country, one of the leading centres for wild salmon and sea trout research is on the River Frome in Dorset is now managed by The Game & Wildlife Conservation Trust. Until recently, the fisheries research based on the river was run by the Centre for Ecology & Hydrology.
The Game & Wildlife Conservation Trust’s salmon and trout research centre at East Stoke, is directly involved in the international effort to research wild salmon declines and their causes and the entire river catchment has been transformed into an impressive natural river laboratory. To date, this research facility, which comprises the most technically advanced scientific monitoring equipment of any river in the country has collected nearly 40 years of data, which will have an important input in the future management of adult salmon.
Dr Nick Sotherton, director of research with the Game & Wildlife Conservation Trust said, "The number of fish returning to rivers from the sea is falling, but there are also problems in the river. High sediment loads reduce egg survival and predators take the young fish. Although these hazards for salmon have always existed, their effect is more noticeable given the low numbers of adults returning from the sea."
Dr Anton Ibbotson who will head the Game & Wildlife Conservation Trust’s research centre at East Stoke, said, "Over the last ten years we have developed specialist techniques for tagging individual fish to work alongside state-of-the-art fish counting, monitoring and tag detection equipment installed on the River Frome.
"We have individually tagged 50,000 salmon parr in the last four years, which could now be distributed anywhere between the River Frome and the icy waters of Greenland. Once they start returning to the river over the next few years we will be able to monitor their arrival and help build up a picture of why some fish have survived in the sea and why others have not. This will help manage salmon populations in the future."
A unique feature of the catchment-based laboratory is the ‘hands off’ automatic electronic smolt counter which counts the delicate juvenile salmon and sea trout as they migrate to sea. The use of Passive Integrated Transmitter (PIT) tag technology enables the scientists to study large numbers of individual fish in order to better understand the factors that influence the life history, survival and migratory patterns of both salmon and sea trout. This facility is not replicated anywhere else in the UK and has far less damaging affect on the fish than using traps or other interception devices.
Dr Ibbotson explains the implications of this research, "This natural laboratory will enable us to answer many of the really important questions about salmon and sea trout stocks that would be difficult to answer elsewhere. A really good example of this is how the environmental conditions the fish experience in freshwater affects their survival in the sea. Too often, we see marine and freshwater sources of mortality as independent, but now we can follow large numbers of individual fish from their early freshwater life -stages through to maturation and spawning."
Dr Nick Sotherton, the Trust’s director of research, said, "This is one of the best equipped rivers for salmon and sea trout research in Europe and the research is relevant to every salmon fisherman in the country, whether he or she fishes the Spey or the Test. Working on this influential research laboratory, which has international and national standing is a considerable boost to our existing brown trout research programme and we believe it will have dramatic implications for international salmon research."
To support this important project the Trust has secured start-up funding from a wide cross section of organisations including the Garfield Weston Foundation, The Valentine Trust and the Alice Ellen Cooper-Dean Trust as well as the Atlantic Salmon Trust and the Salmon & Trout Association. The Trust is also grateful to the Centre for Ecology & Hydrology (CEH) and the Freshwater Biological Association (who own the site) for their help and support in getting this project off the ground.
Mrs Teresa Dent, The Trust’s Chief Executive said, "As a wildlife conservation charity specialising in game species, taking over this facility has given us a fantastic opportunity to get involved in cutting-edge research to help the recovery of Atlantic salmon. Many of our members and supporters are passionate about this fascinating species and we hope that they will support our current fund raising-appeal for this ground-breaking research."
Ivor Llewelyn, Deputy Director (England and Wales) of the Atlantic Salmon Trust, said, "The Atlantic Salmon Trust is delighted that the GCWT is taking on responsibility for the work of the river laboratory at East Stoke. For many years the laboratory has provided valuable insights into salmon behaviour and survival, and we are pleased that this important contribution to salmon conservation will continue."
