Position of Salmonids in the Carbon Cycle of a Peatland Lake Ecosystem

Salmon and sea trout are keystone species in aquatic habitats in peatland catchments, occupying the top of the food chain. Peatland catchments are an important feature along the Atlantic coasts of Scotland and Ireland, and are highly sensitive to the effects of climate change. Peat covers only 3% of the world’s land surface area but hold 30% of its soil carbon. Climate change is highly likely to lead to substantial carbon losses from peat, which will raise the dissolved carbon levels in peatland lakes and rivers, which may in turn threaten the survival of salmonids in these waters. However, the relationship between salmonids and their environment is a complex one, and they themselves play a role in the carbon cycle. The Marine Institute’s Salmon Research Agency at Furnace in Co. Mayo, Ireland, is planning a research programme to explore these issues.


This one year pilot project will contribute to this by testing the use of stable isotope analysis to determine what proportion of the diet of lake dwelling salmonids is derived from terrestrial sources. a key question if the impact of changes to carbon levels on salmonids is to be assessed. The project was revised on the advice of the AST to widen the range of samples tested. The Marine Institute met the costs of sampling, with the AST paying for the costs of analysis. Sampling was conducted in October 2015, and analysis was carried out by the Colorado Plateau Stable Isotope Laboratory in the first half of 2016. Initial examination of the results indicates that the analyses were successful, and  valid stable isotope signatures for  lake dwelling 0+ and 1+ salmon and trout were  obtained. More detailed analysis will follow in the second half of 2016.

While this project falls with the Trust’s Sea Trout research programme, it is of equal relevance to salmon.

Partners: Marine Institute, Ireland; Atlantic Salmon Trust

AST Funding 2105/16: £2,000