Doonbeg Salmon Conservation Project
Finnian from Hometree helping with the tree planting.
Inland Fisheries Ireland are the environmental agency responsible for protecting, managing and conserving Irelands inland fisheries and sea angling resources. Inland Fisheries Ireland also provides funding to various eligible organisations to carry out Conservation and Development projects. Since 2016, over €8 million worth of funding has been awarded to over 300 Conservation and Development projects by Inland Fisheries Ireland.
Jonathan Coates-Farrell, the Assistant Inspector for Clare, writes about Doonbeg Salmon Conservation Project and their collaboration with Hometree. After learning of the rising temperatures in the Doonbeg, Jonathan applied for funding to carry out the Riparian planting project and will continue to apply for funding each year to carry out further planting in an attempt to mitigate the effects of climate change, improve habitat and protect the Salmon and Sea Trout populations in the Doonbeg.
The Doonbeg is a Westerly flowing spate river that drains into the Atlantic on the West Coast of County Clare at Doonbeg village. It is a salmonid river that supports good runs of Atlantic Salmon (Salmo Salar) and Sea Trout (Salmo Trutta) and is currently the only river in Clare open to Salmon and Sea Trout fishing, on a catch and release basis.
Inland Fisheries Ireland (IFI) have identified climate change as one of the greatest threats to the future of aquatic ecosystems (Barry et al, 2022). In preparation of the threat, IFI established the Climate Change Mitigation Research Programme (CCMRP) to gather evidence, assess the current situation and predict future effects to Irish fisheries. The project recorded temperatures throughout the Doonbeg river catchment and results have shown that between July 2020 and August 2021, the number of days that the average mean daily water temperature exceeded 20 degrees Celsius, ranged from 9-18 (Barry et al, 2022).
Salmonids require water temperatures between 5-15 degrees Celsius for normal growth (Elliot and Elliot 2010). Temperatures above 22 degrees Celsius for a period of more than seven consecutive days can be fatal (Elliot and Elliot 2010). The data gathered from the CCMRP has shown that in the lower half of the Doonbeg catchment, potentially fatal conditions occurred across numerous sites. With the change in climate forecast to continue in an upward trend of higher summer temperatures, these results and the risk to Salmonids are likely to increase (Elliot & Elliot, 2010 & Garner et al, 2013).
To help mitigate the rise in water temperatures, it is recommended that riparian tree planting can provide shade to a river and help lower the temperature if done correctly and for an adequate distance of the bank according to width and flow rate of the water (Bowler et al, 2012; Broadmeadow et al, 2010; Caissie, 2006 ; Correll, D.L. 2005 & Johnson and Wilbey, 2015). IFI identified a stretch of river that has little riparian cover upstream of a CCMRP temperature monitor. Using recommended formula (Johnson and Wilbey, 2015), 1.6km of this stretch would need to be shaded to help reduce temperature by 2-3 Celsius (summer mean max) (Bowler et al, 2012 & Caissie 2006).
With the landowners permission, IFI have planted a riparian buffer zone with an assortment of native trees, sourced locally and of local provenance, along the southern bank of the chosen stretch of river. The southerly bank will soon be better shaded against sunlight during the summer months. Following recommended guidelines (Broadmeadow et al, 2010 & Johnson and Wilbey, 2015), the planted saplings were spaced two meters apart and be planted in a staggered system along a two meter wide riparian zone on the southern bank of the river. There will be single wire electric fencing protecting the strip as some of the land is currently grazed by cattle.
Results will be monitored via the temperature monitors and the CCMRP each year compared with other unshaded sites close by of similar dimensions. If the project is successful, there will be a reduction in water temperatures for that location and a reduction in temperature at sites downstream thanks to the cooled water. Going forward, further sites will be selected and riparian planting replicated with the intention of reducing the effects of climate change and safeguarding the ecological health of the river.
Additional benefits of having a planted riparian zone are:
Improved habitat – Increased habitat diversity both terrestrial and underwater.
Shade and shelter – Shade from direct sunlight and also shelter from predators.
Nutrients – Leaves and woody debris provide nutrients to support the food web.
Bank stabilisation – The root system formed throughout succession hold the soils together.
Flood prevention – riparian zones increase the holding capacity of the soils which can moderate flooding.
References
Barry, J., Coyne, J., Kelly. S., and Kelly, F.L. (2022). Climate Change Mitigation Research Programme, Annual Report 2021. National Research Survey Programme, Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin 24. P. 6
Bowler, D.E., Mant, R., Orr, H., D.M., Pullin, A.S. (2012). What are the effects of wooded riparian zones on stream temperature? Environmental evidence 2012, 1:3.
Broadmeadow, S.B., Jones, J.G., Langford, T.E.L., Shaw, P.J. and Nisbet, T.R. (2010). The influence of riparian shade on lowland stream water temperatures in southern England and their viability for Brown Trout. River Research and Applications DOI: 10.1002/rra.1354
Caissie, D. (2006). The thermal regime of rivers: a review. Freshwater Biology 51, 1389-1406.
Correll, D.L. (2005). Principles of planning and establishment of buffer zones. Ecological Engineering. Vol. 5., pp 433-439.
Elliot, J.M. & Elliot, J.A. (2010). Temperature requirements of Atlantic Salmon salmo salar, Brown Trout salmo trutta and Arctic Charr salvelinus alpinus: Predicting the effects of climate change. Journal of Fish Biology (2010) 77, 1793-1817.
Garner, G., Hannah, D.M., Sadler, J.P. and Orr, H.G. (2013). River temperature regimes of England and Wales: Spatial patterns, inter-annual variability and climatic sensitivity. Hydrological Processes Accepted manuscript online: Accessed 12/01/23
Johnson, M.F. and Wilbey, R.L. (2015). Seeing the landscape for the trees: Metrics to guide riparian shade management in river catchments. Water Resources Research 50: 3754 – 3769.
