With financial support from the River Doon DSFB we commenced improvements on the Culroy Burn back in 2015. Several areas had been identified that suffered from accelerated erosion and severe nutrient inputs that the Trust staff considered solvable. We knew water quality and fish production were impacted. The silt load in this burn lead to the gravel being smothered and the habitat throughout was in less than good condition. Being a juvenile recruitment area rather than fishing beats, its was important to address these issues to overcome some of the challenges that salmon and sea trout face at the current time. This post demonstrates some progress we have made. Things will continue to improve with more time.
The Culroy Burn was traditionally a trout (brown and sea trout) burn but the DSFB had over many years stocked salmon. Neither species were naturally doing well by the time we started improvements despite this being a major tributary of the middle Doon catchment. The aim was to cut erosion and inputs and restore the quality of the habitat and thus production. After 9 years since we started, we were asked by the Board and have to ask ourselves, has this worked? Well the answer is yes and no. Erosion has been cut, water quality has improved, trout numbers have increased tremendously but salmon stocks remain very poor. Our opinion is that yes the work undertaken has achieved great benefits for fish and ecology however, with salmon survival at sea being desperately poor, few salmon are returning to repopulate this burn. Those that do, should have a much better chance of survival to smolt as they have clean water and good habitat once again.
Have a look through the photos below that show the condition of the burn in two key areas where we decided to install green engineering and then fencing to exclude livestock. Combined with this, we have planted trees that are beginning to provide shade and cover that will bring additional benefits as they mature.
We did have setbacks along the way with storm Abigail coming within days of us completing the work and destroying much of the work we had done. Never the less, we persevered and reinstalled the following spring and since then, there has been steady improvement. Some of the riparian trees we planted are doing well but others have been damaged by deer and hares. We will replant more and provide guards to help them become established.
Further upstream at Sauchrie, in early summer 2017 we also tackled severe erosion and nutrient inputs while at the same time removing a redundant weir. The change to this stretch of habitat is impressive and undoubtedly beneficial. Again, we could do more here and will continue to add trees to combat the losses of browsing mammals. But, the in stream habitat has changed dramatically with the burn narrowing and deepening. The cattle that once added nutrients and contributed to erosion have been excluded and water quality is now suitably good. Banks have rebuilt and stabilised as happens when the pressures are removed and we expect through time this stretch will become increasingly populated with fish (something lacking in 2017).
We have undertaken some assessment fo the fish population in this burn since we worked these areas and installed fencing. Trout numbers have increased tremendously and we hope will continue to do so. Salmon on the other hand have been slower to respond but that is more likely to be due to low numbers returning from sea rather than anything else and we know if they do spawn anywhere in the Culroy Burn in future, their survival should be much improved. Of course this was traditionally a trout rather than salmon habitat and that situation may prevail but any improvements done will benefit both species if they do choose to spawn here.
Additional benefits reported by by anglers and owners downstream is that water clarity as spates run off clears much quicker that previously and this is due to the reduction of fine silt and sediment produced in this burn. By making these improvements, we are giving salmon every chance to increase in numbers and their range within the Doon catchment and we are grateful to the Doon DSFB for their proactive support for this type of work. This is exactly what we believe river managers can and should do to help salmon survive at this worrying time when their marine survival is so poor.
Good work a.r.t. habitat improvements are badly needed on most ayrshire burns and tributarys. Sadly most clubs and anglers not interested in doing habitat improvements….