As part of a team comprising the Tweed Foundation, Forth Rivers Trust and Glasgow University, we are undertaking a study into the response of the fish community to restoration measures implemented by the Tweed Forum on the Eddleston Water in the Scottish Borders. To date the project has involved a baseline fish habitat walkover which was combined with historic data and power analyses to establish a three-year monitoring programme; two years of monitoring within the Eddleston main stem; and two years’ monitoring in two Eddleston tributaries. It is hoped that the findings of this study, due to continue until 2020, will feed into the knowledge base supporting links between river restoration and recovery and improvement of fish populations.
Trex Ecology were contracted by JBA Consulting to design and implement a study into the response of salmon and trout populations to cooling water discharge in two Spey tributaries. The project, which is being delivered with the assistance of the Spey Foundation, has to date surveyed 10 sites which have been combined with an historical data assessment of almost 40 sites to highlight differences in density and growth in impacted and non-impacted sites. Surveys are due to continue in 2019, after which the final report will be presented.
Following award of a planning permission, Trex Ecology were contracted to discharge planning conditions related to lamprey and invertebrate communities in Longford, Ireland. This project involved surveying numerous sites over several days to assess the potential for the works to impact on the presence of lamprey species, and also to assess general water quality in channel adjacent to the site.
Working with several clients, we have recently surveyed a large Scottish river for freshwater pearl mussels where works are planned. Using standard wading assessment and snorkel-based methods, data collected during these surveys identified the presence of at-risk mussels. This information was then used to ensure adequate mitigations would be in place for the planning application process.
Trex were asked by MannPower Hydro to review regulatory feedback regarding the proposed hydroscheme on the Teviot at Hawick. Following a site survey and habitat assessment, all relevant documentation was reviewed, and changes proposed to the design where necessary. By utilising best practice documentation and seasonal sensitivity tables, we were able to show that due a very unique set of circumstances the proposal had the potential to improve the weir site for salmon and trout passage. Changes were also proposed to improve passage for eel and lamprey and reapportion additional flows to the fish pass. This allowed us to demonstrate that the proposal would have no negative impact on the Tweed SAC and could improve the status of several designated and supporting species.
Trex Ecology were asked by Caledonian Conservation Ltd. to deliver EIA technical input into a planning application for a windfarm access route. We provided a complete suite of fish and pearl mussel assessments, followed by design review and an ecological risk assessment of the proposed plans. Mitigation to ensure no damage would occur was identified and carried forward within the EIA.
Subsequently, and working with project partners, we assisted in the discharge of ecology planning conditions for the entire windfarm, including lamprey and pearl mussel survey, along with fisheries data assessment and formation of a management plan.
Trex were contracted by cbec eco engineering UK Ltd to assist with a river restoration design aimed at boosting trout populations within the highly regulated Halligdalselva in central Norway. Following a site visit to assess current habitat quality and identify constraints, we worked with the client to identify options to improve habitat and restore ecological functionality to the reaches to be restored.
Trex Ecology led a team working under the River Forth Fisheries Trust, including experts from Stirling University, Queens University Belfast and Aqua Ecosystems B.V., on a study into stocking the River Dee with juvenile Atlantic salmon as a means to improve the fishery.
This multidisciplinary group looked at all aspects, including an economic appraisal involving hatchery construction and operational costs, to arrive at the recommendation not to stock the Dee.
This conclusion was based on the risk of reducing the genetic fitness of the Dee population, the significant scope for habitat improvement on the catchment, and the major cost identified with no guarantee of a successful outcome.