The Tweed Foundation’s monitoring programme last summer concentrated on the Teviot, Till, Upper Tweed, Gala and Leader sub-catchments. The reports for each sub-catchment can be viewed here.
In line with other rivers around the UK, and particularly those north of the Tweed, the Tweed Foundation biology team recorded mixed results in the Tweed District, with numbers of fry recorded showing large variations on previous monitoring of the same sites (on their normal three-yearly cycle). Potential causes of these variations on Tweed, particularly those that showed a marked downward trend in numbers, include the sustained flooding during the winter of 2015/16, or a reduced number of spawning fish. Flooding could well have led to redd washout, with eggs being displaced from gravel, or disruption of spawning by the adults. Not all rivers are the same! – and on other rivers in the UK, different factors have been sited as contributing to their drop in juvenile numbers.
As this winter Tweed has not seen the high water levels and floods of 2015/16, the Tweed Foundation will be re-surveying some of last year’s sites to see if fry numbers are higher having not had to cope with constant floods.
The broodstock for the fry of 2017 were the adult fish last year, when autumn catches were low, and so if low fry numbers persist in these areas of the catchment when re-surveyed this summer – without the flooding effect – it will point to numbers of autumn fish being an issue.
Watch this space………………
The Tweed Foundation, a company with charitable status, aims to protect and enhance the economic and social value of the fishes of the Tweed and the Eye through the study, maintenance and restoration of their populations, ecosystems and habitats and the encouragement of wider participation in angling. Further information on the work of the Tweed Foundation can be found at: www.tweedfoundation.org.uk