The 2023 Electrofishing Report can be downloaded here
Non-Technical Summary
In the Summer of 2023 NDSFB carried out fish population surveys throughout the Ness Catchment. In order to obtain maximum coverage a number of methods were employed following SFCC protocols. This included Time delineated surveys and area delineated surveys ( semi quantitative surveys). By employing these methods NDSFB were able to carry out a total of 44 timed surveys throughout the catchment and thirteen area-based surveys. Many of the timed surveys were repeated from the 1993 Auris and 2022 surveys allowing comparisons to be made. Area surveys carried on the mainstem River Ness are core sites where a good dataset is available for comparison.
2023 also saw the re-introduction of the National Electrofishing Programme for Scotland. A total of 30 area delineated sites were surveyed throughout the catchment, with 10 multi-pass and 20 single pass methods employed.
2023 was a busy survey year with approximately 90 surveys carried out in total using a variety of techniques and protocols. Timed surveys carried out on the Ness mainstem indicated that fry counts were lower than in previous surveys, this however could be as a result of survey timing. Area delineated surveys however, showed densities to be much better and give a more accurate picture with a comparable dataset from many previous surveys indicating a rising trend in fry and a stable trendline for parr.
Poor catch returns on the mainstem Ness may lead to reduced spawning activity; surveys carried out next year will give an indication on how successful spawning will be. In addition, an investigation into the number of spawners within the river is to be carried out next year and will inform the potential need for a stocking programme.
The Garry restoration project results indicate that stocking has been successful to a certain extent. The presence of relatively good densities of fry and parr throughout the stocking locations, and also in the unstocked Allt Choire a’ Bhalachain, which were derived from natural spawning, show suggest that some fish are returning. However, proof that these returning adults are as a result of the stocking programme is vital, and we await the genetic analysis to confirm this.
In contrast to the Ness mainstem, rivers in the upper catchment have shown encouraging results, the River Enrick, as always producing good to excellent densities of both fry and parr. The River Moriston results were very pleasing with much higher counts and densities compared in previous years. Garry fry counts increased, however, parr densities were considerably lower than in 2022.
NEPS provides us with opportunities to assess sites that in some cases would be overlooked, giving staff the opportunity to fish a variety of habitats, some exceptional, some not so. However, it was pleasing that salmon were captured at all sites bar one. In addition, a solitary perch was captured at a site on the upper Enrick, a somewhat unexpected find so far upstream from Loch Meikle.
Overall, 2023 was busy survey season for all staff, with many miles covered and good coverage throughout the whole system.