A recent electrofishing survey carried out by West Cumbria Rivers Trust has monitored the fish populations in a stretch of Naddles Beck, which falls largely within Eycott Hill Nature Reserve. The surveys were carried out in September 2019, with the aim of providing follow-up surveys to those carried out at the start of The National Lottery Heritage Fund project in September 2015.

Electrofishing is a common method used to survey fish, which involves creating an electric field in the water in order to temporarily immobilise and net the fish. All fish species are counted and identified and then returned, unharmed, to the river. Additional information on size and age class is also collected for Atlantic salmon (Salmo salar) and brown trout (Salmo trutta), known collectively as salmonid species, in order to measure yearly variations of the juvenile populations and spawning success.

The surveys were carried out at six different points along Naddles and Barrow Beck, two tributaries which flow in a south westerly direction and eventually converge with the River Glenderamackin. Five of the six sites are within the boundary of Eycott Hill Nature Reserve and the Barrow Beck location is further downstream. It is unknown how long salmon have been absent from Naddles Beck but they have been present in the River Glenderamackin at Mungrisdale for a long time.

In 2015, no salmon were recorded at any of the surveying sites, whereas in 2019, eleven individuals were recorded, and present in four out of six sites. Brown trout, stoneloach, minnow and stickleback were also present in Naddles and Barrow Beck in both years. Fish populations are extremely variable throughout rivers and over time, so results from a single year cannot be taken as a statistically sound measure of population size. However, the combined environmental and fish data obtained from surveys can be useful to inform conservation management.

The sites that tended to show larger increases in both salmonids and overall fish numbers were those that had received more management during the duration of the project. Within the livestock-excluded area of alder-dominated woodland planting, salmonids doubled from four to nine individuals, and other fish species increased from six to 98 individuals between 2015 and 2019. In the section adjacent to ‘Slow the Flow’ works carried out in 2017, salmonids increased from four to eight individuals, and other fish species increased from eight to 42 individuals.

Natural flood management practices such as riparian fencing, tree planting and bunding can be beneficial for fish populations as they allow riverside vegetation to recover, providing shade for fish to hide in, increase the amount of large woody debris in the channel for habitat, and provide gravelly deposits which are essential for spawning fish.

Imogen Rutter, Eycott Hill Reserve and Training Officer, said “It’s fantastic to see fish doing better, especially salmon and trout, in the becks around Eycott Hill, which hopefully means the quality of freshwater habitat is improving. This shows how important it is to improve habitat connectivity and restore our river habitats to a high quality.”

Ruth Mackay, Project Officer for West Cumbria Rivers Trust, said “It’s great that salmon are returning to this beck, it shows that all the hard work of Cumbria Wildlife Trust is having an impact and improving the water quality and habitat of this watercourse for the salmon and other fish that live there. Projects like these are really important to create suitable spawning areas and juvenile habitat to ensure the future of this native fish. “

Eycott Hill Nature Reserve is open year round, and it’s free to visit. To find out more go to our website. 

Work at Eycott Hill Nature Reserve is supported by The National Lottery Heritage Fund who awarded £1.6 million towards the purchase price and an ongoing five year programme of conservation and activities to benefit wildlife and people. Located between Keswick and Penrith, near to the village of Mungrisdale, Eycott Hill is 216 hectares of exceptionally rich wildlife habitat and is a Site of Special Scientific Interest for the plants in the swamps and mires and its geology. Car parking and entry to the nature reserve is free of charge.

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