Freshwater Lochan Survey

As you explore Coigach and Assynt you can’t help but notice the enormous amount of freshwater lochans; it’s no wonder that this is an important habitat for wildlife but also a large attraction for visitors and anglers. Many a photographer, artist and ecologist have flocked to the area to see the beautiful views the lochans enhance, and the wildlife they sustain. Within Assynt alone, angling has been found to be worth £345,840-£432,300 per annum to the community.

While we have a reasonable amount of data on the rivers and burns within the area, only the annual catch data provided by anglers existed for the lochs until recently. This project built on this existing knowledge. It involved the various stakeholders, anglers and owners, within the community and aimed to help with management of the resource for the benefit of the users and the fish.

The aims of this project were to:

• Generate greater awareness and knowledge of Assynt and Coigach’s freshwater environment and its importance to the health of the wider environment and also economy of the area.
• Focus on the fish species present in the area’s freshwater lochans; identifying the extent and range of different species, and what factors determine their presence or otherwise.
• Help to build a greater appreciation and protection of this important asset from an environmental, social and economic perspective.

One of the surveyed species: Trout ©  A. Beynon-Jones

West Sutherland Fisheries Trust identified the lack of information as a problem, as a problem and working with Coigach & Assynt Living Landscape Partnership Scheme have increased the understanding of what the current situation in our lochans is. The findings have now been gathered into a report and will help develop future management plans.

One of the species found within the diet of surveyed fish: frog hopper © S. Marshall

Dr Shona Marshall from WSFT and a team of 12 volunteers and staff set out to carry out the research over 2018/19 in over 20 of the myriad of lochans, capturing and analysing three of the seven species occurring within the freshwaters of Sutherland: trout, Arctic charr and minnows. Using gill nets, samples of species within each loch were analysed, and indicate that the fish populations seem to be healthy and have a balanced natural diet. Further research using eDNA could provide further results on the species composition of the lochs.

Researchers using the gillnet survey technique © A. Rawlings

This initial pilot study brought some management recommendations to light that would benefit the lochans within Assynt and Coigach. Dr Shona Marshall noted that “From sample catches we were able to produce a trout length – weight guide for trout calibrated to the local populations, and also confirmed Arctic charr in one new location. Unfortunately, minnows that have been introduced as bait were found in four new locations.” The recommendations have been shared with the managers of the fisheries within the area. The study also brought to light future research that would help us understand these freshwater systems better as well as looking after the fish stocks within them.

Thank you to the players of the lottery through the National Lottery Heritage Fund and to NatureScot for their support of the project. Also thank you to the West Sutherland Fisheries Trust and Dr Shona Marshall for undertaking this project.

You can download the full report here: CALLP P03 Freshwater Lochan Survey FINAL report