All Creatures Great and Small

All Creatures Great and Small

Reuben Sweeting, Flow Country Rivers Trust
11 April 2022

The rivers of Scotland have long been famed for that great and iconic fish, the Atlantic Salmon. This amazing fish was once revered for its seemingly endless supply which year after year held up to the onslaught of nets that greeted the fish as they hit the coast on the return leg of their journey. Here in the Flow Country, countless old records tell a story of the days when the rivers teemed with salmon and of the bumper catches enjoyed – one single sweep of a net on the Thurso River accounted for 2560 fish on a single day in July in the summer of 1743!

Now, much has changed. The netting stations have faded slowly into history and the once plentiful fish have become ever less reliable. But attitudes have changed too: the salmon is no longer regarded as a commodity to be plundered at every opportunity but rather given the protection it deserves and needs. Through efforts to better understand some of the issues facing our salmon, numerous surveying and monitoring programmes have become recognised as ‘standard practice’ across Scotland as tools to guide management decisions. Now, while still in its infancy, another programme is being rolled out across the North.....


How will SmartRivers help?

The SmartRivers Project, designed by Salmon and Trout Conservation (S&TC) is a sampling programme for stream invertebrates. It is based on kick sampling which is the process of agitating the river’s substrate and collecting the dislodged aquatic insects in a small handheld net. SmartRivers is already well established in England and until recently has been focused on the chalk streams of the South and the many issues found there. Through the identification of the invertebrate species collected and using powerful biometric tools, it is possible to assess water quality and to identify issues such as sediment, phosphorus, chemical, organic, and flow pressures all of which can be detrimental to aquatic life. Beyond this, the Trust hopes that the study of invertebrate communities will help track the future effects of climate change and changing conditions in the northern rivers.

Invertebrates share the same waters that young salmon and trout do, making up much of the fish’s diet. But the importance of invertebrates doesn’t stop there. Like salmonids, many species of these tiny aquatic creatures are sensitive to the same pressures and rely on cool, pollution-free waters to thrive. By analysing samples and comparing them against benchmark values, even subtle changes can be identified and we will be able to pick up issues that standard hydrochemical tests might miss.


Some of the Trust’s invertebrate identification team. Photo A Youngson.
Some of the Trust’s invertebrate identification team. Photo A Youngson.

Progress so far

The Flow Country Rivers Trust had the honour of becoming the first river in Scotland to enrol as a SmartRivers Hub. Like so many things, the project was hampered by Covid restrictions over the last two years but began with benchmarking of the River Halladale by SmartRivers professionals in the autumn of 2020 and spring of 2021. The life-cycles of the various invertebrate species are different and autumn and spring sampling is necessary to identify all the species that are present.

The Halladale River sits in the middle of the Trust’s area in both geographical and water chemistry terms making it an ideal place from which to grow the project. Funding support from both the Caithness and Northern District Salmon Fishery Boards enabled the project to get underway. Benchmarking of six sites spread across the Halladale catchment produced incredible results with a wide range of species found in abundance – S&TC describing it as jaw-droppingly good. For S&TC, the inclusion of Scottish rivers into the SmartRivers programme has made it possible to find out what these relatively pristine rivers can produce. From the Trust’s point of view, the benchmarking exercise represented an ideal opportunity for its volunteers to gain knowledge and experience of invertebrate surveys and to begin acquiring the skillset required to add to the core SmartRivers programme.

Thirteen volunteers were enlisted, all with connections to the many rivers across the Flow Country, and they have received training on the standardised methods for performing kick sampling and on preserving the invertebrates collected in alcohol. Preserving the samples means that they can be retained without degradation and it allows identification and analysis to be carried out indoors in a more convenient environment. Additional training in this more challenging aspect of processing samples and identifying the species found was provided by professional ecologists, again through SmartRivers. This now puts the Trust in a strong position to continue surveys at any river site where required. Indeed, the most recent collection of samples from the Halladale sites in autumn 2021 was undertaken by volunteers as we begin to take a more independent route.

While still in the process of learning and developing skills, the Trust realises the importance and benefits of continued professional input and support and funding has also been secured from the RSPB and from Strath Halladale Partnership to enable the professional analysis of samples from key new areas of the river to continue.

Complementing the other types of survey already carried out across the Trust’s area, our new holistic approach to the health of our waters and the life within them is an improvement from days gone by and proof that today's efforts are focused not just on salmon but on all creatures, great and small.

Further information 

To find out more about becoming a SmartRivers hub and the benefits it can bring to local river restoration projects, and in shaping national water policy, please visit the SmartRivers page or email smartrivers@salmon-trout.org