Genetics

Genetics

The Spey Fishery Board, in close collaboration with Rivers and Fisheries Trusts of Scotland (RAFTS), the Tweed Commission and the Dee District Salmon Fishery Board have taken the leading role in developing a Genetic Analysis Project to enable this. As three of the “Big Four”, our efforts will benefit all District Salmon Fishery Boards and Fishery Trusts throughout Scotland, by collectively establishing a project with which many Boards and Trusts would like to engage, but for which they lack the necessary wherewithal to instigate individually. The Spey Fishery Board believes that this project is the logical, crucial and fundamental next step towards the creation of new and accurate plans for the management of salmon populations throughout Scotland.
Background

An increasing number of behavioural and genetic studies have shown that the Atlantic salmon is structured into multiple, distinct breeding populations. The evidence shows that salmon in different river systems belong to different breeding populations and stocks in all but the smallest rivers can generally be expected to contain many breeding populations which are reproductively and genetically distinct. In practical terms the Spey will have a salmon population that is distinct from that of other Scottish Rivers and within the Spey, tributaries such as the Fiddich, Avon and Tromie etc will each hold distinct sub-populations.

Breeding populations are the fundamental units underpinning recruitment and defining the character of a river’s salmon stock. It is therefore essential to understand a river’s population structure for the development of effective stock conservation and management plans. Identifying breeding populations can be achieved by the analysis of heritable variation in the DNA of salmon. Many people are familiar with DNA analysis, whereby genetic variations in human beings are used to determine paternity or identify criminals with crimes they have committed. These techniques can also be used to investigate population structuring in Atlantic salmon stocks as each Atlantic salmon has a unique combination of genetic variants by which it and its offspring can be identified. However, such a project will be expensive and time-consuming to undertake and we may not know the results for several years.

Progress to Date

In early 2009, Rivers and Fisheries Trusts of Scotland (RAFTS) employed two molecular geneticists and a part-time laboratory assistant to undertake the FASMOP (Focussing Atlantic Salmon Management on Populations) genetic analysis project. They began work in May 2009, generously supported by the Scottish Government’s Marine Scotland (Science) Freshwater Laboratory at Pitlochry, who have provided laboratory and office accommodation for the project.

Meanwhile, the former Spey Research Trust (SRT) conducted a desk-based study to identify potential sub population areas within the Spey and its tributaries. Major physical variations in the nature of a river produce associated changes in fish habitat. For example, lochs, slow meandering stretches of river, rapids and gorges are not generally suitable for salmon spawning and will indicate a fragmentation of both spawning habitat and juvenile rearing areas. Using natural features and tributary confluences, the SRT’s desk-based study produced a map of the potential sub populations within the catchment, showing estimated 30-50 potential sub-populations of Atlantic salmon.

The SRT also collected around 50 tissue samples from each of these estimated sub-populations during routine electro-fishing surveys, in order to determine whether they do indeed represent a discrete population. These tissue samples are being stored with the aim of having them genetically analysed in a project which has four main components:

Spey Salmon Population: To identify the Spey salmon breeding population, separate to those of other Scottish Rivers.
Spey Salmon Sub-populations:
To identify and map the Atlantic salmon sub-population structure within the River Spey, together with their strengths and weaknesses (abundance) and an indication of run timings.
Hatchery Influence:
To identify the genetic make-up of the salmon broodstock collected within the SFB hatcheries and determine the contribution of the hatcheries’ stock to the rod fishery.
Trout Population Structure:
To consider expanding this approach to sea trout and brown trout populations within the Spey.

Marine Scotland (Science) – are also undertaking a genetic analysis of marine salmon under the EU-funded SALSEA Merge Project, which it is hoped will determine their regional origin within Scotland. It is expected that this will contribute to achieving the first component above. We have been working closely with Marine Scotland (Science), as part of the FASMOP Steering Group, to develop this project further so that we can undertake a Spey-specific analysis, aimed initially at achieving components (ii) and (iii) above. For the latest news see the July 2011 Briefing

River Spey Benefits
The genetic analysis of scale samples from River Spey salmon will produce detailed data on the breeding populations and biological character of Atlantic salmon stocks within the River. This will provide an insight into the structuring of the salmon breeding populations which will allow the SRT and SFB to focus their stock assessment and management of the fishery more precisely on the breeding populations within the River Spey catchment. Furthermore, our hatchery broodstock are taken from known locations and so additional information on tributary sub-population structure will be gained; and samples from rod-caught adults can also be matched to the sub population data from juveniles caught by electro-fishing, which we hope will make it possible to identify when specific tributary offspring are captured in the rod fishery, thus providing us with an indication of run timings.

The Spey Fishery Board has operated hatcheries for a number of years. Stocking fish into a river where wild fish are present is a contentious issue and we are repeatedly asked whether we can justify the operation of our hatcheries, let alone their cost. We have always believed that we have operated them on the basis of sound advice, following extensive scientific research and analysis. We believe that:

we take less than 1% of the fish from the catchment to use as broodstock, thereby minimising the impact on natural spawning;
the management and operation of our hatcheries is undertaken to the highest standards;
particular care is taken to ensure that our broodstock progeny is planted in the same areas as their parental origin; and
80% of that progeny is planted in areas which would otherwise be inaccessible to naturally spawning fish.

We are therefore confident that our hatchery operations are not causing any harm to the River Spey catchment. However, we have yet to confirm whether these operations are positively benefiting the catchment. Catch numbers have been rising over the last few years and until 2009 have been over 10% above the ten-year average of 9,100. What we currently lack is the scientific evidence to prove that this is due, even in part, to our hatchery operations and to confirm that we are actually doing some good, rather than merely not doing any harm. The logical and crucial next step in our fisheries management work is to analyse our fish stocks. Only then will we know if our hatchery operations are an appropriate way of enhancing the fish population within the River Spey catchment, without compromising the conservation of natural stocks. Initial results from tissue samples collected from hatchery broodstock and from the rod fishery were preseneted at the 2011 RAFTS conference by Dr Mark Coulson (RAFTS) and SFB director, Roger Knight. Click here to view their presentation.

Funding
The genetic analysis project will be expensive and time-consuming to complete. The Spey Fishery Board is particularly grateful to the HDH Wills Trust, the Robertson Trust and the Scottish Government for their generous support for this important project.

Conclusion
If we can identify the different fish populations in the River Spey, their individual distinct habitat and their relative strengths or weaknesses, we will be better placed to illustrate the impact that further incursions into the Natural World by mankind will have. Pin-pointing the different fish families is the logical, crucial and fundamental next step towards a new and accurate plan for the Management of Fish Populations in the Spey Catchment.