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River Wylye (Hampshire Avon)


The Wylye Project, led by Anton Ibbotson, Game and Wildlife Conservation Trust, is now in its 18th year. Rich Cove, Environment Agency, is collaborating with Dr Ibbotson to analyse the long-term data-set. Continued funding from Grayling Research Trust will depend on progress made to date and on future prospects.



The Grayling Research Trust awards small grants for study and research related to grayling, their habitats, ecology, water quality and environment. The trust has been in a fortunate position where it has funded or part-funded a number of regionally and nationally important projects. A selection of such projects can be seen below.

Grayling Spawning Survey

The GRT has launched a project to record sightings and the timing of grayling spawning; i.e. actually laying eggs, rather than just pre-spawning movements onto spawning areas, or pre-spawning behaviour, which are also of interest, but take place over a longer time. This study is being undertaken because there is little information on the timing of grayling spawning and how this varies across the country/continent. It is hoped that the findings from this study will be used to inform the planning of in-stream engineering works and help protect important spawning habitat. Results are mapped. Further Details.

Grayling Weight Survey and Condition Calculator

The GRT has launched a project to record the length and weight of grayling. The length/weight (condition factor) of a grayling may vary across the country/continent. There will be seasonal variation, as fish lose and gain weight depending on the food availability and the onset of spawning. This study is being undertaken because there is little information on the condition factor of grayling. We have developed Fulton’s Condition Calculator Tool so you can measure of an individual fish’s health. Further Details.


UK Grayling Genetic Census

The study demonstrated that UK grayling display pronounced genetic structuring and restricted connectivity between all but a few populations. Despite the high degree of differentiation among the 27 populations sampled, analyses of microsatellite data revealed four or five groups (depending on the analysis method) that, with the exception of two populations, grouped largely by geographic location. Further Details.




Review of Grayling Ecology

This review of grayling, ecology, status and management practice concentrated on the UK, but included published literature from Europe and North America, When appropriate. The project was funded by the Environment Agency, and carried out by the Centre for Ecology and Hydrology (the group is now part of the Game and Wildlife Conservation Trust) with the assistance of The Grayling Society and The Grayling Research Trust. It produced recommendations for best management practice and resulted in a guidance leaflet for internal and external circulation which promotes the key issues. Further Details.

Seasonal Movements and Habitat use of Grayling in the UK

A series of recommendations were made based upon this research. The adaptive pattern of seasonal movements by grayling in many rivers, which probably helps to enhance survival probability and sustain populations, especially in those rivers with variable flow and/or greater spatial dispersion of key habitats, needs greater consideration in river management. This study, as well as other published material, suggests that many barriers across which brown trout can gain easy access may not be easily passed by grayling. Careful assessment of the need for new obstructions, operation of existing structures and possible removal of potential barriers to movement should therefore be considered. Further Details.

The Perceived Decline of Grayling in Yorkshire

Following a request by Steve Rhodes for investigation of a perceived decline in Yorkshire Dales grayling populations, The Grayling Research Trust sponsored an M.Sc. project at University of Hull. The student, David Johnson, has examined Environment Agency records and a wide range of environmental data to tackle this complicated problem. The study confirmed that there has been a decline in grayling populations over the last 15 years for specific rivers and locations. In addition, angling catch return data suggested that, on some rivers, grayling populations began to decline in the 1980s. Further work is needed to identify the possible causes for the change in these populations, although it seems likely the factors involved vary in their importance from river to river. Further Details.

Genetic Assessment of Welsh Dee Grayling Populations

A study of the Welsh Dee population undertaken by Harriet Johnson and her supervisor Martin Taylor at Bangor University has been written up as an M.Sc. thesis. For this study, Rich Cove, Environment Agency, organized a group of anglers to take mouth swabs from 404 grayling caught along 85km of the Dee catchment. The swabbing technique, routinely applied to humans but not previously tested on other animals apart from bluegill sunfish, was 98% efficient in yielding high-quality DNA. Surprisingly, the genetic analysis revealed no population genetic differentiation within the Dee. This result could indicate that some substantial weir structures, most notably those around Llangollen, do not prevent upstream movement of grayling in the Dee, although it is also possible that genetic differentiation is present, but not detected by the genetic markers that were available. If weirs on the Dee are passable by grayling this does not mean that other apparently similar obstacles will necessarily be negotiable on other rivers. All depends on the structure of the potential barriers and in this regard it may be informative to examine the weirs on the Dee in some detail, if indeed they are passable. Further Details.

Long-term Monitoring: River Wylye (Hampshire Avon)

The Wylye Project, led by Anton Ibbotson, Game and Wildlife Conservation Trust , is now in its 18th year. Rich Cove, Environment Agency, is collaborating with Dr Ibbotson to analyse the long-term data-set. Continued funding from Grayling Research Trust will depend on progress made to date and on future prospects. Further Details.




Studying the grayling population in the River Seven

A small team of Sinnington Angling Club members (Yorkshire Derwent) are involved in an important study of the health and numbers of grayling in their club waters, by supplying scales of caught fish to The Grayling Research Trust for assessment.  The East Yorkshire Rivers Trust (EYRT) are heading the SAC team. The project also has the interest of The Grayling Society, the Environment Agency. Further Details.



Long-term Monitoring: South Calder Water (River Clyde)

The South Calder Water Project, led by Willie Yeomans of the Clyde River Foundation, is in its fourth year of Grayling Research Trust sponsorship. Sampling suggests that the population may be more unstable than had been anticipated. No grayling were caught in 2011 but young recruits appeared in 2012. Grayling Research Trust will therefore continue funding the project, which should provide a unique opportunity to monitor the recolonization dynamics of a population vulnerable to periodic crashes. Further Details.



GS Symposium Speakers

GRT Funded MSc, PhD Studies

Two degree project interim reports were among presentations at the most recent Grayling Society symposium. Both studies are currently funded by the GRT and both operate on a premise that alongside the intrinsic value of grayling as a game fish, their survival challenges provide early indication of problems that are or will likely become problems for other salmonids.


Stephen Gregory (Game and Wildlife Conservation Trust) described an MSc study plan for statistical mining of the existing Wylye Study data, questioning the effect of extreme climate events on grayling population dynamics. He emphasized that the GWCT now leads all processing aspects of the 30-year Wylye Grayling Study (WGS) dataset - the longest and most complete in Europe...possibly in the world.


Vanessa Huml's (Manchester Metropolitan University) PhD study is titled Assessing adaptive genetic variation for effective management and conservation of European grayling. Read her description of planned work, noting reference to new sequencing technology and reference to the four U.K. genetically distinct groups identified in the earlier genetic census funded by the GRT.


The two studies both look at grayling population health/stability under extant environmental conditions but the doctoral work extends inquiry to genetic proclivity for survival ('evolvability').


Both investigators will submit detailed results for publication here after review in their respective peer literature.