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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.


 

 

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.