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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.

 

West Beck grayling


 

 

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.