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Seasonal Movements and Habitat use of Grayling in the UK


Durham University was commissioned by the Environment Agency and the Grayling Research Trust to examine the seasonal movements and habitat use of European grayling Thymallus thymallus in unregulated rivers dominated by surface flow. The aims were to: The study was carried out mainly on the River Rye catchment in North Yorkshire. Radio-tracking was undertaken on the Rye over two periods, January to July 2004 and October 2004 to January 2005, as well as habitat surveying, environmental monitoring and limited electric fishing surveys and mark–recapture. A subsidiary radio-tracking study was carried out on the River Ure, North Yorkshire, between February and April 2004.

 

tagged grayling

 

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.

 

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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.