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Grayling have a stream lined body, a large "sail-like" dorsal fin and a relatively small inferior mouth. A grayling's upper jaw projects slightly beyond the lower jaw. Juveniles are silver/light green with bluish parr marks along the flanks, these fade as the fish reaches 1 year old. Interestingly, a grayling's large dorsal fin is noticeable once they have reached a body length of 25 mm.


Adults have a grey/green back, green sides and a white under-body. A distinguishing feature of the grayling is its large "sail-like" dorsal fin, which has four to five rows of red and black spots on an iridescent background. The dorsal fin of the grayling is larger in males than females producing notable sexual dimorphism, meaning the different sexes can be easily identified. An adult grayling is typically 30 cm in length, but specimens can grow up to 60 cm.

 Grayling captured by GWCT & EA


UK Distribution


Grayling are distributed through the UK and Europe. Grayling reached British rivers when Britain was connected to continental Europe. Their native distribution and genetics reflect dispersal from continental Europe at a time when the rivers on the east coast of England flowed into the Rhine. 


Native Rivers

Likely native UK rivers include Yorkshire Ouse, Trent, Hampshire Avon, Severn, Wye, Thames, Ribble and Welsh Dee. 


Grayling populations from East Yorkshire were transferred into tributaries across Yorkshire. Grayling were introduced into Scotland in the 1800s, and all populations sampled in the study are genetically related, except the Annan. The majority of grayling populations present in the UK are the result of stocking conducted over the past 200 years. There is no evidence to suggest there have been any introductions of grayling to UK rivers from overseas. Grayling are typically a freshwater species, but can tolerate brackish waters at the north of its range, outside of the United Kingdom.



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.