In the world of fly fishing, trout dominate the headlines, but in the past grayling were considered to be the equal of trout for sporting appeal – hence Izaac Walton’s The Compleat Angler (1653) describes them alongside each other in his chapter on ‘how to angle for a trout or grayling in a clear stream’. River keepers once culled grayling in the mistaken belief that they competed with trout, but research has now shown that the two fish species have different and complementary feeding habits and occupy different river habitats.
The genetics of native UK grayling show that they survived in Ice Age refuges and recolonised Britain’s rivers early in the Holocene, before the Doggerland land bridge to the Continent was cut off. Studies of fish-scale remains from archaeological sites indicate that grayling were regarded as a valuable food resource throughout prehistory and into the medieval period – their remains have been found in medieval pit complexes in Anglo-Scandinavian York, as well as in deposits dated to AD 1350-1450 at Corve Street, Ludlow, Shropshire.
Grayling are very sensitive to pollution and environmental degradation, hence their role as a bellwether for the state of Britain’s rivers and streams. Agricultural nitrates, sewage spills, or acid rain runoff trigger an immediate population drop, as does excess sediment, which coats and suffocates their delicate eggs. Water abstraction, higher summer temperatures, and drought drastically reduce juvenile survival rates, since grayling need cool, clean, well-oxygenated, fast-flowing water and healthy gravel habitats to thrive.
