Coregonus lavaretus - Gwyniad
The gwyniad is a whitefish - a kind of land-locked herring. In Wales the
only known population lives in the depths of Llyn Tegid (Bala Lake) in the
Welsh Dee catchment. In recent years there have been concerns that
eutrophication (over-enrichment by nitrates and phosphates running off the
farmland around the lake) might threaten the survival of the gwyniad in
this the largest natural lake in Wales. Environment Agency Wales,
Countryside Council for Wales, Gwynedd County Council and others have been
developing a plan to reduce the input of these damaging chemicals to the
lake.
Another threat to this rare species is the ruffe that have
been introduced to the lake recently; these bottom-dwelling perch-like
fish are quite likely to be eating some of the gwyniad eggs. The rare
vendace (Coregonus alba) of Bassenthwaite Lake, in Cumbria, are
similarly threatened now that ruffe have been illegally introduced also to
that upland lake.
The Environment Agency Wales hatchery at Maerdy has been
rearing gwyniad from Llyn Tegid stock; the idea is to help maintain the
natural population until the waters of Llyn Tegid can be restored to a
satisfactory standard.
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