Eggs of Rare Ice Age Fish Rescued From Lake Invader
By DAVID GREENWOOD
CONSERVATIONISTS are celebrating the end of a major operation to save rare fish found only in a North Wales lake from the jaws of its arch enemy.
Experts were last night hoping that the unique gwyniad, which was left stranded after the Ice Age in Bala’s Llyn Tegid, will settle down in a nearby lake after a phased relocation offensive.
The gwyniad – otherwise known to scientists as Coregonus lavaretus – is a whitefish, a kind of landlocked herring.
The fish’s future was threatened by a dangerous combination of problems: lack of oxygen in the depths of the lake in summer, human activity and fluctuating water levels.
They were also being targeted by hungry ruffe fish, which were introduced into Llyn Tegid 20 years ago but are now proving a major threat to the gwyniad.
According to Countryside Council for Wales bosses, the aggressive ruffe congregate around gwyniad spawning areas, munching on eggs and young fish.
The CCW joined forces with officials from Environment Agency Wales and the Snowdonia National Park Authority, stripping eggs from spawning gwyniad and transferring them to a better home.
EAWs Richard Brassington said: “These rare fish spend most of their time in the deeper, colder parts of the lake, except at this time of year where they move into shallower water at night to spawn.
“Our fisheries officers and National Park staff have used all their experience and expertise to carefully seine net, a method that minimises damage to the fish and the environment.
“This year we caught 31 fish,” he added.
CCW’s freshwater ecologist Rhi-an Thomas said: “Although this was the final phase of the relocation project, monitoring work will be ongoing.
“During the summer a further survey of the gwyniad will be conducted at Llyn Tegid to monitor any changes in the population.
“Also in a few years’ time a survey at the nearby lake will monitor the success of the relocation project.
“By this time, we hope a new gwyniad population will have been established.”
The Snowdonia National Park Authority’s Rod Gritten said: “The gwyniad, a member of the whitefish family, is a unique species.
We must make every effort to safeguard its future within the park.”
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