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Visiting Snowdonia

Warden Service


The Glutinous Snail Project

14 November 2016

Now that the busy summer months are behind us, the Wardens here at Llyn Tegid can now turn their focus to other issues regarding conservation and recreation. Whilst the upgrading of furniture on our Leisure Network and promoted paths will carry on throughout the winter an interesting conservation project has begun to try and understand more about one of the rarest species at Llyn Tegid.

Working closely with Ian Hughes from Life-Forms, who has worked tirelessly over the last few months to secure the required consents from Natural Resources Wales and funding from the Freshwater Habitats Trust through a Heritage Lottery Fund grant, we now hopefully will be able to study the Glutinous Snail Myxas Glutinosa in great detail. Ian has designed special shelters to be set in Llyn Tegid and with luck will create a habitat for the snail to live and thrive in and hopefully give us an insight into this rare snails’ world.

The Glutinous Snail

The Glutinous Snail

Pollution free, clear waters is what this particular snail thrives on, with Llyn Tegid obviously ticking the boxes as it is the only lake in Britain that it can be found in. Indeed, the Glutinous Snail is protected under the Wildlife and Countryside Act 1981 and is rapidly declining or already extinct in many European countries because of loss of habitat.

The snail itself is no more than 16mm tall and 15mm wide, the transparent mantle covers the shell when it moves giving it a glass like appearance and sticky to touch hence the name!

Myxas survey shelters and their locations

The Glutinous Snail shelters are made of constructed of a specific concrete that will assist in providing nutrients for the Snails.

They are placed in rows of 3 proceeding out into the lake at various depths and at specific locations known only to Ian and the Wardens. Some of the deep water refuges were placed beyond the effects of wave action on the lake bed which may mean they are out of range of snail – we’ll have to wait and see!

The castings are set and secured into the lake bed as seen below. Because of the near oval shape, if the lake level recedes then water will be retained in the bowl section thus not leaving the snail ‘high and dry’. An inlet in the shelters provides access and egress for the snails.

It is our intention to check the shelters from time to time, during different weather conditions and times of year to establish if the snail actually thrive in certain areas of Llyn Tegid or, possibly, that other species of snail might drive them away to different areas.

Snail Shelter

Snail Shelter

In October 2014 we took some Glutinous Snails into an aquarium to take a closer look at what they get up to. By December we knew that they feed on algae coating rock surfaces and that they are very vulnerable to handling. The glutinous layer seems to compensate for a very thin shell in nutrient poor waters but both are very prone to breakage or bruising. By Easter 2015 the snails had bred and in autumn their offspring had produced their own eggs.

Observations of the snails suggest that they benefit from the wave action in Llyn Tegid and the fluctuating water levels as well as low nutrient levels which keep other snail populations low (An added vulnerability for Glutinous Snails appears to be that they have little ability to become dormant and so, when other snail species can sleep through periods of food shortage, the Glutinous Snail cannot, which means that they expend their energy and starve. Therefore in order to ensure adequate food supplies a lack of natural competition is important).

We are still looking into these theories with the shelters being an extension of the aquarium studies; it is a known method, in a known location at known depths, incorporating everything that is currently understood to be 'good' for glutinous snails. Hopefully this project will assist us in learning as much as we can about this fantastic rare creature.

The Snail and its Eggs

Above we see a photo of the Glutinous Snail (attached to the rocks) with newly laid eggs. Hopefully in the near future an aquarium with either be set up in Llyn Tegid Wardens’ Centre or in a local Primary School so we can further study and record the snail to better predict and protect its future.