Llyn Padarn, the long lake that stretches from Llanberis towards the sea, hides one of the most remarkable creatures in Eryri (Snowdonia). Deep in its cold water lives the Arctic charr, a fish left behind when the glaciers retreated at the end of the last Ice Age. In Welsh it is called “torgoch”, meaning “red belly”, after the bright colour the males take on at spawning time.
An Ice Age survivor
Arctic charr are a cold-water species, found mainly in the far north. In Wales they survive in only a handful of deep lakes in Eryri, with Llyn Padarn, Llyn Cwellyn and Llyn Bodlyn the best known. These populations have been isolated for thousands of years, which makes each one special.
The charr need cool, well-oxygenated deep water to survive the summer, and clean gravel to spawn on in winter. That combination has become harder to find.
Why the torgoch declined
Surveys at Llyn Padarn from the late 1990s to the mid-2010s showed a steep fall in numbers. Several pressures came together:
- Nutrient pollution: nutrients from sewage, farmland and development feed algae. When the algae die and rot, they use up oxygen in the deep water the charr depend on. Our piece on slow release fertilisers looks at one way farmers are changing how they feed the land.
- Warmer summers: climate change shrinks the cool, deep refuges the fish need.
- Lost spawning grounds: slate quarrying changed the lake’s shallow edges, and the building of the Dinorwig power station cut off access to historic spawning areas in neighbouring Llyn Peris. The charr now rely heavily on the Afon y Bala, the short river between the two lakes, where floods and water releases can wash eggs away.
Bringing them back
Natural Resources Wales has run a conservation breeding programme for the Llyn Padarn charr since 2012. Eggs are collected from wild fish spawning in the Afon y Bala, reared at NRW’s Cynrig hatchery and the young fish returned to the lake. In October 2020, for example, around 7,500 juvenile charr were released after about ten months in the hatchery.
Numbers have risen since the programme began, but most adult fish in the lake now come from the hatchery, which shows how much the wild population still struggles to breed on its own. Work continues to reduce pollution and restore habitat, including community projects led by the North Wales Rivers Trust, and NRW has been establishing a back-up population in Llyn Crafnant to help secure the species’ future.
There is good news on water quality too: Llyn Padarn is a designated bathing water and has been graded “excellent”, a big improvement after the algal problems of the past.
Seeing Llyn Padarn
You are very unlikely to see a torgoch, which spend most of their lives in deep water, but the lake itself is one of the loveliest spots in Eryri.
- Padarn Country Park wraps around the northern shore, with woodland walks, the old quarry hospital and views across to Dolbadarn Castle and Yr Wyddfa (Snowdon).
- The lakeside path makes an easy, mostly level walk from Llanberis.
- On the water: the lake is popular for swimming, paddleboarding and kayaking. Cold water is a serious risk even in summer, so go with a friend and wear a bright hat or tow float. Our guide to wild swimming in Eryri has more.
Help the charr by keeping the lake clean: take litter home, clean and dry kit between waters to avoid spreading invasive species, and never release fish or bait. Invasive species are a problem on land too; see tackling invasive rhododendron in Eryri. Find out more about the area’s creatures in our wildlife guide.
Making a trip of it
Llanberis is the start of the Llanberis Path up Yr Wyddfa and the Snowdon Mountain Railway. For somewhere to stay, Caernarfon is a short drive away, with characterful options such as the Black Boy Inn, a historic inn within the old town walls. Our where to stay guide has more ideas.
FAQs
What is a torgoch?
The Welsh name for the Arctic charr, meaning “red belly”. It is a cold-water fish surviving in a few deep lakes in Eryri.
Why are Arctic charr rare in Wales?
They need cold, clean, oxygen-rich water. Pollution, warmer summers and lost spawning grounds have all hit them.
Can you swim in Llyn Padarn?
Yes, it is a designated bathing water. Take care: the water is cold and deep.
