Wildlife
In the lake:
Natural Brown Trout: Brown Trout exist naturally in Trawsfynydd Lake, when the valley was flooded to create the lake a number of fish that lived in the rivers and streams nearby had a new home in the lake. These trout used the Prysor River and Islyn Stream to breed. The main food for the brown trout is flies, but they also eat small fish, worms, maggots and water snails. Most of these trout caught by anglers are returned back to the water. There have been a number of large brown trout caught in the lake recently with the largest being over 9 lbs.
Rainbow Trout: Rainbow trout are originally from North America and are now being used to stock a large number of waters over the world for the enjoyment of the anglers as they grow much quicker the indigenous trout. The fish that are being stocked into Trawsfynydd Lake are sexless so they won’t interfere with the genetic makeup of the indigenous fish. These sexless fish also grow faster. These fish are reared in the lake and released for capture by the anglers. They have a diet similar to the brown trout. The fish in Trawsfynydd are hard fighters and grow quickly due to the abundance of food in the lake.
Perch: Perch have been in the lake since it was created. When the power station was active, the warm water helped the growth rate and the numbers of fish and they were caught in their hundreds. Although the number of perch caught is less these days, there are still a few shoals of fish to be seen and a few big fish still being caught. They enjoy worms, flies and small fish. They spawn on the vegetation in the lake.
Rudd: These fish are thought to exist naturally in the lake since its construction. At one time these were in a large numbers but due to the lack of vegetation in the lake and that all the other species eat them their numbers are low. They feed on small flies and vegetation usually, and they spawn in the vegetation.
Pike: No one really knows how pike came to Trawsfynydd Lake; some believe they have been here since the beginning and the warm water in the past stopped them from growing. Others believe that they have been put in the lake on purpose; fish eggs can be carried easily by birds, and because other lakes in the area hold this species it is possible that this is what happened. The pike are hunters that can eat fish, frogs, water birds and even water voles. The pike spawn in aquatic vegetation. The pike can grow very big and fish have been caught in Trawsfynydd weighing over 30 lbs. The anglers are advised to release the pike they catch as they have a key role in eating the sick or injured fish, and because the bigger pike eat the smaller pike they keep a balance in the ecosystem.
Around the lake:
Otters: These charismatic creatures can travel up to 25 miles in search of food, mainly fish, but they also eat animals such as frogs , small birds and even other mammals.
Can you find otters footsteps as you walk around the lake?
Ospreys:
The ospreys were not recorded as nesting in Wales until the 21st century, but it is strongly believed that they have lived here for centuries. The local osprey family nest near the Glaslyn river, but they overwinter in Africa due to the unfavourable conditions offered by the British winters. They will fly distances of up to 10 miles from their nests in order to feed during the nesting season. They are often seen fishing the lake and the nearby rivers, feeding on a variety of fish. Keep an eye out for them fishing between the months of April and September!