Warning to dog owners and visitors as dangerous algae found in Snowdonia National Park lake

Blue-green algae is potentially fatal for dogs and can cause illness in humans. Credit: Snowdonia National Park Authority

Dog owners and those taking part in water sports are being warned to be extra cautious when visiting a lake in Snowdonia.

It follows the identification of blooms of blue-green algae at Llyn Tegid, Bala, in Gwynedd.

Toxins released by the algae are potentially deadly to dogs and can cause illness in humans. 

Snowdonia National Park Authority has warned visitors to “be careful” around the lake and avoid direct contact with the algae.

Blue-green algal blooms can kill fish due to lack of oxygen in the water and the toxins can kill animals and birds.

The algae is a group of bacteria, called cyanobacteria, which release toxins such as microcystins and anatoxins into the water.

Ingestion can cause skin rashes, sickness, stomach pains, fever and headaches in humans.

If a dog swallows water containing the most severe toxins, they may start showing signs within minutes. In less severe cases, symptoms can take a few hours to show.

Outdoor instructor dies after 'significant fall' in Snowdonia
Meet the Welsh Mountain Zoo's first sea lion pup in almost 20 years

Dog owners should call a vet immediately if their pet comes into contact with blue-green algae.

If caught quickly enough, the vet may be able to flush out the toxins before fatal damage occurs.

The current bloom is believed to have been caused by the recent heatwave and dry spell of weather.

The algae can clearly be seen on the banks of Llyn Tegid Credit: Snowdonia National Park Authority

In June, blue-green algae stripped oxygen and killed fish at Llangorse Lake, near Brecon.

Paddleboarders and kayakers who visit Llyn Tegid are being advised to wash their equipment before venturing to other lakes.

In a statement, a spokesperson from Snowdonia National Park Authority said: "Blue-green algal bloom is a natural phenomenon that has occurred in Llyn Tegid for many years. It mostly appears during periods of fine, hot weather and can be easily identified from the bright green coloured scum floating near the shorelines.

"Ingestion or skin contact with the algae is hazardous to human health, and animals in particular are extremely vulnerable. When visiting Llyn Tegid, we ask that lake users familiarise themselves with the safety notices on the foreshore, and to heed the advice not to enter the water when algal bloom is present."