DOG owners are advised not to let their pooches into potentially poisonous parts of water at Castle Semple in Lochwinnoch.

Staff say the toxic blue green algae - called Cyanobacteria - has been building up in the loch in the warm weather and can kill a dog within hours.

Symptoms include itching and red sores that come on suddenly after being in the water.

If dogs lick their fur afterwards, they can become ill and in some cases, being in contact with large amounts of the distinctive bright green bacteria can cause death.

Castle Semple countryside officer, Alan Brown said: "As it has been warm weather with very light wind, the blue-green algae or Cyanobacteria has been building up along the shores of the loch.

"During the nice weather it has floated to the top of the surface and blown to the shore where it has been accumulating.

"In stronger winds or rainfall it breaks up, flushes out and disappears.

"Dog owners should be extra careful anywhere along the shore and to watch out for a thin layer of the bright blue-green algae.

"It has potential for a dog to become ill if they drink the water or lick their fur after being in the water.

"It is relatively light at the moment but has potential to accumulate.

"People who swallow the water if they are swimming might have a reaction too so are advised to be cautious."