During this warmer weather at Castle Semple when the water at the loch is at its most enticing blue-green algae appear. I sampled the water this week and the main algae was one called Gloeotricia or Gloey for short. This algae can be a skin irritant or even fatal if ingested in concentrations. Light winds push this cyanobacteria to the lochs edge where it may form thick green scums that are potentially toxic. It’s advisable to keep dogs away from these scums as they will lick it off their fur. Water users should wash hands, wet suits etc thoroughly after activity to avoid skin irritations or potential ill health. It is likely this will persist until late August/September and caution is recommended until then.