Blue-green algae identified in North Mainland loch

Warning blue green alge - gluss water

Shetland Islands Council’s Environmental Health team has received notification that Gluss Water, Hamnavoe near Eshaness may contain blue-green algae.  

A dog owner whose animal turned poorly after being in the loch contacted the Council to pass on their concerns about possible toxicity in the water.  The dog has received care from a local vet and so far is responding to treatment. 

Current warm weather conditions across Shetland mean that toxic algal bloom is very likely in local lochs.  

Parents with young children and dog owners are advised to be cautious around bodies of fresh water which may present a toxic risk if blue-green algae is present.  Children and animals should not drink or enter the water and should avoid contact with any algal scum.  

Warning signs will be erected next to Gluss Water and adjoining landowners have been advised of the situation, as have NHS Shetland and Shetland Angling Association. 

Blue-green algae exist in fresh waters and can collect to form ‘blooms’ looking like blue-green paint, in the water or on the shore line.  Blue-green algae can be toxic and give rise to adverse medical effects, include skin rashes, eye irritations, vomiting and diarrhoea, and fever and pains in muscles and joints.  Toxic algae have caused deaths of livestock and dogs.

The treatment of water supplies removes blue-green algae and additional treatment may be applied to destroy or remove toxins should they arise.  The actions currently taken are precautionary.

If anyone suspects blue-green algae at other locations in Shetland, please submit a notification via the “Bloomin’ Algae” App, available to download for free.

For further information, please contact Environmental Health on 01595 745250.


  • Some blue-green algae may give rise to adverse medical effects - but not always.  The behaviour of algae is erratic and the level of its toxicity can fluctuate; it can appear one day, be dispersed by the wind and mixing and re-accumulate at any time. 
  • Gluss Water can be located through the What3Words app - https://w3w.co/script.lifeboats.supply and the OS Grid reference is HU253808
  • More details on the “Bloomin’ Algae” app can be found on the webpages of the UK Centre for Ecology & Hydrology 
     

Published: 15th June 2023