Public health announcements

23rd July 2021


Blue-green algae can be present in lochs and other water bodies in Shetland, especially in warmer weather, and people are asked to exercise caution where blooms can be seen. Dogs and livestock should be kept away from these lochs to prevent any potential health effects. The public are advised not to bathe in any affected waters and fishermen should also exercise caution.

Anyone coming across any suspected algal blooms is encouraged to make any reports (photographs can also be uploaded) using the ‘Bloomin Algae’ app. This is available to download from a link online at .

SEPA and local authorities will receive alerts when local blooms are reported via the app. These details will then be assessed remotely and a judgement made as to whether it is blue-green algae and if a sample of the water should be taken.

If officers are confident from the visual evidence or analysis that it is a blue-green algal bloom, then appropriate action and warnings can be issued locally. Any affected areas identified in this way will be listed on the SIC Environmental Health website at .

The public can report any sightings directly to SEPA via their online form at or by calling their Pollution Hotline on 0800 80 70 60.

or to the SIC Environmental Health Team on 01595 745250 or by emailing or via Facebook.

Location of most recently reported Blue-Green Algal Blooms

Areas / Lochs Affected Grid Reference
Burn of Griesta at Tingwall Garage HU 41 44
Ronas Voe, Shetland Islands (ZE2 9RX) HU 2769 8486
Easter Lother Water and Sprittery Hole Fair Isle
Burga Water, nr Vidlin HU481642

Further Information

  • Blue-green Algae exist in fresh waters in Great Britain and throughout the world; they are noticed when their concentrations increase to form "blooms" and when they form scums - looking like blue-green paint - or when they collect on the shore line
  • Being in direct contact with Blue-green Algae may give rise to adverse medical effects including skin rashes, eye irritations, vomiting and diarrhoea, fever and pains in muscles and joints. Toxic algae has in the past caused deaths in 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
  • The behaviour of Blue-green algae is very erratic. The level of its toxicity can fluctuate; it can appear one day, be dispersed by the wind but then re-accumulate and grow quickly again at any time