Police are wanting to speak to anyone who may have witnessed an altercation outside a pub in Mossbank in the earlier hours of Saturday morning, after a man was seriously injured.
Officers were called at about 12.30am to a report of an incident outside the Welcome Inn.
As a result of the incident a 37-year-old man was injured and has been flown to Aberdeen Royal Infirmary for further treatment.
Police said a 42-year-old man has been arrested in connection with the matter and remains in police custody.
Anyone with information regarding the incident can contact police by phoning 101, calling Crimestoppers anonymously on 0800555111 or going to Lerwick Police Station.