Police today named the fisherman missing from his empty boat off Unst as Karl Anderson, a Baltasound man aged 46, as the search for him was scaled down.
The hunt was launched off the island last night after his 26ft creel boat Kathleen, which he bought in 2006, was spotted with no-one on board.
Shetland Coastguard rescue helicopter, the Lerwick lifeboat, several local vessels and the Baltasound coastal rescue team were all involved in the search for Mr Anderson.
A member of the public alerted Shetland Coastguard at 8.44pm yesterday to say they had spotted the Kathleen with the engine running.
They had taken their own boat out to investigate the vessel and found no sign of the owner, who had not laid any of the creel pots. Shetland Coastguard then sent the coastguard rescue helicopter R102 from Sumburgh to begin a search.
The coastguard helicopter was back on scene in the north of Unst at 1.30pm today and searched from Tonga Stack in the west, round Muckle Flugga in the north and Balta Isle and Huney on the east coast. The search was completed by 2.25pm but nothing was found and the helicopter was back in Sumburgh at 3pm.
Coastal rescue teams are continuing their search between Skaw and Baltasound.
Meanwhile the Kathleen was brought back to Baltasound by local people.
The incident comes 13 years after two Unst brothers, Norman and Cecil Gray, were lost off the north-east of the island with their creel boat Accord, which is thought to have capsized.