The Apollo’s crew issued a Mayday about 20 miles north west of the islands at 7pm yesterday. Coastguard helicopters based at Sumburgh and Stornoway joined the fishing boat in searching for the man.
Coastguards said French and American aircraft – in northern Scotland on a joint training exercise – had also joined the search operation.
The search operation was stood down at 4.30pm with the agreement of the Apollo’s crew. UK Coastguard duty controller Angus MacIver last night said: “Despite an intensive air and sea search involving the fishing vessel and aircraft rescue resources from Scotland and international military agencies, the missing man has not been located.
“Our deepest sympathies are with the family and remaining crew.”
Weather conditions in the area were described as “very rough” and “challenging”.
A spokesman for the Royal Navy said: “Two aircraft involved in the ongoing Joint Warrior exercise were re-tasked to the area to join the search of the missing man from the fishing vessel Apollo.
“A DA 20 was taking part in the search this morning after being diverted from the Joint Warrior exercise and a US Navy P8 Poseidon Maritime Patrol Aircraft flew from RAF Lossiemouth after being immediately re-tasked.”
A navy helicopter participating in Operation Joint Warrior also helped with the search for the missing skipper of the crab boat MFV Louisa, after it went down off Mingulay a week past Saturday. Chris Morrison, 27, and Martin Johnstone, 29, were lost when the crab trawler sank south of Barra on 9 April.
The skipper, Paul Alliston, 42, was last seen swimming for shore, but remains missing, while Lachlan Armstrong, 27, survived the incident.
The Marine Accident Investigation Branch has launched inquiries into the incidents.