Professional surfer Arran Strong, 28, presumed dead after going missing of the coast of Portugal

Arran Strong, 28, went missing a mile off the coast of Portugal on Monday and authorities halted the search on Thursday. (This video contains AI-assisted content)

Professional surfer Arran Strong was presumed dead four days after going missing off the coast of Portugal in a tragic incident, the sports governing body in the UK confirmed.

The 28-year-old was a mile off the coast with his coach, Jose Maria Pyrrait, when the pair stopped to take a drink of water and take pictures. After taking a break for a few minutes, Pyrrait let Strong go ahead of him and then lost sight of him.

"In short: we stopped off Arrifana to drink water and take some pictures. We were there for a few minutes talking, when we started again," Pyrrait wrote in a post on Instagram. "I let him go ahead. Since my pace is faster. I always do that. When I would catch it and get a short lead I’d stop and wait for it."

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Arran Strong of Great Britain looks on during Qualifying Round 2 of the ABANCA Pantin Classic Galicia Pro on Aug. 21, 2020, in Pantin Beach, La Coruna, Spain. (Jose Manuel Alvarez/Quality Sport Images/Getty Images)

"This time it was no different, but when I stopped to wait, I saw your board drifting about 100 meters away. I paddled as fast as I could to get there, diving repeatedly looking for it, but we were in a really deep area and visibility was very short."

Pyrrait said he immediately reached out to his partner on shore for help, and a local fisherman picked him up. They spent nearly 2 1/2 hours "scouring" the area for Strong using the boat’s sonar.

The Autoridade Marítima Nacional (AMN) told BBC Sport it was alerted to Strong having difficulties in the water at 11:33 BST Monday.

"The