The French coastguard on Tuesday searched for Pierre Agnes, the chief executive of US surfwear retailer Boardriders Inc, after his 36-foot (10.97 m) sailboat was found washed up on the country's Atlantic coast.
The area is known for intense, sometimes unsafe waves and boasts surf breaks pursued by the world's best surfers.
Agnes, 54, had told authorities he was delaying his return because of thick fog, but his 36-foot boat was later found on the beach empty and upside down, about 20 miles from Hossegor, the famed resort.
Rescue services were unable to say if the Frenchman had been alone.
"I'm praying for a miracle but it's just starting to hit me what a profound effect this man had on my life and the surf community at large", he wrote.
Agnes, a father of three, set out in his boat for some solo fishing about 8:30 a.m., according to The Sun.
"I love this man", Kelly Slater, an 11-time World Surf League champion, said in an Instagram post.
A former member of the French national surfing team, he has worked for Quiksilver for 30 years, mostly at the company's European HQ in Saint-Jean-de-Luz, in south-western France.
Quiksilver and Billabong both started out in Australia more than 40 years ago and used surf culture to sell clothing around the world. He left the port of Capbreton at 7:30 am, but never made back to the shore.