Mr Mearns, the director of Blue Water Recoveries, led a team on the vessel FPV Morven while the UK Air Accidents Investigation Branch (AAIB) also sent a team aboard its Geo Ocean III.
Sala's father has spoken of his anguish at the discovery.
Sala's distraught dad told local broadcaster Crónica TV that "he can not believe it". This is a dream.
"One or two of the strikers we were talking about didn't really want to come in the circumstances", Warnock said at a news conference ahead of Saturday's home game against Bournemouth.
"It is nearly the whole plane and we expected to find debris but most of it is there and there is the possibility of [finding] Sala's body". "It is broken but most of it is there".
Even if investigators are able to analyse the wreckage up-close, the reason for the plane ending up on the bottom of the Channel may not be established.
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The body was picked up on the vehicle's underwater cameras. "They saw the registration number".
The Geo Ocean III has a crane and a heavy-duty winch at its stern. "That is probably what they are evaluating", Mearns said.
Mearns explained the investigation had then been handed over to the AAIB.
"But tonight they have heard devastating news and in respect of the families I won't comment any further about what has happened", Mearns was quoted as saying to Sky News. "The AAIB is now considering the next steps, in consultation with the families of the pilot and passenger, and the police".
Sala, 28, and pilot David Ibbotson, 59, were flying in the single-turbine aircraft from Nantes, in northern France, to Cardiff, in Wales, when it disappeared from radar near the Channel Islands on January 21.
The find will hopefully bring closure to family and fans of Sala and his pilot, David Ibbotson, ending the story that rattled the whole football community.
Enough money was raised online to allow Sala's family to fund a private search after an official rescue operation for the light aircraft was called off. Authorities said there were unlikely to be any survivors.