Alastair Salvesen, scion of the Christian Salvesen shipping empire, approached locals to ask for support for the 10-pen fish farm in picturesque Loch Etive, near Oban, which campaigners fear will destroy a celebrated landscape and wildlife.
The move by Mr Salvesen, owner of fish farming firm Dawnfresh, sparked controversy among some residents.
A total of 617 objections and 221 messages of support have been lodged about the proposal and Argyll and Bute Council will make a final decision in January.
However, Richard Kerr, senior development control officer at the council, has recommended the plans be granted approval.
Iain MacDonald, who lives near Ardchattan, was a member of the Argyll and Bute planning committee when he received a visit from Mr Salvesen.
He said: "He called at my house unannounced over the summer. I would normally be impressed if people at that kind of level went around speaking to individuals, but it depends how you take the approach.
"He was with a regional director making courtesy calls to what he called 'prominent members of the community'. He appeared in a top of the range black Range Rover, with blacked out windows. They came out the car with black suits and black coats on, so it was quite an impression.
"If I was an wee old lady I would consider it inappropriate if two guys in suits came to the door and started talking about something like that. It put me in a very difficult position because I was on the planning committee and I made it clear I could not discuss matters to do with the application."
He added: "Perhaps Dawnfresh should handle an application of such sensitivity a bit better."
Taynuilt Community Council had objected to the plans and expressed concerns about the visual impact. It now supports the move, saying the "employment Dawnfresh has brought to an economically fragile area is significant and the economic and employment contribution this additional development can make to the area is the most important issue".
It sparked claims by the Friends of Loch Etive (Fole) group, which has been campaigning against the farm, that there was a conflict of interest as a donation was made to Taynuilt Sports Council by a charitable trust owned by Mr Salveson as part of a fundraising campaign for a new pavilion.
Fole has reported the community council to the Commissioner for Ethical Standards in Public Life in Scotland, saying David Thomson, who sits on both the community council and the sports council, should have declared an interest when discussing the plans. It says the council has not adequately explained its change of heart.
Mr Thomson said the issue of whether or not to declare an interest was discussed but it was felt unnecessary to do so. He said: "The donation was nothing to do with Dawnfresh. It was to do with Mr Salvesen's charity. The donation was not a secret."
The Salmon and Trout Association Scotland and the Argyll and District Salmon Fishery Board fear the plans would threaten the River Awe's salmon stock. They say there would be issues with escapes and the large and voracious alien trout would eat juvenile salmon, depleting the stocks of the native fish. They said they were also concerned about disease transmission.
A spokesman for the fishery board said: "Salmon angling in the Awe catchment is of significant economic value to the area in terms of direct income and indirect benefit, and the catching of escaped rainbow trout poses a reputational risk to this prime salmon fishery."
A Marine Scotland Science spokesman said: "Escapes pose a risk to wild species due to competition and disease although proposed containment and escape contingency measures are acceptable."
Nobody at Dawnfresh was available for comment.