That is the view of Highlands and Islands Green MSP John Finnie, who has been campaigning to stop the proposal and has pressed the Scottish government for details of the dangers posed by the oil transfers.
The pod of six orcas, including a new-born calf, is known as the Northern Isles community. The family migrates between Iceland and the Moray Firth each year, and would be vulnerable to any oil spill in the firth resulting from ship-to-ship transfer operations.
Mr Finnie urged the new minister for environment, climate change and land reform, Roseanna Cunningham, to make the Scottish government’s position clear.
Cromarty Firth Port Authority has applied for a licence for the risky ship-to-ship procedure, in which oil is transferred between vessels in the open sea rather than secured in a harbour. The application is presently being considered by the UK’s Maritime and Coastguard Agency.
Mr Finnie said the Scottish Greens had a strong track record in protecting coastal communities from ship-to-ship plans.
A three-year campaign by Green MSPs to halt similar plans in the Firth of Forth ended in victory when Forth Ports PLC dropped their proposal in 2008.
Mr Finnie launched the Save Our Dolphins campaign in response to the Moray Firth plan in January this year, his petition receiving over 3,700 signatures.
He said: “The orcas are a highlight of Shetland’s spectacular marine life. They help bring visitors to the islands, and joy to the islanders.
“It’s terrible to think of these extraordinary animals being put in danger for the sake of unnecessary ship-to-ship oil transfers in the Moray Firth.
“Oil transfers are already carried out safely in the relative shelter of Nigg harbour; there’s no need to take chances with risky ship-to-ship operations in the open sea.
“I’m trying to find out whether the Scottish government understands the threat to Shetland’s orcas, and to the wider marine environment.
“If it does, I hope new environment minister Roseanna Cunningham will break the silence that her predecessor inexplicably maintained on the issue, and join the opposition to the proposal.
“Green MSPs have beaten ship-to-ship plans once before, in the Firth of Forth. With your help we can do it again: please sign the petition at http://bit.ly/SaveOurDolphins.”