The legal battle over a five-storey tidal turbine lowered into the Minas Passage last fall opened Wednesday in a Halifax courtroom as a fishermen's group urged a judge to revoke the project's approval.

The lawyer for the Bay of Fundy Inshore Fishermen's Association argued in Nova Scotia Supreme Court that the province's environment minister granted approval of the project without gathering enough environmental data.

David Coles said operators of the turbines failed to produce "relevant baseline data." That data, he said, is a snapshot of the environmental state of the Bay of Fundy before the turbine was deployed.

Without the information, it is impossible for the Department of Environment or the federal Department of Fisheries and Oceans measure what effect the turbine may have on fish or sea mammals.

"The baseline is necessary to compare harm," Coles told Nova Scotia Supreme Court Justice Heather Robertson.

Project manager disputes claim

The turbine is owned by Cape Sharp Tidal Ventures, while the non-profit Fundy Ocean Research Centre for Energy (FORCE) is managing the test site in the Minas Passage.

Outside court, FORCE spokesman Matthew Lumley called Coles's claim a "false argument." He said FORCE believes it's impossible to establish a baseline snapshot of pre-turbine conditions in the Bay of Fundy because the area changes with every tide.

Tony Wright, the general manager of FORCE, said the size of the turbine must be considered.

"We're talking about one turbine in the Minas Passage. It represents less than 0.1 per cent of the cross sectional area of the Minas Passage," he said.

"So any effects that the turbine might have on the environment are expected to be negligible."

'Learn by doing'

Wright said the goal of the turbine trial is good for the environment — to help Nova Scotia become less dependent on fossil fuels.

"And the only way we're really going to learn anything about whether this can be a potential option for Nova Scotia is to learn by doing," he said.

FORCE has previously said in court documents that it disagrees with the fishermen's claims that the tidal turbine would cause a decline in the commercial fishery across the entire region.

The Environment Department is the regulator that approves the plan.

The lawyer for the department, Sean Foreman, told Robertson the fishermen's association was suggesting she should stray into acting as "an arbiter of science" and not an interpreter of the law.

Two days have been set aside for arguments in Nova Scotia Supreme Court.

The fishermen's group sought an injunction in October to stop the deployment of the turbine, but a judge refused to grant that request. The turbine was deployed Nov. 7.