MONTREAL -- A judge has suspended exploratory drilling for the TransCanada oil terminal in eastern Quebec after objections by environmentalists.

The decision by Quebec Superior Court Justice Claudine Roy to grant a temporary injunction on Tuesday stops the Alberta-based company from conducting seismic surveys in Cacouna until Oct. 15.

That work involved studying the composition of the sea bed in that part of the Lower St. Lawrence to determine where the port could be built.

The marine terminal would allow TransCanada (TSX:TRP) to export oil transported from the Alberta oilsands as part of its Energy East pipeline project, which has been submitted to the National Energy Board.

It is estimated that the equivalent of one million barrels of crude oil would be transported daily through the 4,600-kilometre pipeline to refineries and terminals in Quebec and New Brunswick.

TransCanada says Quebec could get tax revenues of more than $2 billion by combining the design and construction phase as well as operation of the pipeline.

According to the ruling, Quebec's Environment Department authorized the drilling without obtaining the answers it was seeking from Fisheries and Oceans Canada.

"If the minister did not get the answers to his questions, he should have continued the process or at least explained why he suddenly decided to recommend approval," the judge wrote.

She also noted that "TransCanada provided no specific information on the impact of a suspension of work for that period, other than an economic hardship."

The judge acknowledged it is "unfortunate" the company suffers the consequences of a "perceived deficiency" in the approval process but added she is making her ruling because an endangered species is involved.

Roy also criticized Environment Minister David Heurtel, suggesting he had not fullfilled his mandate.

"According to the law on environmental quality, the minister, before giving approval, must ensure that the emission of contaminants into the environment will be in accordance with the law and regulations," she wrote.

The decision also pointed out that TransCanada filed its application on May 26 and has refused to sign an assurance that its work will not harm the whales.

The four environment groups that petitioned the court wanted work suspended during a period they believe is critical for beluga mothers and their calves in the region.

Documents filed by lawyers for the environmentalists alleged that the Quebec and federal governments ignored expert advice about the belugas.

TransCanada has argued it had all the proper permits and was sensitive to the belugas in the area.

Greenpeace spokesman Patrick Bonin said drilling could resume after Oct. 15 but that TransCanada's permit is valid until November.

"Belugas start to leave the area around the 15th," he said.

He added that environmentalists would like to cancel the permits for the drilling and that hearings on that could begin in February.

TransCanada said in a statement Tuesday it is studying the court judgment and that it obtained all the necessary approval and permits to proceed with the work.