VANCOUVER - Indigenous groups in Canada and the United States are calling for a study of how human activity has degraded the waters off British Columbia's coast before any new vessel traffic is allowed in the area, where port and pipeline activities are on the rise.

Members of the Tsleil-Waututh Nation in B.C. and the Tulalip Tribes and Lummi Nation in Washington state say they want a halt to any more marine traffic in the Salish Sea until the impact study is complete.

"We're Coast Salish nations that have come together from both sides of the border with the United States and Canada to address this urgent issue that's happening to our Salish Sea," Raynell Morris of the Lummi Nation said Wednesday.

They say the proposed Trans Mountain pipeline expansion and a new shipping terminal at Roberts Bank, 35 kilometres south of Vancouver, would increase pressure on sea life.

The Federal Court of Appeal quashed the Trans Mountain project's approval in August in part due to the National Energy Board's failure to consider marine shipping impacts.

Rueben George of the Tsleil-Waututh said the decline of salmon stocks and, in turn, the endangered southern resident killer whales should be a wake up call to politicians on both sides of the border.

"To me it's like the canary in mines. The animals are going and it's happening and it's not going to be too long before it's affecting all of us," George said.

The groups said fisheries, sacred sites and traditional economies are all threatened by new and expanding port facilities and they want the study to consider change over time, not just the impacts of a single project.

They suggest establishing a baseline for Salish Sea health at 1985, when harvest levels were still considered healthy. The Lummi Nation also wants to meet with federal Environment Minister Catherine McKenna on the topic, Morris said.

The groups did not rule out demonstrations if U.S. and Canadian authorities refuse to conduct a study, with Morris saying they would protect the land and sea "by any means available and possible and necessary."

Fisheries and Oceans Canada and Environment and Climate Change Canada did not immediately respond to requests for comment.

The Indigenous representatives spoke during a break at an information session held by the Canadian Environmental Assessment Agency's review panel on the proposed Roberts Bank Terminal 2 project.

The project, proposed by the Vancouver Fraser Port Authority, would see the construction of a new three-berth marine container terminal in the waters off Delta.

Cliff Stewart, vice-president of infrastructure for the port authority, said demand has been increasing on Canada's west coast for all types of shipping over the past couple of decades. The average growth in demand for container volume alone increases eight per cent each year, he said, which is why the port authority proposed building the new terminal.

Long term forecasting says growth will decline to four or five per cent over the next five to seven years, then down to about three per cent each year over the next several decades.

"But given the volume that now is coming in through the west coast, even a three per cent growth is a significant amount of containers each year," he said.

Existing infrastructure can be expanded but even then it is projected to reach capacity by the mid-2020s.

Any new project that requires an environmental assessment by the Canadian Environmental Assessment Agency has a consideration of cumulative effects built in, Stewart said.

"The way that environmental assessment methodology works is you look at the impact of a particular project and if there are residual impacts after mitigation, then you have to look at the cumulative effects of that particular effect," Stewart said.

In the case of Roberts Bank Terminal 2, the only new projected impact after mitigation is an increase in underwater noise, which would have a negative effect on the southern resident killer whales, he said.