The growing realization that southern resident orcas are starving to death has led green groups to urge stronger measures to save them.

The David Suzuki Foundation and the Raincoast Conservation Foundation have called for an immediate closure of fishing for chinook salmon on B.C.'s coast.

Orcas rely on chinook to survive and it's their preferred prey.

The demand for a ban on chinook fishing comes after a female southern resident orca captured attention around the world for keeping her dead calf above the water for 17 days.

“If an orca mother’s prolonged display of grief and signs of starvation among J-pod don’t inspire action, what will?" asked the David Suzuki Foundation's Jay Ritchlin in a news release. "We’re in a crisis situation that requires an emergency response."

Raincoast Conservation Foundation biologist and wild salmon director Misty MacDuffee said that closing the chinook salmon fishery is the orcas' "best chance of survival".

Under the Pacific Salmon Treaty, up to two million chinook are caught each year on both sides of the border.

According to the environmental groups, the southern resident orca population requires about 1,400 chinook each day to remain alive.

They say that chinook fishing that should only be permitted "outside of the range of the whales and closer to spawning grounds that can demonstrate they are meeting biologically defined wild Chinook escapement targets".

Last month, North Vancouver MP Jonathan Wilkinson became the new fisheries minister.

In June, the federal government promised "key actions" to help the species, including improving the availability of prey and reducing the noise of vessels.

According to the Orca Network website, there are 75 southern resident orcas in four separate pods. The last one was born in 2015.

The David Suzuki Foundation and the Raincoast Conservation Foundation are also calling for the shutdown of commercial and recreational whale-watching targeting endangered southern resident orcas.

“New distance regulations don’t go far enough to limit disturbance to these whales as they forage for prey," Ritchlin stated. "We must limit vessel disturbance so there’s a possibility that future generations will also be able to experience these whales."