The tiny Nooksack dace lives in only four streams on the Lower Mainland of B.C. (Mike Pearson/Ecojustice)

Environmentalists say they have won an important legal victory to protect endangered species across Canada, all because of a tiny fish known as the Nooksack dace, an endangered species no more than 15 centimetres long.

In the ruling issued Wednesday, the Federal Court admonished the fisheries and oceans minister for failing to identify the habitat of the Nooksack dace, which lives in only four streams in B.C.'s Lower Mainland.

According to the coalition of environmental groups that launched the lawsuit, the precedent-setting legal victory for endangered species may put an end to years of unlawful action by the federal government.

"We are ecstatic about the ruling," said Christianne Wilhelmson of the Georgia Strait Alliance. "We hope that DFO will now start giving real protection to endangered plants and animals without having to be dragged into court for every species it is supposed to protect. Canadians owe a lot to this little minnow and to the scientists who stood up for it."

"This case is not only a tremendous victory for the dace, but for Canadian species everywhere that have been left unprotected by the act," said Rachel Plotkin of the David Suzuki Foundation.

In his judgment, Justice Campbell said the lawsuit, brought by Ecojustice lawyers on behalf of the David Suzuki Foundation, Environmental Defence, Georgia Strait Alliance and the Wilderness Committee, was "absolutely necessary."

He described the case as "a story about the creation and application of policy by the minister in clear contravention of the law, and a reluctance to be held accountable for failure to follow the law."

That law, the Species at Risk Act, requires the federal government to identify the critical habitat of endangered and threatened species. The environmental groups' lawsuit was filed in 2007 after the DFO unlawfully deleted habitat maps from the Nooksack dace recovery strategy.

"We are putting DFO on formal notice that it has 90 days to rewrite B.C. species' recovery strategies that have unlawfully failed to identify critical habitat," said Ecojustice lawyer Lara Tessaro.