Laura Lundquist

(CN) — When it refused to protect the arctic grayling in Montana, the U.S. Fish and Wildlife Service ignored the best available science and made too many assumptions about voluntary conservation efforts, according to a new lawsuit from conservationists.

On Monday, in Butte, Montana, federal court, environmental groups sued U.S. Interior Secretary Deb Haaland and the U.S. Fish and Wildlife Service in yet another challenge of the service’s decision not to list a Montana population of arctic grayling.

The lawsuit is in response to the service’s July 2020 finding that arctic grayling in Montana don’t require protection. It’s the fifth challenge of various decisions going back to a 1991 petition to list the species and its 1982 finding that arctic grayling warranted listing.

Arctic grayling are a remnant of the glacial age, an iridescent cold-water trout with a distinctive sail-like dorsal fin. While they still live in Arctic Ocean tributaries of Alaska and northern Canada, fewer populations have persisted in the lower 48 states, and fewer still are adapted to living in rivers. Most reside in lakes, including those that have been stocked in lakes of several Western states, and they tend to do poorly if transplanted into rivers.

South of Canada, the only river-adapted populations live in Montana in two rivers of the high headwaters of the Missouri River. Because of that, the Fish and Wildlife Service designated Montana’s grayling as a distinct population segment of the species in 2010, potentially worthy of its own protection because “preservation of the breadth of the known arctic grayling life history spectrum is warranted.”

The populations in both rivers are small and have long been challenged by the loss of habitat and fragmentation due to dams. The population in the Ruby River was reintroduced using fish from the Big Hole River, but it’s struggled to do more than persist.

Earthjustice attorneys representing the Center for Biological Diversity, Western Watersheds Project and Butte resident Pat Munday cite a handful of reasons as to why the U.S. Fish and Wildlife Service’s decision was arbitrary and unlawful under the Endangered Species Act.

The service said landowner efforts had improved some aspects of streamflow and riparian habitat and went on to say those characteristics would improve as more landowners joined in.

Big Hole area ranchers, led by rancher Cal Erb, tried to stave off the restrictions that would accompany a federal listing by agreeing in 2004 to make fish-friendly improvements using a new voluntary option called Candidate Conservation Agreement with Assurances. The Fish and Wildlife Service created the option in 1999 to provide incentives for landowners to engage in active conservation of sensitive species.

But the lawsuit says those voluntary conservation efforts don’t go far enough as the “regulatory mechanisms” that a listing would require. In addition, Fish and Wildlife didn’t conduct any analysis “to assure the requisite level of certainty that such efforts will actually be implemented” as required by a 2003 policy, the lawsuit said. And finally, the service couldn’t use predictions of future volunteer work to justify not acting now, according to the conservationists.

“Voluntary measures haven’t recovered the grayling and are not enough to bring this unique fish back from the brink of extinction,” said Erik Molvar, Western Watersheds Project executive director. “The compounding threats of irrigation withdrawals, livestock degradation of key spawning streams, and climate change warrant bold federal action to protect the grayling’s last remaining strongholds.”

The service also ignored the effects of small population sizes — effectively 200 to 300 breeding fish in the Big Hole — and climate change, the nonprofits say.

Water temperatures in the Big Hole River and its tributaries are already rising and climate change will cause the region to continue to get hotter and drier. As irrigators continue to pull water out of the river, that also causes the water temperature to rise.

The Big Hole Watershed Committee formed to coordinate landowner efforts but drought plans still allow irrigators to pull some water out of the river, leaving stream levels dangerously low at times. About 90% of the grayling live in streams bounded by private land.

Finally, the plaintiffs say the service assumed that grayling could escape water that was too warm by swimming to cooler water called “thermal refugia.” They claim the service did no research to prove this was the case and offer evidence that barriers — physical and thermal — often keep fish from being able to move.

The conservationists say Fish and Wildlife “cherry-picked data” to support its decision not to list while ignoring other data showing “that conditions in the Big Hole River are going to severely decline with climate change, that thermal barriers could impact the grayling’s ability to reach refugia, and that there is considerable uncertainty about whether the fish will be able to adapt and survive.”

In a statement, Earthjustice attorney Emily Qiu said, “These fish face a litany of threats including over-withdrawal of water, habitat degradation, competition from non-native fish, and now climate change on top of it all. Too much water is already taken out of the Big Hole River and climate change will only make the situation worse.”

The conservationists want a judge to vacate Fish and Wildlife's 2020 finding and order the agency to review the decision.