BILLINGS, Mont. (AP) — Wildlife advocates claimed in a federal lawsuit filed Monday that the dinosaur-like pallid sturgeon could be wiped out in stretches of rivers in Montana and North Dakota if the federal government doesn't deal with dams that disrupt spawning.
Pallid sturgeon are known for their distinctive shovel-shaped snout and can live 50 years, reaching 6 feet in length.
Believed to date to the days when Tyrannosaurus Rex walked the Earth, the species has declined sharply over the past century as dams were built along the Missouri River system.
In a lawsuit, attorneys for Defenders of Wildlife and the Natural Resources Defense Council asked a judge to order new steps to protect the last 125 pallid sturgeon downstream of Fort Peck Dam in Montana to Lake Sakakawea in North Dakota. That includes fish on the lower Yellowstone River.
The groups say Fort Peck Dam and a smaller dam on the Yellowstone River near Glendive prevent sturgeon from successfully breeding.
The three defendants named in the lawsuit — the U.S. Army Corps of Engineers, Bureau of Reclamation and Fish and Wildlife Service — are considering modifications to the Yellowstone River dam to allow sturgeon to pass around it.
Army Corps spokeswoman Michael Coffey said an environmental study of the proposed Yellowstone dam modifications was close to being finalized.
Federal officials have said the $59 million upgrade to the dam would allow sturgeon access to an additional 165 miles of the river for migration and spawning.
The lawsuit, however, claims the agencies' plans would result in a larger dam and creation of an artificial side channel that sturgeon won't necessarily use.
"It's one of those twisted tales of some good intentions but in the end the outcome is this monster project that a lot of the experts we are talking to have serious concerns about," said Steve Forrest with Defenders of Wildlife.
Without the channel, sturgeon on the Yellowstone have been left to wait for high waters to form a natural passage that lets them get around the dam. Most years that passage is not available.
Federal officials have said rebuilding the dam and constructing a side channel offers the best chance for fish to get further up the Yellowstone. But they still are uncertain how well it will actually work, due to limited information on whether pallid sturgeon are willing to use such routes.
The intake dam was built beginning in 1905 to provide irrigation water for almost 400 farms covering more than 54,000 acres of land in eastern Montana and western North Dakota.
The lawsuit also claims water releases from Fort Peck dam are killing off young sturgeon in the Missouri River.
Pallid sturgeon was listed as an endangered species in 1990. Its numbers have since increased, according to federal scientists, but the precise size of the population remains unknown.