KANSAS CITY, Mo. -- It's been a half-dozen years of push and pull over how, and whether, to save an endangered fish in the Missouri River.

Finally, sometime this summer, work will begin on a project to create more habitat for the pallid sturgeon near Arrow Rock, Mo.

"We're ready to move on," said Zach White, project manager for Jameson Island of the Army Corps of Engineers.

Plans have been underway for decades to save the dinosaurlike bottom-feeder, because dams and other changes to the river have steadily destroyed its habitat. Young pallid sturgeon need shallow, murky, slow-moving water to survive.

But in 2007, the corps stopped work on its Jameson Island habitat restoration project to address questions raised by environmentalists and farmers.

To create the shallow, muddy waters for the sturgeon, the corps planned to dredge soil from the banks of the Missouri and spit it into a new branch of water habitat off of the river.

But there's phosphorus in the soil, and eventually that soil would reach the Gulf of Mexico, perhaps worsening a hypoxic zone in the Gulf where oxygen-depleted water makes it difficult to support aquatic life.

Farm interests in the Midwest have been under pressure for years to limit what they put into the soil, which subsequently ends up in the Missouri River. Phosphorus levels in the waterway often get blamed on farmers. So in 2007, they fought the corps' project.

"The Missouri River is responsible for 20 percent of the phosphorus that gets into the Gulf of Mexico. This project will double that amount," said Bob Perry of Perry Agricultural Laboratory Inc. in Bowling Green, Mo.

"There are all sorts of other things they could do if they put their mind to it."

Perry said he is not against efforts to create habitat for the sturgeon. Rather, he'd prefer the corpsfind a way other than "soil dumping."

The Missouri Clean Water Commission asked to delay the project until the corps could prove the dredging method wasn't pumping a bigger problem into the Gulf.

The corps solicited the help of the National Academy of Sciences. Members of the academy did a study that determined that, indeed, the entire Missouri River is responsible for 17 to 20 percent of the phosphorus in the Gulf.

But the academy also found that the Jameson Island initiative will not have a significant impact on the hypoxic zone, White said.

The study said that within a year's time, the Jameson Island work would account for at most 1 to 2 percent of the phosphorous in the Gulf of Mexico, and that's in the unlikely event that all the dredged soil ends up there.

The work near Arrow Rock is part of a larger corps effort to create 20 to 30 acres per mile of shallow water habitat all along the Missouri River.

The National Academy of Sciences said that all of the shallow water habitats created by the corps so far account for 6 to 12 percent of the phosphorus in the Gulf.

Now, with the project cleared to go, White said he expects excavation of the Jameson Island site will start sometime this summer.

The project, estimated at $3.5 million, could take up to a year, depending on weather.

When it is complete, the pallid sturgeon will have a mile-long, man-made branch full of slow-moving water where their young can thrive.

That pleases people like Jane Ledwin and Tracy Hill.

They say ensuring the survival of the species is important because it is a puzzle piece to a much larger, connected environment.

"It would be incredibly unwise for us to assume any species is expendable," said Ledwin, a biologist with the U.S. Fish and Wildlife Service.

Besides, Ledwin said, the habitat project is important not just for the pallid sturgeon but for other fish in need of places to spawn. Water fowl and birds of prey will also thrive there.

"This has great potential to be a really rich environment," she said.

As for the pallid sturgeon, a 70-million-year-old relic, there are, well, prettier fish.

They look a bit like dinosaurs or sharks with lengthwise rows of bony plates instead of scales, flattened snouts and long slender tails. They can grow 6 feet long and weigh 80 pounds.

These fish have no teeth, but can suck small fish and invertebrates from the river bottom. And like other ancient fish, one federal agency said, pallid sturgeon have a skeleton of cartilage rather than bones.

They can live as long as 50 years.

The pallid sturgeon was declared endangered in 1990, so it's illegal to kill them. Before 1990, they were popular with fishermen. Their eggs could be used as caviar, though most caviar came from other species.

Hill, project leader for the Columbia Fish and Wildlife Conservation office, doesn't think the pallid sturgeon is ugly in the slightest.

"Beauty's in the eye of the beholder," he said.