Biologists plan to tag 7,000 young, endangered pallid sturgeon, starting next week with a first wave of more than 4,600 of the 4½- to 5-inch fish.

Shortly after that, the pallids will be stocked in the Missouri River above Lake Sakakawea, said Rob Holm, the project leader at the Garrison Dam National Fish Hatchery in Riverdale.

"Part of them will go in the Yellowstone River and more in the Missouri River as far up as the Milk River, right below Fort Peck Dam," Holm said Tuesday.

The planned two-day tagging effort will involve three four-person crews, with three people applying a tag apiece and the other person shuffling fish and recording data about the prehistoric-looking pallids.

After a first-day tune-up, Holm expects each crew will tag 1,000 pallids on the second day.

"We should be able to whip through them in fairly good time," Holm said.

Each pallid will receive two different colored elastomer tags and one coated wire tag.

A blue elastomer tag will identify the pallids' year class, and a variety of other colors will identify the area where the pallid was released.

The tags provide key information when pallids are netted in future years, Holm said.

"The tags tell us it was stocked at, say, Culbertson (Mont.) and is now upstream or downstream from there," he explained. "If we have a good stocking site, we have more fish surviving in those groups. It keys us on which sites are good and which river systems work best."

The hatchery is holding three batches of young pallids, some spawned in Riverdale and two other bunches that were spawned in hatcheries in Yankton, S.D., and Miles City, Mont.

"We are trying to ensure family diversity and avoid brother-sister matings," Holm said.

Holm still is awaiting a go-ahead from the U.S. Fish and Wildlife Service's Bozeman Fish Health Center in Montana before starting the tagging project, which is scheduled for Monday and Tuesday.

"We're anticipating no negatives. The fish are looking good with no problems health-wise. We're assuming it's a go," he said.

The rest of the 7,000 pallids will be tagged about three weeks later, Holm said.

He also will hold about 4,700 pallids over the winter, then tag and stock them in April.

"We'll let them get a little larger," he said, explaining that larger pallids can be tagged with a passive integrated transponder, or PIT, tag that has a unique 10-digit code and allows researchers to scan the netted pallid to retrieve key information.

Pallid sturgeon are listed as endangered species, and fewer than 200 are believed to exist in the upper Missouri River system. The spawning, tagging and stocking projects are designed to supplement the population.

(Reach reporter Richard Hinton at 250-8256 or richard.hinton@;bismarcktribune.com.)