Several agencies teamed up at the Neosho National Fish Hatchery this week to give endangered pallid sturgeon a better chance for survival.
The team tagged and recorded data for six family lots of 1,325 each or 7,950 fish. Workers started the process Monday afternoon and wrapped things up Tuesday afternoon.
The fish will be stocked next week in the Missouri River at nursery sites, where the fish will hopefully return to spawn on their own.
Four work stations sorted fish for their final destinations: Atchison Kan., between St. Joseph and Kansas City; Lexington, Mo., east of Kansas City; Ponca, Neb., near the South Dakota and Nebraska border and Nebraska City, Neb., near the Nebraska, Iowa border. The fish, divided by family lots, were collected, inserted with a Passive Integrated Transponder tag, then scanned and their length and weight recorded. The family lots were mixed as the fish were put into tanks according to destination.
“When we work together it’s wonderful what we can accomplish,” said Neosho National Fish Hatchery Manger Dave Hendrix. “It takes all these different teams to make it happen.”
A large contingent of the team came from Nebraska Game and Parks Commission, but one came from Blind Pony State Fish Hatchery, and others came from the US Fish and Wildlife Service, the Columbia, Mo. office of the US Geological Survey and the Chillicothe office of the Missouri Department of Conservation making for a team of 28.
Data will be stored under the 10-digit alphanumeric code assigned to each fish. Every spring a large effort goes into capturing mature adults with 30,000 to 40,000 hooks on the Missouri River. When tagged fish are caught how far they have traveled from the stocking site, their weight and length is updated and that information helps scientists form a picture of the sturgeon population.
“The benefits from the stocking program are starting to show,” said Kirk Steffensen, fisheries biologist with the Nebraska Game and Parks Commission.
Now approximately 75 percent of the fish they catch every spring are hatchery reared.
So they know releasing the sturgeon is a successful effort, and they know the fish are spawning, but so far there is no measure of how successful those spawns have been.
The backup system for the $4 tags is to remove one of the scutes, spiny protrusions that run in a double row down the fish’s back. The fish going out next week had their fifth left scute removed – marking them as May 2009 spawn – next year the mark will be on the right.
“We can over winter them here,” said Rod May, assistant manager at the Neosho hatchery. “We’ll take the fish that would normally be stocked in the river at a smaller size.”
The sturgeon would have been four or maybe five inches long last fall, but they are 10 to 14 inches now. More of the fish survive at the larger size.
The pallid sturgeons are top-level predators, as the river was channeled and developed their numbers dropped. They are an indicator fish for ecosystem balance and scientists worried the their numbers were so low they would never recover. In the mid-1990s they began stocking the river. A male pallid sturgeon will not mature until it is six to eight years old, a female at eight or even 10 years old. Pallid sturgeon may range 400 to 500 miles on the river.
When an unmarked pallid sturgeon is caught it gets a genetic test before it is used for breeding stock. If the bloodline is clear scientists map out breeding pairs to give the hatchery the most diverse stock.
“Their genetic plan makes us stock these fish in the area where their parents were caught,” Steffensen said.
Last year Neosho thought they had several female pallid sturgeons, but it turned out to be hybrids after the test.
Steffensen said there is tremendous effort and teamwork put into rebuilding pallid sturgeon stock from the fishing in the spring to coordinating field crews with the hatcheries. He is usually out in the field and says his job is easy compared to some of the work that goes on in the hatcheries.
“These fish don’t always spawn from 8 to 5,” Steffensen said.
It is a long process to breed pallid sturgeon, May said. They have to sample the eggs, boil them in a beaker, cool them on ice and then slice through an egg. Under a microscope they check to see if the nucleus is migrating to the animal pole – an unusual step that makes working with sturgeon eggs almost like working with a mammal. Fertilize the eggs too soon and they will have no fish, fertilize the eggs too late and the same result.
“There’s a window there that we have to hit or our year’s work is gone,” May said.
Males get one injection of hormone and the females two before they have to start checking them once an hour to see if they’re ready to spawn. They only get so many eggs for each collection and they have to be harvested repeatedly every hour in a process that can stretch for a full day.
Hosting the tagging session was a pleasure for May.
“A lot of times the guys who work in the river don’t see our end of it and we don’t see their end of it,” he said. “They get to see results of their work and see the hatchery environment.”
The whole project, he said, is a team effort from up and down the Missouri River.
“We’re all in this together,” May said.
“We don’t all wear the same patch, but we all have the same common end goal and that is all about the pallid sturgeon.”