RIVERDALE - The Garrison Dam National Fish Hatchery was well on its way toward breaking all previous production records for walleye, but success tapered off a bit last week. The North Dakota Game and Fish Department requested that the hatchery raise more than 8 million walleyes for stocking into state lakes in 2012.
A lot has to go right to get to that lofty total, but this year showed promise of looking more and more like one for the record books. The most walleyes the Garrison hatchery had produced previously in a single season was 10 million.
"If everything hits right we can get to that point," said Rob Holm, hatchery project manager. "This year it looks like everything is hitting right."
A holding tank containing tiny shovelnose sturgeon is observed by Rob Holm, Garrison Dam National Fish Hatchery project leader. The shovelnose will be shipped to Wyoming.
The eyes can be seen in these cutthroat trout eggs incubating at the Garrison Dam National Fish Hatchery. When large enough, the cutthroats will be released into the Missouri River.
Holm made the comment shortly after collecting samples of small walleyes from several outdoor rearing ponds and before fish in all the ponds reached stocking size. The stomach contents of the tiny walleyes would be examined later inside the hatchery's main building. Some of the ponds had already had their walleyes removed and trucked to state lakes to be released.
According to Holm, the young-of-the-year walleyes were among the healthiest in memory. The biologist speculated that last year's high water was possibly responsible for better walleye growth in the hatchery's outdoor ponds this summer. Missouri River water was used to fill the outdoor ponds where the young walleyes were placed after hatching under closely regulated conditions inside the hatchery.
"There is a difference in fertility. We've had a lot of midges, which are the primary food source of the walleyes after about the second week," said Holm. "The ponds have had great zoa plankton production, the result of a new connection to the Missouri. We're taking a look at it."
The standard survival rate for young walleyes in the hatchery's outdoor rearing ponds is 50 percent. Approximately 250,000 fry are released into each holding pond with the hope of 125,000 reaching fingerling size. It doesn't always work out that way.
"Sometimes a pond will be a bust and you get nothing back," said Holm. "That's just the way pond production works. We're relying on Mother Nature in a lot of cases. Right now we're running about 70 percent, which is great."
A later tally showed that survival in the final few walleye rearing ponds had slipped a bit and the overall total would be less than what was originally hoped. Biologist Jerry Tishmack estimated the drop to 60 percent, still considered very good.
"It was falling off a bit this week," said Tishmack this past Tuesday. "We've stocked out 7.8 million and still have a half million left."
That means the Garrison hatchery surpassed the state request of 8 million young walleyes, but came in below their previous record.
400 pound fish?
At the USFWS Valley City National Fish Hatchery space is being set aside for a project that could result in some colossal fish stories coming out of the Red River in future years. Biologists are hoping to discover the key to returning a population of lake sturgeon into the Red.
Lake sturgeon are present in the Rainy River, which forms a portion of the border between Minnesota and Ontario. Adult lake sturgeon are known to push the scale to 400 pounds.
"A process is in place to restore that Rainy River strain into the Red River," said Holm. "We are trying to get that thing going again. We talked to the DNR in Wisconsin, Minnesota and Manitoba. We're just going to see what we can do to help out."
A positive for the possible return of lake sturgeon in the Red River is the recent removal of several low-head dams on the Red. The dams had previously blocked passage of sturgeon up river. Before any meaningful stocking can occur, biologists must first discover the best method of raising lake sturgeon in a hatchery environment.
"There was a lack of space, basically, in the facilities in which they are currently trying to raise them in Wisconsin," explained Holm. "We've got buildings for it at Valley City, but not the manpower. We just moved sturgeon from Garrison to Valley City. It is a different strain of lake sturgeon, eggs we obtained from Canada, more or less for research so we can get the process down. We'll find out what our capabilities are. We're wanting to get our foothold in some of these programs that the service feels are high priority."
Are mussels in North Dakota in trouble? No one really knows the answer to that question, but USFWS biologists have been asked to do some research on the subject.
"Mussels are something that have been on our list to do as a service for many years," remarked Holm. "We know that mussels throughout the U.S. are in jeopardy with habitat degradation, pollution and Aquatic Nuisance Species."
The Sheyenne River is considered the "hotbed" of mussels in North Dakota, bearing the bulk of the state's mussel population. If the Sheyenne continues to receive increased flows from Devils Lake, the mussels could be affected.
"Today they are more or less an indicator species. They are a filter feeder," said Holm.
Biologists have recovered a number of mussels and placed them in the Valley City hatchery. The hatchery utilizes water from the Sheyenne River, which will flow right through hatchery troughs containing North Dakota mussels. Then it is just a matter of studying any changes that might occur.
"We'll see how they do. Perhaps we can colonize some areas where they were extirpated through drought, which has a big impact on these critters," said Holm.
Although nearly 300 kinds of freshwater mussels live in U.S. waters, it is estimated that 70 percent of freshwater mussels are extinct or in danger of becoming extinct.
While the endangered pallid sturgeon has been receiving plenty of attention in North Dakota elsewhere, its cousin, the shovelnose, is also in need of help. The biggest concern for shovelnose may be in Wyoming where populations have been on the decline and in need of a boost.
In a cooperative effort with Wyoming, a former feed storage room at the Garrison hatchery has been converted into an incubator for shovelnose sturgeon. Several hundred shovelnose were recently hatched at the Garrison facility and are doing well inside holding tanks supplied by Wyoming.
"It is a hit and miss thing, but when we can produce shovelnose, we do," said Holm. "We rely on Montana to collect brood stock from the Powder River and spawn them at Miles City."
As part of the continuing relationship with the state of Wyoming, the Garrison hatchery periodically receives cutthroat trout eggs. A recent shipment of cutthroat eggs are due to hatch soon at the hatchery. Approximately 20,000 cutthroats will be kept indoors until ready for release into the Missouri River in 2013.
Cutthroat have been a nice addition to the Missouri River fishery. The state record of 10 pounds, 1 ounce, was taken from the Garrison Dam Tailrace in 2003.