Minnows vs. midges: A new way to fight wildlife disease

Last year, Mike Penfold was hunting on the Marias River in north-central Montana. On his float down the river, the former state director of the Bureau of Land Management saw only one live white-tailed deer.

“But there were so many dead ones,” he said.

They were easy to see because the deer have been ravaged by epizootic hemorrhagic disease, or EHD, which causes severe hemorrhaging and high fever, prompting afflicted animals to seek water for drinking or immersion.

On one leg of the hunting trip, Penfold saw the carcasses of four or five white-tailed deer on the riverbank.

“That kind of got my attention,” he said.

It also has made him highly interested in the work of Bruce Kania, an entrepreneur and inventor near Shepherd who thinks he has a natural solution to the plague of disease-carrying midges and mosquitoes that spread EHD, bluetongue disease and West Nile virus, which have been killing pronghorns, mule deer, horses, cattle, pelicans and sage grouse.

In the broadest terms, Kania is proposing nothing less than “resurrecting the food web” in the pools, stock ponds and other bodies of water that are the incubators of disease-vector insects.

He would do so by introducing native minnows everywhere mosquitoes and midges incubate. Ideally, these same bodies of water would also host the manmade “floating islands” that he manufactures.

Kania is no pie-in-the-sky theorist. He has sold 5,400 floating islands worldwide since 2005. They range in size from a few square feet to a 50,000-square-foot island in New Zealand, but all are designed to do the same thing: to remove pollutants like nitrogen and phosphorous from water and use them to rebuild a healthy food chain.

Water thick with such nutrients produces little more than algae, crowding out most other life forms — except for mosquito and midge larvae. In healthy bodies of water, the nutrients feed biofilm, the slimy stuff that adheres to rocks and is the base of the food chain. Bugs feed on the biofilm; fish feed on the bugs.

“If we’re getting nutrients from our friendly neighborhood farmers,” Kania said, “why don’t we turn them into fish instead of algae?”

At Floating Island International northeast of Shepherd, where 19 water features dot 340 acres, the resurrected food web is readily apparent. Approaching one pond, Kania tells a visitor, “Walk along the edge here and just see what happens.”

What happens is that dozens of frogs go bounding from the grassy banks into the water. Elsewhere there are minnows and tadpoles, tiny snails, beetles, dragonflies, mayflies, crappies, sunfish, bluefish and perch, garter snakes, waterfowl, shorebirds and blue heron.

“This place is like a coral reef, in terms of its abundance,” Kania said.

Perhaps most remarkable is that a visitor, in the course of several hours on the property, did not see a single mosquito. They are present, but only as one of countless creatures, their numbers held in check by natural predators.

Kania’s patented “BioHaven” floating islands are made of recycled polymers from plastic bottles. Biofilms will attach themselves to the plastic alone, but when the islands are planted with native vegetation, the production of life is even more prolific.

Kania’s water features are fed by the Billings Bench Water Association’s irrigation canal, a water source loaded with nutrients from agricultural and residential runoff. But after flowing through his property, water goes back into the Yellowstone River with undetectable levels of nitrogen.

The phosphorous is trickier to measure, but in his 10th-of-an-acre minnow pond, Kania removed five pounds of phosphorous, which would have created 32,000 pounds of algae. And that same pond produced 72,000 healthy, native fathead and stickleback minnows in the past 10 months.

Unlike the gambusia, also known as the mosquito fish, which have been introduced in other states to eat mosquito larvae, Kania’s minnows are native to Montana and he says they are more efficient predators. Also, he said, his test pond produced similarly huge volumes of other mosquito and midge predators, including water beetles and dragon and damsel fly nymphs.

All those insects translate into a lot of fish. At Kania’s 6-acre fish-fry lake, he harvested 7,731 sunfish, crappies, perch and bluefish last year.

“It’s very likely the most productive wild fishery in Montana,” he said.

What Kania wants now is the opportunity to test his theories on a larger scale, perhaps on state or BLM land. Penfold, the former state BLM director, who lives in Billings and has known Kania for years, said he has been “encouraging agencies to take a hard look at this.”

“I don’t know what the other options are, and I’d like to see a real test,” he said.

Penfold said insect-borne diseases are having a huge economic impact in Montana, primarily hurting hunters and landowners because of reduced deer and pronghorn harvests in Eastern Montana. And if the federal government moves to protect sage grouse under the Endangered Species Act, there would be big impacts on agriculture and oil and gas development.

“I think it’s worth government money being invested in studying this,” Penfold said.

Kania plans to talk about his proposal when the Montana Fish, Wildlife and Parks Commission meets next Thursday in Helena.

Dan Vermillion, chairman of the commission, said he has a couple of Kania’s floating islands on his property near Big Timber, so he has already established his credibility. However, based on what little he knows about Kania’s plans for reducing insect-borne diseases, he has some serious concerns.

For one, even though the minnows are native to Montana, he worries about the introduction of a huge new biomass to state waterways. And given Montana’s “massive landscape” and countless ponds, stock ponds sloughs and stock tanks, Vermillion said, “it’s hard for me to understand how you could create enough minnows to have an impact.”

Kania said he understands the concern over introduced fish.

“Frankly, I’m on the same page as them,” he said. “I’m fighting invasives, too.

But given the scope of the problem with wildlife diseases, the minimal risk involved with native minnows seems worth it. “No response is not stewardship,” he said.

As for the size of the problem, Kania said, “our approach solves the issue of scalability.” Just from his property near Shepherd, he said, “I could engender and grow tens of millions of minnows — native, healthy minnows.”

One of the most problematic breeding grounds for mosquitoes and midges is the simple stock tank, which is usually 10 to 12 feet in diameter. Larvae are deposited in the tanks themselves and also in the muddy puddles created by water seeping out of the tanks.

Kania said he could introduce six minnows — three male, three female — to a stock tank, and when temperatures are above 50 degrees Fahrenheit, each female could lay between 250 and 325 eggs every five days. And a fathead minnow will eat up to 70 mosquito larvae a day. Newly hatched minnows are so small they would seep out of the tanks with the overflow and colonize the surrounding muddy ground as well.

But to avoid problems with fish introduction, Kania said he could also simply put small floating islands — some as small as three square feet — in stock tanks, ponds and even seasonal water features, without introducing minnows. These islands quickly engender all sorts of beneficial insects that prey on mosquito and midge larvae.

On his land, he said, “there’ll be times here when just clouds of damselflies are coming off the islands.”

Kania is exploring another possibility for a large-scale test of his ideas. On Sunday, he was planning to meet Bill Snell in Zortman. Snell is an enrolled member of the Crow Tribe who grew up on the Fort Belknap Reservation, where he owns property that houses what he says is one of the largest wetlands in the Milk River region.

“The mosquitoes up there are unreal,” Snell said, which is one reason he’s interested in allowing Kania to test his new methods there. But he also sees it as an opportunity to get Indian tribes involved in what could be a big economic and educational opportunity.

He sees the possibility of encouraging Indian youth to study biology, hydrology and other sciences that would be involved in the large-scale application of Kania’s ideas.

“I think one thing tribes like to see is demonstrations, not concepts,” Snell said.

That’s all Kania is seeking at this point, the chance to put his theories to the test. He doesn’t mind dealing with obstacles, he said. What bothers him is “the sense of hopelessness, that there isn’t an answer” to the problem of insect-borne diseases.

“We want folks to understand that there is hope,” he said.

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