When anglers land a prize walleye, northern, lake trout or muskie, they usually don't think about the modest tullibee, an important prey species found farther down the chain.
Yet as the tullibee goes, so goes our beloved game fish.
"Tullibees are a great 'canary in the mineshaft' species," said Peter Jacobson, a DNR habitat research group supervisor. "If you have tullibee in a lake, you know things are pretty good. If they are declining, you know something is wrong."
Yet there is a significant decline in tullibee numbers, Jacobson said. There are no hard numbers, but annual test netting indicates fewer fish, he said.
Tullibees, also known as cisco, thrive in cold, oxygen-rich water. These small, silver-sided members of the salmon family typically weigh less than one pound, but can reach weights of several pounds in inland lakes. Even slight changes in temperature and oxygen levels can cause die-offs of this sensitive fish.
Besides being a valuable forage fish, tullibee have a small-but-loyal following among ice anglers. Tullibees are usually targeted in late winter, when anglers can catch the small whitefish in deep water with small baits, including wax worms. But for Minnesota's prize game fish — especially walleye, muskies and lake trout — tullibees are a favorite meal year-round.
That meal, though, is not found everywhere. According to the DNR, "Minnesota contains more high quality cisco lakes — those rich in tullibee — than any other state in the Lower 48; 600 lakes contrasted to only 200 in Wisconsin."
In Minnesota, the tullibee is primarily found in the cold, deep lakes of the north. More than 40 percent of tullibee lakes are in the prime recreation destination of north-central Minnesota. Yet this same region, with its alluring lakes and forests, is seeing rapid commercial and private development. And when shoreline or woodland parcels are developed, erosion and runoff start muddying the waters for the tullibee. Fertilizers, reduced shoreline vegetation and the loss of tree cover add to the tullibees' problems.
Additionally, a problem is their delicate nature. Michael Duval, a district manager in the DNR's Division of Ecological and Water Resources in Brainerd, said tullibees require cold, oxygenated water to survive. "That's a problem for this species in late summer because the water near the surface becomes too warm and the water at the bottom contains too little oxygen," Duval said. "As a result, tullibee become trapped in a narrow band of habitat somewhere in between, sometimes only a few feet in depth. If the water warms too much from the top down or oxygen depletion extends too high from the bottom up, the fish die."
Jacobson said tullibees are especially vulnerable to climate change and eutrophication (or excessive nutrients that stimulate oxygen-depleting aquatic plant life). "Healthy forests and undeveloped or minimally developed shoreline can help prevent tullibee die-offs by keeping nutrients on the land, slowing their oxygen-depleting impacts."
Landowners can help
The situation with the tullibee illustrates the complex ecological relationship between forests, lakes, fish species and fishing quality.
But if the problem is complex, so is the solution. Preserving tullibee habitat will require the participation of private forest landowners, government units, and a menu of public and private agencies.
Owing to a $400,000 appropriation from Minnesota's Clean Water Fund, a consortium of Minnesota agencies launched the Tullibee Lake Watershed Forest Stewardship Project in the summer of 2013. The project got started by targeting tullibee-rich waters in seven north-central counties: Aitkin, Becker, Cass, Carlton, Crow Wing, Hubbard and Otter Tail.
This initiative is primarily a vehicle for encouraging private landowners to help with conserving tullibee habitat. Landowners are provided with a forest stewardship plan, which in turn qualifies them for property tax relief and financial assistance for projects that help keep water clean.
Gary Michael, the DNR's coordinator for the Private Forest Management Program, emphasized that partnerships are key to this initiative.
"Linking forestry and water quality seems like an easy, obvious link, but it isn't," he said. "As public agencies working with natural resources, we must recognize the need to work with private landowners if we want to reach our goals."
So far, the project's main takeaway is the importance of conservation-minded private forest landowners. While the tullibee forms a pivotal link in the fishery food chain, private forest landowners form an essential link in the conservation chain.
"The roots of good fishing stretch deep into Minnesota's forests," Duval said.
Peter Bundy, a certified forester, has been a consultant with private forest landowners on the tullibee project for the past two years. "Since forests surrounding targeted tullibee lakes are critical to maintaining water quality, it makes sense (and cents) to help protect them," he wrote in an e-mail.
In other words, what's good for the tullibee is good for the game fish and the 1.4 million people who fish Minnesota's lakes every year.
Jim Umhoefer is an outdoor writer and photographer from Sauk Centre, Minn. Find him online at www.candidperceptions.com.