Fishermen, biologists worry about fish kills at Lake Taneycomo

Winter can’t get here fast enough for the trout, say fishermen and hatchery managers at Lake Taneycomo.

The prolonged mild weather this fall has produced a nightmare that has lasted almost a month, producing large fish kills in the hatchery and sluggish fish in the lake.

The problem stems from a string of natural events that combined to form one big problem. At Table Rock Lake, which feeds Lake Taneycomo, water has remained warm and low in dissolved oxygen. Add the abundance of debris in the water from a summer of flooding — debris that is now decaying and robbing the water of even more oxygen — the situation becomes even more threatening.

When that water comes through the dam and enters Lake Taneycomo, it carries problems. Water quality is poor, with high nitrogen and sulfur levels and low dissolved-oxygen readings.

With no major releases to provide increased flows, those factors have killed some trout at Taneycomo, though officials would offer no estimate of how many.

There is only one cure to the situation now going on, fisheries biologists say: cold weather.

“We’re waiting for it to get cold, causing Table Rock to turn over and get a mixing of water,” said Shane Bush of the Missouri Department of Conservation. “When the water temperature at the surface matches the temperature at the bottom, that produces better water quality.

“That’s about the only way this situation is going to get better.”

In the meantime, workers at the Shepherd of the Hill Hatchery, a Department of Conservation facility on the banks of Lake Taneycomo, are on high alert. They’ve been working hard to save struggling trout, transferring them to raceways at the hatchery with better water quality or to other cold-water hatcheries such as Bennett Spring, Montauk and Lost Valley.

And fishermen continue to struggle to catch fish.

“The fishing is about as slow as we’ve ever seen it for this long,” said Phil Lilley, longtime owner of a marina and resort on the lake. “But I can give you cases where people are catching some rainbows off our dock chuck full of scuds. Most of the fish I have been catching are fat and still fight pretty hard for being so stressed. So it is confusing ... why they’re not biting on at least our flies.”

Problems with low dissolved oxygen are nothing new at Lake Taneycomo, one of the nation’s best trout fisheries. They crop up every fall, when flows are reduced and oxygen levels drop. But this year stands out.

Part of that can be attributed to all of the debris in the lake from the summer floods. That decaying debris, the algae die-offs and hot temperatures have depleted water quality. Fishermen have seen the effects, both in the slower fishing and the fish kills.

The die-offs have affected trout of all sizes, from small rainbows to big browns. But in the overall scheme of things, the fish kills aren’t a catastrophe.

Downstream from the shallow upper end, there are still plenty of healthy trout, the scud population has boomed and the hatchery is maintaining its stocking schedule, just putting fish in where there is better water quality.

“We think the colder weather will help greatly with our water quality,” Bush said. “We’re just waiting for it to come.”

This story was originally published November 18, 2015 at 10:13 AM with the headline "Fishermen, biologists worry about fish kills at Lake Taneycomo."