Jack Mull decided to try his hand a few years ago at keeping a tank of tropical fish at the same time he began messing with a greenhouse.
Late last month, he walked into that greenhouse and tossed a handful of fish food into that 6,000-gallon tank and the water boiled as 5- to 15-inch tilapia splashed and fed on the surface.
APRIL 1, 2016
Highlights
Jack Mull raises tilapia to feed to Kansas fish
African fish have hundreds of fry per week
Cold winters keep tilapia from overpopulating
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| Jack Mull looks at a tilapia he’s using to produce fry to feed gamefish. He said one tilapia produces 200 to 300 fry every few days. Michael Pearce The Wichita Eagle |
RICE COUNTY
Jack Mull decided to try his hand a few years ago at keeping a tank of tropical fish at the same time he began messing with a greenhouse.
Late last month, he walked into that greenhouse and tossed a handful of fish food into that 6,000-gallon tank and the water boiled as 5- to 15-inch tilapia splashed and fed on the surface.
Mull smiled at the prospects of how much food he saw before him, but he plans on feeding the tilapia to other fish on his property, not to people.
“Tilapia that are 3 to 5 inches produce 200-300 fry about every two or three days,” said Mull, explaining that he had about 150 brood tilapia in the tank. “That’s a lot of protein I can feed my other fish. You can’t have too many baitfish if you’re wanting to grow a lot of big fish in your ponds.”
When he retired from his career as a doctor in 1999, Mull decided he wanted “to make the best fishing ponds in the state of Kansas” on property he owns north of Hutchinson.
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| Jack Mull throws food to a tank of 150 tilapia, which reproduce the fry he uses to feed gamefish. Michael Pearce The Wichita Eagle |
Mull is a voracious reader and self-professed experimenter who “just likes to try things to see what works and what doesn’t.” He learned he needed quality water, good habitat and, of course, plenty of food.
His 400-plus acre property sits amid the sandhills, where good, healthy water is not far below the surface. Rainwater coming in from surrounding pastures is also fertile and clean. Through the years, he’s tried adding a wide variety of structures to his five ponds that total about 45 acres. His days of adding trees, and watching them eventually rot or just fall apart are over.
“So far this year I’ve added 28 loads of concrete and blocks, and it’s 20 tons per load,” Mull said, about the time a huge trackhoe had placed the last of a load of mixed concrete waste chunks at one of his ponds.
Little minnows for big gamefish
Mull knew that if wanted to grow lots of big fish, he’d need to provide more food than most standard pond fisheries can produce on their own.
Like some pond owners, he’s added lots of fathead minnows to his ponds. It’s especially beneficial if the minnows are added to an unstocked pond, and given some time to reproduce, before gamefish are added. He adds about 40 pounds of fathead minnows, at about 400 minnows per pound, per week during the spring and summer to established ponds.
Mull said he resisted the advice of stocking gizzard shad, a common forage fish in Kansas’ larger lakes and reservoirs, into his ponds, which range from about one-half to 20 acres.. His research showed any shad that don’t get eaten eventually turn into fish large enough to compete with game fish for food and space.
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| Jack Mull looks at a tilapia he's using to produce fry to feed gamefish. He said one tilapia produces 200-300 fry every few days. Michael Pearce The Wichita Eagle |
He learned of tilapia on a trip to Florida, where the species’ proliferation can cause over-population problems. Mull figured that wouldn’t be a problem in Kansas.
“Tilapia are a warm-water fish. Once the water starts to get cool in the fall, they die off,” he said. “They produce great forage, but they can’t be a threat to other kinds of fish. It seems about perfect.”
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| Jack Mull throws food to a tank of 150 tilapia, which reproduce the fry he uses to feed gamefish. Michael Pearce The Wichita Eagle |
Mull said 60 degrees is the point where tilapia start to die, and their peak spawning temperature is around 80 degrees.
Walking inside from a cool mid-March morning, the greenhouse’s 92-degree internal temperature and humidity was enough to instantly steam glasses and camera lenses. At 70 degrees, it won’t belong before the brood fish begin to spawn. He’ll stock many thousands of tilapia in his ponds to feed gamefish in the spring and summer when the water stays above around 60 degrees. When he’s done feeding for the year, the water in the tank will drop to somewhere between spawning and survival levels. That will keep the brood fish alive, but they will stop spawning.
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| Jack Mull checks the filter system, which uses snails, on his 6,000 gallon tank where he raises tilapia to feed to gamefish in his ponds. Michael Pearce The Wichita Eagle |
As well as unconventional baitfish, Mull has unconventional game fish in his waters. He is one of few landowners who annually stock trout a in a private pond in the fall. He said the warming water temperature will probably kill the fish soon, if not already.
He’s been able to get species of fish not normally associated with Kansas ponds to flourish. Records show the largest wiper to come from one of his ponds was more than 8 pounds, though the average is half of that. He’s produced walleye, possibly the accomplish he’s most proud of, to around 26 inches within three years of initial stocking. Many of the fish in his ponds have been tagged so they can be identified, measured and weighed so growth rates can be monitored and feeding rates adjusted. He’s constantly looking for something new to try.
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| One of small pit-like ponds where Jack Mull raises fathead minnows to feed his gamefish. Michael Pearce The Wichita Eagle |
After checking the tilapia tank he pulled his pickup to a pond of about a half-acre, and urged a guest to make a few casts with small spinning gear.
On the first cast a golden-colored, 7-inch smallmouth bass hit the lure. It was so plump that it looked like it had swallowed a ping-pong ball. A few casts later, a smallmouth just as stocky and more than 10 inches was unhooked and released.
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| Last fall smallmouth pass three to five inches were stocked in a pond of Jack Mull's. Some are now more than 10 inches long. Michael Pearce The Wichita Eagle |
“When we stocked them last fall, they were 3-5 inches,” said Mull. “There’s no doubt they’re eating well and growing.”
The pond also holds yellow perch and red-eared sunfish stocked last fall. Mull is particularly interested in seeing the size of the yellow perch, a fish primarily of the northern U.S. and Canada. He’s asked a friend to come to the property and specifically target such fish.
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| Jack Mull checks the solar-powered pump he uses to keep quality water in a pond where he raises smallmouth bass, yellow perch and red-eared sunfish. Michael Pearce The Wichita Eagle |
For the love of tinkering
Driving the soft roads that weave around the sand dunes on his land, Mull pointed out several other projects. Food plots are well located and scattered to feed upland birds, deer and turkeys.
Eventually he stopped at one of his larger ponds, where friends Dudley and Karen Burgess were casting spinning gear, catching enough bass and bluegill to help stock a neighbor’s pond. They had three walleye, some slab crappie and a small wiper in a basket. The two best walleye were about 17 inches. All were dark-colored with bulging bellies.
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| With plenty of food and habitat, Jack Mull is able to raise walleye with good growth rates in ponds in Rice County.Michael Pearce The Wichita Eagle |
Mull said the fish were probably about 2 years old. The walleye were released so they could keep growing.
Even though the fish were biting, he got in his truck and left, saying he rarely had time to fish. He’s still active in several business ventures and has developed a passion for trying to find ways for central Kansans with Lyme disease to find better care.
“Oh, I really love tinkering with stuff,” he said, when asked why he doesn’t fish more. “In fact, I really thrive on it.”
This post is on Healthwise
