Inside cool water-filled tanks in southern Ohio, the laws of nature are being defied. Female yellow perch mate with other female yellow perch; male bluegills with other male bluegills.
This might make one wonder, unless, of course, your profession is selective breeding of fish, and your goal is to get them to grow faster. Hanping Wang, who manages The Ohio State University’s Ohio Center for Aquaculture Research and Development, has succeeded in raising faster-growing fish by artificially mating them in a not so typical way.
On average, the resulting offspring reach market size six months faster than bluegills or yellow perch bred out of standard male-female mating. That’s because among yellow perch, females grow quicker than males. Among bluegills, males grow faster than females.
For an Ohio fish farmer, having fish that mature faster than average could be a significant savings in fish food and in time waiting to sell them, said Wang, whose center in Piketon is part of Ohio State’s College of Food, Agricultural, and Environmental Sciences (CFAES). The aim of the center is to spur the state’s aquaculture industry, in part through research on two of the state’s most common fish: yellow perch and bluegill.
Aquaculture, the practice of raising fish in a controlled environment of indoor tanks or outdoor ponds, is slowly growing, but still a relatively small Ohio industry. In 2017, 227 people in the state had permits allowing them to sell seafood. Any advances in farming that make it faster or easier to raise fish or shellfish could prove useful and profitable.
“We’re using the animals’ maximum potential to make them grow faster for human benefit,” Wang said. “We have to do it this way to meet the growing need for food, specifically protein. You need to have a process to produce more animals — more chickens, cows, pigs and fish.”
Among yellow perch, the females grow 60 to 70% faster than the males, and they grow larger than the males. As a result, it makes sense that a breeder would want to produce the fastest-growing female yellow perch. So Wang did exactly that. He mated females to females with the help of grants from the U.S. Department of Agriculture and the state-based Ohio Sea Grant program, which funds research in the Great Lakes and aquaculture.
On average, it takes a farmer 16 months to raise a yellow perch to reach market size. Now it can take as little as 10 months if neo-males are mated with typical female yellow perch, Wang said.
“The farmer saves on labor, saves on feed and saves on space,” he said.
With bluegills, the males grow faster and bigger than the females. So, Wang took males and mated them with males through a process similar to what was done with the yellow perch, so they became what Wang calls “neo-females.” The offspring of a neo-female bluegill and a male bluegill were all male fish that could grow to 1 pound, the size needed to sell them, in about a year, cutting three to five months off the typical time needed for them to mature.
“It doesn’t matter if it’s a fish or a tomato or a soybean, if you can shorten the amount of time it takes to grow the item to market size while still maintaining the same nutritional quality, that will just improve the farmer’s profit margin,” said Matthew Smith, an OSU Extension aquaculture specialist. Smith’s main priority is expanding sustainable, profitable fish farms in Ohio.
Aquaculture can play a critical role as our oceans and Great Lakes are overfished, Smith said. “It’s a way to provide a balance.”