PIKETON, Ohio — The aquacultural world of pond-raised fish is governed mainly by two market demands: fish size and filet quality. An absence of either one could leave individuals in the business floundering.
Ohio State University Ohio Agricultural Research and Development Center aquaculturists Han-Ping Wang and Geoff Wallat are leading a team of researchers in a U.S. Department of Agriculture-funded project to make sure that Ohio's most popular fish — yellow perch — meets those requirements.
"Markets want fish that are 8-11 inches long and produce a 4-5 ounce filet. And it's expected that 90 percent of the fish reach that size within 18 months," said Wallat with OSU South Centers at Piketon. "In Ohio, usually only 50 percent of pond-raised perch reaches that market size and it takes them 18 months to do it. The purpose of our study is to improve the consistency of size and reduce the time it takes to reach that size."
In order to do that, researchers are crossbreeding strains of yellow perch found throughout the country in the hopes that genetics will create the perfect fish. Strains of yellow perch from Maine, New York, Pennsylvania, Wisconsin, Nebraska, North Carolina and Ohio are being studied through a number of crossbreeding variations to determine which, if any, would make a faster growing, larger growing yellow perch.
"It's not uncommon for pond-raised perch to have variable growth rates. But because of those variable growth rates, it takes longer for some of the fish to reach market size and the population that does reach market size is not high enough for market standards," said Wallat. "There are also some problems with semi-wild brood stock being used with pond-raised fish, which also may inhibit optimum market size. Not a lot of work has been done with genetics and we are hoping that genetics will produce a more uniform fish."
In a recent study conducted at Purdue University, data has shown that at water temperatures of 72 to 74 degrees Fahrenheit, North Carolina strains of yellow perch grew quicker than several other geographical strains being studied. Preliminary data from the Ohio State study has shown that the Ohio strain has outperformed geographically related strains such as Pennsylvania and New York.
In one aspect of the project, researchers are crossbreeding the North Carolina strain with the Ohio strain, banking that genetics and geography will produce a high-performance fish.
"Sometimes geographically related species, such as Ohio and Pennsylvania, are close genetically, which may not be what we always want. It may be that the least-related is what performs the best," said Wallat. Ohio strains have so far outperformed Pennsylvania and New York strains of yellow perch.
"We also have to be careful with what we take with us when we select for certain traits. We don't want to produce a fish that is susceptible to disease or produces poor muscle quality," said Wallat.
Researchers are in their second year of the four-year work, selecting the top 10 percent group for growth per generation and using that group as the basis for the next breeding generation.