The famous Kinkaid Lake record crappie, caught almost a year ago and proclaimed to be a new Illinois state record black crappie, was the center of attention of anglers nationwide even before its most interesting feature was made public. The 4 lb. 8.8 oz. fish was identified and measured by Illinois Department of Natural Resources officials, who then sent a fin clip off to verify their conclusion via genetic analysis. The results determined the trophy not to be a true black crappie, but a mix of black and white.
The Kinkaid crappie is not an uncommon specimen. According to a 2008 survey, almost all lakes in southern Minnesota with both species – black crappie and white crappie – have hybrids, too, albeit at low frequencies. About 3% of crappie in these lakes were hybrids, but other states report hybrid proportions of up to 50%.
Many factors contribute to the likelihood of black and white crappie hybridization. Most important is the genetic similarity of the two species, which allows fertilization and proper development to happen at all. When the overlap of spawning habitat and spawning season are considered, it is not surprising that the two crossbreed.
Hybrids almost always look identical to black crappie, though experts don’t rely on the infamous bars to determine which species they’re holding. For an accurate identification, they count the dorsal spines; black crappie and hybrids have seven or eight, while white crappie have five or six. (Hint: it’s easy to remember if you keep in mind that “white”, “five”, and “six” all have i’s.) To discern a black crappie from a hybrid, however, you’ll need to analyze its DNA. Fisheries biologists recognize that historic record black crappie may have in fact been hybrids, but there is no way to verify them now.
While they may look identical to black crappie, hybrids demonstrate an impressive growth rate that eclipses that of either black or white crappie. In a survey which examined black crappie body lengths, 82% of the statistical outliers – or the very largest of the fish that were examined – were later defined as hybrids. These fast-growing fish theoretically have the ability to outcompete their parents, so why haven’t they effectively eliminated black and white crappie?
The first generation of a black x white cross are fertile and can mate with other hybrids – or even backcross with a parent species. However, the hybrids’ offspring display significantly reduced survivability and reproductive ability. In fact, a 2006 study in Alabama reported that first generation hybrids are more than six times more prevalent than all subsequent generations combined.
Because of this combination of faster growth and stunted reproduction, aquaculturists have learned to stock hybrid crappies rather than either parent species. Both black and white crappie are known to quickly overcrowd a body of water, which leads to a population of stunted fish. Stocked hybrids are usually the offspring of female black crappies and male white crappies – the same recipe that resulted in the Kinkaid Lake record crappie.
Unfortunately for anglers, studies suggest that these larger hybrids are harder to catch than their parent species. Biologists have noted that hybrid catchability is lower than their abundance would suggest, but hybrids are found in a wider habitat range. While white crappie tolerate silted, turbid conditions much better than their vegetation-loving black counterparts, hybrids can be found in any area where either parent species could be.
Biologists are already analyzing the DNA of the new state and world record crappie caught on May 15, 2018 in Loudon County, Tennessee. Lionel “Jam” Ferguson’s 5 lbs. 7.68 oz. brute was initially visually identified as a black crappie by a Tennessee Wildlife Resources Agency official, but the genetic results that verify or reject this identification will be back within weeks.
Originally posted in Outdoor News Minnesota.