Mississippi anglers love crappie. They love them so much, they want them everywhere — including the smaller state lakes and small private ponds.
That’s a problem.
Crappie quickly over-populate in smaller waters, resulting in a population of fish too small to interest anglers and too large to be bass forage.
An obvious solution is a non-reproducing crappie.
Enter the Magnolia crappie.
The Magnolia crappie is a cross between a male blackstripe crappie, a color variant of the black crappie that occurs naturally in low numbers in some Mississippi impoundments, and a female white crappie.
The blackstripe crappie — also called a blacknose crappie — is recognized by a narrow, dark stripe from the dorsal fin forward down the top of the head and continuing on the underside of the head to the back of the mouth.
The hybrid offspring of the male blackstripe crappie and the female white crappie retains the black stripe. Using the blackstripe crappie as the male parent instead of a normally colored black crappie allows hybrids produced in the hatchery to be easily recognized.
But hybrid crappie can reproduce, so just making hybrids doesn’t accomplish the goal of controlled reproduction needed to effectively manage crappie in small impoundments.
Hatchery scientists have one more trick — they make the crappies triploid (pronounced trip-loyd).
Crappie, as most fish do, have two sets of chromosomes. This is the diploid (pronounced dip-loyd) condition, and diploid fish reproduce normally.
Triploid crappie have three sets of chromosomes. Cellular processes necessary to produce viable eggs and sperm break down when there are three sets of chromosomes.
It is the triploid condition that prevents the triploid hybrid crappie from producing offspring. The fish produce eggs and sperm and mate, but the fertilized eggs do not develop.
Triploid offspring are produced by stripping eggs from normal female white crappie and fertilizing them with sperm stripped from normal male blackstripe crappie. Several minutes after fertilization, the eggs are put into a pressure chamber and exposed to high pressure for a brief period time.
This interrupts the normal cellular processes and results in the egg retaining an extra set of chromosomes.
The fertilized egg and the offspring that develops from it have three sets of chromosomes and cannot produce offspring.
But crappie reproduction is controlled only if all the stocked fish are triploid. Unfortunately, the procedure is not yet foolproof.
The percentage of offspring that are triploid has ranged from 60 percent to 100 percent, so work remains to refine the process.
Fish can be tested to see if they are triploid by analyzing a tiny blood sample from each fish. The process does not injure the fish but is very labor intensive and limits the number of fish that can be stocked.
The ‘reel’ test
Producing fish is one thing. Producing quality crappie fisheries and satisfied anglers is the ultimate goal.
The Magnolia crappie program has only been in place for several years, so MDWFP biologists await answers to key questions like post-stocking survival, growth rate, angler catch rate and whether the engineered fish are spawning.
There is some evidence that Magnolia crappie do better in some lakes than others. Mississippi State’s Dr. Wes Neal and his students are looking at factors affecting the success of Magnolia crappie stocking.
Last fall, almost 24,000 4- to 5-inch-long Magnolia crappie were stocked into Lake Bill Waller; Lake Columbia; Tippah County Lake; Charlie Capps Wildlife Management Area Lake; and lower, middle, and upper Olive Branch Lake.
This year was a tough year for producing Magnolia crappie, and only 9,800 were stocked into grow-out ponds at the hatchery. It’s been a hot summer, and hatchery manager Charles Silkwood and the staff at North Mississippi Fish Hatchery have worked hard keeping this year’s crop of Magnolias alive and growing.
The number of Magnolia crappie available for stocking will not be known until cooler weather allows the hatchery staff to harvest the ponds.
Priority for this year’s fish will be the lakes that State’s Neal will be studying: Tippah County Lake, Lake Walthall, Lake Monroe, Simpson County Lake, Lake Claude Bennett and Lake Tom Bailey.