A Fish For The Future Or Soon To Be One Of The Past?

In some obvious situations, the stocking of saugeye isn’t the responsible approach. Ohio doesn’t stock saugeye in the northern half (Lake Erie drainage) of the state, to avoid mixing them with native walleye. Oklahoma doesn’t stock saugeye in the east to avoid mixing them with native sauger stocks. But the answer becomes tougher in watersheds where both walleye and sauger coexist. Common sense indicates that where walleye and sauger have coexisted since the ice age, natural hybridization already has occurred between the two species.

Recent genetic research in Ohio, Tennessee, and South Dakota confirms this. The question remains, to what extent did they occur before man began collecting specimens, and are they increasing due to stocking? In most lakes where saugeye are currently stocked, the lakes are manmade or altered natural systems that don’t resemble the historic habitat present before man intruded. Many of these lakes eventually drain into large rivers with native stocks of walleye, sauger, and natural hybrids, also living in greatly altered environments.

This doesn’t mean it wouldn’t be prudent to try to protect the integrity of these native stocks. But the addition of a certain percent of manmade hybrids (from native species) into these systems probably would have a minor effect compared to damming, sedimentation, barge traffic, in-stream gravel mining, chemical pollution, and the introduction of non-native species.

Biologists are trying to reduce the addition of hybrids into main-stem rivers like the Ohio, by limiting stocking in nearby lakes and reducing or eliminating direct stocking into tributaries. Perhaps the addition of predators into these systems benefits other gamefish by helping reduce the numbers of juvenile forage fish. Fish such as gizzard shad and carp compete directly with gamefish at the juvenile stage, and they’re usually not the best forage species, due to their rapid growth past edible size. Research in Ohio has shown that in fertile reservoirs, gizzard shad numbers continue to increase, even with high numbers of gamefish present, and that juvenile shad directly compete with the young of largemouth bass and bluegill.

A Silver Bullet

Is there a silver bullet? Yes, thanks to genetic research. Research is being conducted by Dr. Konrad Dabrowski at Ohio State University in cooperation with the Ohio Division of Wildlife to determine the best methods to culture triploid saugeye. A triploid is incapable of producing offspring and would eliminate genetic mixing. The catch is, to make them a viable option, these triploids must be as hardy as normal saugeye and survive as well in hatcheries and in waters where they’re stocked.

Another solution may exist in lakes where the habitat and water quality is reasonably suited for walleyes. Through all the saugeye research conducted in Ohio—culture methods, stocking rates, timing of stocking, population estimates, growth and harvest rates, sex ratios, and now movement within watersheds—some lakes can conceivably switch back to walleyes with similar success rates. Ohio routinely raises 6 to 10 million saugeye fingerlings (not fry) per year and stocks 52 lakes. A lake’s stocking rate depends on water retention time in the lake among other things, with high-outflow lakes receiving higher stocking rates. The normal stocking range is between 100 and 300 fingerling per acre annually.

Two study lakes receive 500 fingerlings per acre to facilitate research. Interesting, though, these high rates didn’t reduce growth rates. Biologists ask, what if they were to stock walleyes at these new increased rates? Historically, lakes might have received only 25 to 50 walleye fingerlings per acre, a stocking rate some states have used for saugeye and considered their stocking unsuccessful.