In a different line of investigation, James Schneider of the Michigan DNR reported results of an experiment designed to improve stunted bluegill lakes by stocking large walleye fingerlings, in conjunction with catch-and-release regulations, and reduction of bluegill numbers with the toxicant antimycin. He found that stocking large fingerling walleyes helped reduce the density of small bluegills, thereby allowing the production of more acceptable-size fish. Catch-and-release regulations, in conjunction with bluegill reductions, also worked well.

Regulations

Of course, once walleyes have reached catchable size, anglers rush to harvest them. Walleye length-limit regulations have been studied for years, with variable results and little similarity among bodies of water or regions. The rise in walleye popularity in Alberta led to drastic declines in fish populations in these northern fisheries, characterized by slow growth and low productivity.

Strict harvest regulations, such as 20-inch minimum-length limits, were enacted in the 1990s to preserve populations, but biologists feared that illegal harvest could render the regulations useless. A study from 1991 to 1999 found that indeed anglers either were ignorant of regulations or chose to ignore them, as legally protected walleyes comprised 19 percent of the harvest. Biologist Michael Sullivan also found that more walleyes were illegally kept when anglers didn’t catch many.

Illegal harvest apparently wasn’t a problem at Lake Francis Case, where a seasonal length limit of 14 inches (April through June) was enacted in 1990, along with a reduction in daily bag and possession limit from 6 and 12 to 4 and 8 walleyes. Cliff Stone of the South Dakota Game, Fish and Parks called the regulation a success, which was enhanced by excellent walleye recruitment through the 1990s, following high inflows in the Missouri River.

Last year, the regulation was tweaked with a 15-inch minimum and a restriction to just one walleye over 18 inches in order to maintain the excellent walleye fishing. Also, the duration of the length limit was extended from 3 to 10 months (September through June).

In the most southerly walleye fishery in the United States, Texas researchers reported that a 16-inch minimum-length limit at Meredith Reservoir was successful in increasing walleye abundance, though it has been altered to allow anglers to harvest two walleyes under 16 inches per day. The change was enacted to prevent stockpiling of fish just below the legal size, since growth is fast in Texas, but fish don’t grow as large as in more northern regions, because they don’t live as long.

Saugeye Studies

Kay Hill of the Iowa DNR reported on comparisons of stocking walleyes and saugeye into two Iowa lakes. In this case, fish were freeze-branded for identification. One notable finding was that young saugeye are more vulnerable to night electrofishing than walleyes, potentially biasing electrofishing evaluations of stocking success.

Walleyes and hybrids stocked in June at two inches showed generally equivalent survival into fall. Saugeyes grew faster than walleyes during their first summer, while growth rates of older saugeyes and walleyes were similar. Total mortality of the two groups was similar in one lake but slightly higher for saugeyes in the other lake.

Anglers also harvested saugeyes at a slightly higher rate. Hill recommended that future stocking be with walleyes rather than saugeye, based on production costs that averaged 70 percent greater for saugeye. At angler harvest, saugeyes were 50 percent more expensive to stock than walleyes.

These oral presentations at the Midwest Fish and Wildlife Conference will be the basis of a series of papers to be published in the North American Journal of Fisheries Management, a key scientific outlet for the American Fisheries Society. Anglers can expect ever better management of walleye populations and a better understanding of the biology of the species.