LAKE VERMILION— The effects of a couple seasons of heavy fishing pressure may be starting to show on the walleye population here, even as a strong 2018 year-class promises to boost prospects for later in the season and years ahead.

Annual test netting on Lake Vermilion showed a noticeable drop in walleye numbers in the lake’s eastern basin, even as numbers on the west end held their own. Fisheries staff with the Department of Natural Resources conduct the test netting every fall and they typically report on their results in early April.

The latest results show that the DNR caught an average of 11.6 walleye per net, which is a significant drop from the 16 walleye per net recorded a year earlier. While last fall’s catch rate would be considered outstanding for most Minnesota lakes, it was the third-lowest catch rate in the past 25 years for Vermilion and is below the 25th percentile for the lake historically.

The drop in the lake-wide average catch was due entirely to a sharp decline on the lake’s east end, which saw its lowest numbers since 1994. Average walleye numbers are typically significantly higher on Vermilion’s east end than in the west, although the average size is smaller in the east. This year, however, the average catch was nearly identical across the lake. The average walleye catch in the east basin was 11.8 per net, while survey nets on the west end caught 11.3 fish on average, which is actually somewhat higher than the recent norm on that end of the lake.

“Fishing has been really good, but the human impact is there,” said DNR large lake specialist Matt Hennen, in response to the survey results.

In some respects, the lower walleye count could be a sign that the DNR’s recent narrowing of the protected slot has had the intended effect— allowing anglers to harvest more Lake Vermilion walleye. Previous surveys had shown that the slot limit had helped build up a sizable inventory of larger walleye and the recent decision to loosen the slot was designed to boost the harvest of those fish.

Hennen remains optimistic that the dip in walleye numbers is short-term, reflecting a couple different factors, including a weak 2017 year-class, which is reflected in lower numbers of walleyes on the small end of the “eater” range. Meanwhile, the average catch of walleye over 14 inches was still running above average on the lake, helped in large measure by very strong numbers of walleye over 14 inches on the west end.

“The numbers on west Vermilion are looking really good,” said Hennen. “There are lots of 14-20-inch fish over there.”

Not everyone is convinced that the walleye decline is as abrupt on the east end as the DNR netting suggests. Longtime guide Cliff Wagenbach notes that the winter bite was exceptional this year, which usually bodes well for the following year’s open water bite.

And even Hennen notes that the netting on Vermilion’s east end coincided with the arrival of a strong cold front, which often reduces fish activity for a day or two and could have reduced the total catch. Biologists note that such surveys are inherently subject to variability depending on a variety of factors.

While the 2017 year-class looks relatively weak, Hennen said the fall electrofishing results showed very strong numbers of young-of-the-year walleye, with the highest catch rate since 2007. The young walleye averaged 5.4 inches, which was near the long-term average for growth. Assuming that the 2018 year-class continues at least average growth, some of the larger fish are likely to be of harvest size by late this summer or fall. That’s particularly likely on the west end of the lake, where walleye growth rates tend to be higher.

If the number of eater-sized walleye is slight reduced this year, anglers are likely to turn to jumbo perch as a replacement. “The numbers of jumbo perch have just exploded,” said Vermilion fishing guide Rob Bryers. “This past fall, it was not uncommon to bring in four-to-six jumbo perch a day, many in the 12-13-inch range.”

The DNR test netting bears that out, with an average catch rate of 24.9 perch per net, the highest catch rate since 2014. The above-average catch rate of perch over nine inches “will likely provide harvest opportunity,” according to the DNR survey report.

Meanwhile, smallmouth bass are becoming a steadily-increasing part of the Lake Vermilion fishery. Fall electrofishing tallied a total of 75 fish an hour, the highest ever observed on Lake Vermilion. The high lake-wide average was driven largely by the extraordinary numbers of smallies found on the west end, where the DNR tallied a total of 145 fish per hour. That compares to the historic average over 48.5 bass per hour. The harvest on the east end, at 40 fish per hour, was slightly above the long-term average.