Fish breaking many of your rules

Sooner or later the fish will violate most of your “hard and fast” rules for catching them, but the tendencies supporting those rules still are worth paying attention to.

Rule 1 is fish where the fish live. No matter how skilled you are at choosing and presenting lures, you can’t catch them if they’re not there.

In stream fishing for smallmouth bass, based on my experience and the wisdom of the late Tim Holschlag, author of several esteemed books on river and stream smallmouth fishing, the high-percentage spots will have a rock-strewn stream bed.

Rocks serve as “food larders, hiding places and ambush cover,” Holschlag wrote in his 1990 classic, “Stream Smallmouth Fishing.” Rocky substrates, he wrote, are especially attractive to smallmouth, whose preferred summer food source, the crayfish, thrives in the crannies between submerged rocks.

The likeliest spots also will feature depth sufficient to hide the bass from the eyes of overhead predators (including you), water clear enough for the sight-feeding bass to see your lure and current swift enough to consistently convey prey but not so swift that it strains the fish’s ability to hold comfortably in ambush sites.

The rock substrate is of course a constant, but the stream’s depth, clarity and rate of flow fluctuate with the volume of water in the stream. Fish the rock, and the fish will tell you if the depth, current and clarity meet their standards.

Until recently I have believed in a corollary of the depth rule — that shade is another important characteristic of the optimum river smallmouth spot — but after the last two Sundays I am less sure.

Two weeks ago, on a sunny, blue-sky Sunday, Mike Jacobs of Monticello and I floated a few miles of the Wapsipinicon. In seven hours we caught 40 bass, four walleyes and two northerns, which we considered a fun outing. But we caught most of them in the first few hours, when shoreline trees and bluffs shaded the water along the banks.

With the overhead sun spotlighting most of the likely spots, elevating the native caution of any fish there, the second half of our outing was noticeably less productive. We expected that and took it as additional confirmation that a summertime river smallmouth angler would be well advised to concentrate on low-light conditions — morning, evening and overcast days.

A week later, on another sunny, blue-sky Sunday, Mike, Ray Thys of Marion and I anticipated similar conditions — and results — on a Maquoketa River float trip that checked all the boxes: rock, current, clarity and depth.

Throughout the morning, we caught fish after fish along the shaded banks — action I expected to subside when the sun, at its zenith, erased the shadows. But the fishes’ increased exposure did not inhibit their activity.

Though they may have moved slightly, into riffles and other faster-current areas where disturbed surface water provided overhead cover, we continued to catch them at the same exhilarating pace we had enjoyed in the morning.

At trip’s end, seven hours after its start, the three of us had combined for 100 smallmouth, five each of largemouth and walleye and a smattering of rock bass, bluegills and sunfish.

Though the trip put a big dent in my shade theory, it confirmed the one hard and fast rule of fishing: Go whenever you can.