Baitfish: inches not millemeters of trout food

Working up the cooler trout stream, the next section electroshocked yielded 51 yellow perch and 23 sculpins, with one or two examples each of white suckers, creek chubs, horny headed chubs, mud minnows, fathead minnows and black bullheads. This came to 800 baitfish per mile. Encouraging was the presence of 10 small (less than 4 inches) trout--these would be the young-of-the-year trout. A stretch of the same stream farther up yielded large numbers of sculpins (63), creek chubs (65) and red belly dace (58), with lower numbers of white suckers, hornyhead chubs and a couple examples of shiners, minnows, and black bullheads. Eleven small trout were also present.

The eye opener was a small (6 inches to 10 inches wide), spring-fed stream. Here the young-of-the-year trout (under 4 inches) numbered 78, or more than the numbers of sculpins (23), creek chubs (11), red belly dace (8), mud minnows (5), white suckers (3), and brassy minnows (2) combined. It is interesting to note the low baitfish diversity (six species) in this cold, spring-fed stream, with excellent trout reproduction, compared to that of the larger, warmer stream with 13 species. Also interesting is the close correlation with increasing trout numbers and sculpins numbers. Simply put, the more sculpins present, the more trout collected.

Given their abundance, any of these common baitfish is worthy of imitation, particularly the sculpins, chubs and, yes, even young trout (adult trout aren't averse to eating their offspring). Maybe you could even come up with an 8-inch lamprey imitation for those warmer
stretches of stream!

By Dean Hansen

A snowflake. In August. With three tails.

I stared in amazement at the contents of the collecting net I had been sweeping over the Apple River in Wisconsin one August evening. There was the usual load of midges, a few caddisflies; and the tiniest, most delicate, whitest, indeed the most Lilliputian mayfly I had ever
seen in my life.

All mayflies, even the inch-and-quarter-long Hexagenia, are delicate. This speck of dander, however, measuring just 3/32nds of an inch end to end, gave new meaning to the words "delicate" and "minute." The pleasures of tying and fishing an imitation of this mayfly would approach those of the medieval practice of self-flagellation; and fly fishing and fly tying are supposed to be fun, right? I quickly snapped a couple photographs of this tiny member of the mayfly genus Caenis, and I began to long for something big to write about.

Yah, something big. Something you can drop in the streamside weeds and find again--in the dark. A fly pattern you can pin on your vest and another angler can identify from 50 feet away. Something you can measure in inches--not millimeters. Something really big, like a #4 or even a #2 hook size. Something like baitfish.

Baitfish. Anyone who has used a kick net to collect insects in a stream also has inadvertently captured examples of the smaller fish that share the stream with the much larger trout. Sticklebacks, shiners, perch, chubs, mud minnows--the variety and number of small--fish in the one-to-two-to-three-inch range in streams is impressive. And they're all fair game for hungry trout. In fact, studies of the gut contents of larger (over 10 inches) trout again and again show that a baitfish's life in a stream can be pretty dangerous and can end in a gulp.

I participated in an electroshocking survey on three different streams two years ago. Seeing the numbers and variety of small fish in a stream was educational. Watching that electrified wand pull trout after trout from their hiding places was exciting enough. But to be
along with a real expert on both trout and baitfish, Conrad Schmidt, was both a pleasure and privilege.

The first stream we sampled, while it did hold large trout, didn't support trout reproduction. It had warm-water input from a couple of lakes, a low gradient and a sandy or muddy bottom. In its warmer stretch, there were 13 species of baitfish. There were only two to four examples
each of sculpins, common shiners, mud minnows, fathead minnows, black nose dace, black bullheads and tadpole madtoms (there's a name!) collected. The two most common species were creek chubs (44) and hornyhead chubs (30), with lampreys (21), Johnny darters (17), red belly dace (12) and yellow perch (10) bringing the total of baitfish collected to 156, or 925 per mile of stream. There were no small (under 4 inches) trout present.

Collecting in the same stream, but downstream from its confluence with a much cooler trout stream, the increase in water quality was reflected in the composition of baitfish. Here creek chubs, sculpins and Johnny darters predominated, with hornyhead chubs, fathead minnows, red belly dace and lampreys present in smaller numbers. There were also a few trout under 4 inches. Gone were the "marginal" indicators such as mud minnows, black bullheads and tadpole madtoms.

In contrast to most other ecosystems, a high diversity of baitfish in a trout stream doesn't indicate water quality. Instead, the drop in the number of species of baitfish was a plus as far as a trout fishery was concerned.

To the top of the next column
Sculpins, the dominant or near-dominant baitfish in better Midwest trout waters, lack swim bladders and hence they are more or less confined to hunkering down on the stream bed. Against the pebbles of a riffle area, their mottled coloration renders them very difficult to see and they like to use their monstrous pectoral fins to help hold them against the bottom or against rocks.

With its huge head and mouth, no one every called a sculpin graceful and the common imitations, such as the Muddler Minnow, Wool-head Sculpin, or Dave's Sculpin, reflect this "mostly head" configuration. Sculpin imitations are available commercially tied from a #10 hook size to a #2; nothing is stopping you from tying a larger one, however. If it helps, the little fellow in the photo, in fact, is 3 1/2" long. And to make things easy for the fly tier, there are only two very similar species of sculpins, the slimy and the mottled sculpin, in Midwest streams.

With darters, on the other hand, normally staid Dame Nature went a bit berserk, both in the number of species she created and in coloration, particularly of the males during the spring breeding season. The black-and-white photo of the Johnny darter can't even hint at the incredible rainbow of coloration seen in the more than 140 species of darters in North America.

See if your library has The American Darters by R. A. Kuehne and R. W. Barbour. The color plates in this book of more than 100 darter species will blow you away. In contrast to the stocky sculpins, Midwest darters (with over a dozen species in Midwest trout streams) are slender and, one could say, graceful. They commonly rest in shallow riffle areas, often with their bodies slightly bent, where they feed on small insect larvae. Try to catch one with your hands--you'll see why it is called a "darter." Like sculpins, darters have no (or at best a very small) swim bladder, and hence they also spend most of the time on the bottom. So that,
obviously, is where your imitation belongs--stripped along the bottom, preferably next to some likely cover where a trophy trout is lying. Don't expect a sipping rise, either, from the trout--you're not using a #22 BWO imitation.

Baitfish.
Any month of the year.
Only one tail.
And big trout love 'em--give streamers a try next season, day or night.

Dean Hansen has a Ph. D. in aquatic entomology and is a regular columnist with Midwest Fly Fishing. This article appeared in the December issue of MFF.
copyright Midwest Fly Fishing Magazine 1999