I don't know that the least chub is the smallest native fish. Is it?
-- Jay DeLong Olympia, WA
Just Minnows by Laurence Pringle
The pond just over the hill had all the frogs, newts, and painted turtles a boy could want. But it dried up at times, or came close to it, so there were no fish. For fishing, my brother and I walked-- and later, hiked-- a couple of miles to a creek, or "crick," as our family and most other folks in rural western New York said.
In places the stream was narrow enough to jump across, which we sometimes did as we fished our way downstream. We had worms for bait. Basic tackle was a willow stick about five feet long, a length of string, and a bent pin. Sometimes we made bobbers from the spherical galls that form on goldenrod stems.
Catching a few fish was important in ways we felt but did not understand; it was an early step along the path toward success and acceptance in the fishing-hunting culture in which we lived. All we knew, of course, was that it was fun, fishing along a meandering creek on a summer day, with a mysterious tang in the air. Many years passed before I learned that the pungent odor came from lush growths of spearmint along the bank. Even later I learned about the fish.
"Just minnows" I said if someone asked about the catch. But there were two kinds of fish--minnows and chubs, my father called them if we took them home in a bucket. (He sometimes used them for bass or pike bait.) Actually, both kinds were minnows. The chubs we caught up to seven inches long in that stream, were creek chubs (Semotilus atromoculatus), a kind of minnow. The others were blacknose dace (Rhinichthys atratulus), another member of the minnow family. No doubt there were other kinds of dace in that creek, and maybe some shiners. Chubs, dace, minnows, shiners--they're all in the minnow family. Cyprinidae, the largest fish family on Earth, two hundred species strong in the United States.
A roll call of the cyprinids yields great diversity and some surprises. Goldfish, carp, and tench, for example, are in the family Cyprinidae, though most ichthyologists refuse to call them minnows. True minnows have scaleless heads, a few large teeth on bones in their throats (no teeth in their mouths), and a single dorsal fin supported by less than ten flexible rays. A few cyprinids have a pair of hard rays in that fin, but otherwise the diverse members of the minnow family conform to these basics.
Beyond this, beware of generalizations. Take the expression "minnow size" for example. Most people believe that all minnows are small fish, no more than three to six inches long. Compounding that error, people often apply the name minnow to young pike, perch, bass, and other species that grow to he large fish, and also to such little fishes as darters and to others called mudminnows, topminnows and sheepshead minnow. None of these are minnows. Among the true minnows, "minnow size" covers a range from the inch-and-a-half least chub of Utah--the smallest native fish in North America--to the six-foot-long Colorado squawfish. (Nowadays, however, a squawfish three feet in length is exceptional. Survival of this endangered minnow depends on protection of some remaining habitat in the larger rivers of the Southwest and a hatchery-rearing and restocking program conducted by the U.S. Fish and Wildlife Service.)
Though the difference between one minnow species and another may at times be obvious only to an ichthyologist, the variety of North American habitats has given us an extraordinarily rich minnow fauna. This becomes apparent when you begin reading a list of minnow common names. The scientific names are fun too: savor Notropis boops (bigeye shiner) on your tongue; sink your teeth into Exoglossum maxillingua (cutups minnow).
Imagine a poetry reading. with the sonorous tones of Galway Kinnell or Paul Metcalf, or the hard-driving chants of Patti Smith, as selections are read from the American Fisheries Society's "List of Common and Scientific Names of Fishes from the United States and Canada":
Devils River minnow, comely shiner, bonytail. Stargazing minnow, desert dace, peamouth. Cutlips minnow, bigeye shiner. Hardhead. Warpaint shiner, silverjaw minnow, woundfin. Little Colorado spinedace. Ohoopee shiner, stoneroller, ghost shiner. Flame chub, rosyside dace.
Hidden in the poetry of minnow names are clues to their appearance, habits, and geographical location. Stonerollers push pebbles with their snouts while digging nests in riffles. The bigeye shiner has large eyes appropriate to an animal that pursues prey in clear water and that sometimes leaps several inches above water after flying insects. And the peamouth of the Snake River and its tributaries is named for its tiny mouth. A good many members of the minnow clan are named for the appearance of their mouths and heads: chiselmouth, bigmouth, and suckermouth; thicklip, redlip, cutups, and fatlips; roundnose, pugnose, longnose, sharpnose, bluntnose, blacknose, and hluenose; bluehead, greenhead, hornyhead, bullhead, burrhead, and even fathead.
Though minnow faunas are poor in the Far West, most states have a few dozen species, and those in the Mississippi River Basin may have a hundred or more. The coexistence of several species in one stream or body of water means that each kind has a different ecological niche. Complete competitors cannot coexist, so two or more species living in the same place must differ in some ways. The differences often aren't apparent, and biologists sometimes go to great lengths to determine how the resources of a plant- animal community are shared.
Using scuba and seines, Peter Moyle (now of the University of California at Davis) studied minnows of a small Minnesota lake in the mid-1960s. Three kinds of minnows had well-established populations in the lake's shallows, and Moyle's research showed how they coexisted. Mimic shiners fed on invertebrates near the surface and in the midwater zone; bluntnose minnows ate invertebrates and algae from aquatic plants and the lake bottom; common shiners were opportunistic feeders, eating whatever was most available anywhere from the surface to the bottom. Moyle also found that the three species had different feeding schedules, breeding times, and breeding places. With the resources of food, time, and space divided among these fishes there was little apparent competition. Though there were other potential competitors in the lake--blacknose shiners, blackchin shiners, and fathead minnows--they were limited to a fringe existence in the face of competition from the well-established species.
Moyle's study was remarkable in part because most resource-partitioning investigations have been conducted on dry land with more easily observed creatures, and also because so little has been learned about minnows in general. Ichthyology journals are rich with details about trout, bass, salmon, and other game fish. Articles about minnows, one vital link down the food chain, appear infrequently; they almost invariably begin with a remark about the scarcity of knowledge about the minnow under investigation.
Finding out what minnows eat involves catching them and dissecting their guts, but some aspects of their lives can he observed more easily by patient watching of a clear stream from its bank or a bridge. From such a place you might see a cutlips minnow carry pebbles in its mouth to build a circular nest about eighteen inches across. Fallfish, which are eighteen-inch long dace, make the largest minnow nests, up to three feet high and six feet across. They carry stones up to three inches in diameter in their mouths.
Most chubs also build nests. In Michigan, a biologist watched as a male river chub built a nest about seven inches high and more than three feet across. Then he waded into the stream and carefully undid the chub's work in order to count the stones and pebbles. There were 7,050, weighing a total of 88 pounds. A single six-inch river chub had moved them all in less than thirty hours, traveling an estimated sixteen miles in the process.
Ordinarily a river chub has even more stone-carrying to do once the basic nest structure is complete. It digs a trough in the nest, a female enters, spawning occurs, then the male quickly fills the trough with stones. Another trough is dug by the male, and the process is repeated, over and over. The fertilized eggs are aerated as water flows among the stones of the nest.
Spawning season is a fine time for fish-watching. The males of territorial species develop their most intense coloration, though few rival the dazzling scarlet of the northern redbelly dace. At the peak of the spawning season a chub nest may attract a half-dozen species of mating minnows. Suckers and darters often are present too, eating any fish eggs they can find. Some minnows try to chase scavengers away; and also defend their breeding territories. Male fathead minnows chase all intruders. In fact, only the most persistent and aggressive females are able to reach the nest site and release their eggs, whereupon they are fertilized by the male. (When the eggs are down, the male fathead is no fathead.)
A few years ago, ichthyologists William and Cynthia Gale watched male spotfin shiners defending breeding territories among rocks in the Susquehanna River in Pennsylvania. They saw male shiners grab the pelvic or anal fin of an opponent and drag it away from the nest site. Sometimes two males would grab each other's pelvic fin, then whirl in a circle, faster and faster, until they were a blur.
If only we were smaller and better adapted to life underwater, then we could pack a lunch and a field guide, slip into a stream, and watch these fertility rites in clear detail. Imagine several species of minnows maneuvering around one nest, the males flashing their bright colors, the water carrying a euphorious chorus of trills, purrs, chirps, and other minnow calls. Emerging from our aquatic field trip, perhaps with a new dace or shiner added to our life list, we would never dream of calling these fishes "just minnows."
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