Small members of the perch family live their lives on the bottoms of many Illinois streams— and go largely unnoticed.

Story By Rob Miller Photos By William N. Roston

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s many amateur aquar - umn, but allows them to stay put in Darters feed on a variety of items, including ists will attest, perhaps fast-moving water, one of their favorite small crustaceans, midges, mayflies and crayfish. some of the most beau - habitats. Logperch ( Percina caprodes ) can use their tiful and unique fishes Darters spend the majority of their are found not in some lives in relative obscurity on the stream snout to turn over rocks to find food and will do Afaraway tropical paradise, but in streams bottom, using their coloration to blend A so quite readily in an aquarium setting. running through the Prairie State. into their surroundings and avoid pre - Diminutive in size, this largely dation. Supported by their front fins, unknown group of fish is second only to darters often remain motionless on the darters which have pallid coloration and the minnow family in diversity and abun - bottom, and when alarmed, they dart a preference for sand; and Etheostoma , dance. They occupy a wide variety of off quickly to the nearest cover, hence a large and diverse genus with 16 habitat types, but many species have their name. species occurring in Illinois. specialized requirements and are sensi - Darters are relatively restricted in While most darter species require tive to degradation. Related to the wall - their distribution in North America, specific habitat conditions—swamps, eye, sauger and yellow perch, which are occurring primarily in the Mississippi sloughs, backwater areas or specific more familiar to most anglers, this group River system. Few darter species are sizes of riffles—some are generalists of fishes is referred to as the darters. found west of the Continental Divide. and can be found in slow-moving water Although predominantly stream- The largest concentration of darter and larger streams throughout Illinois. dwelling fish, some darters can be species occurs in the eastern half of A few species are somewhat tolerant found in lakes and wetlands. Unlike Tennessee and northern Alabama. Illi - to siltation and pollution. most species, darters either completely nois is home to three genera: Percina , Life history characteristics are quite lack or have an underdeveloped swim which have five species in Illinois, are varied among the darter species. The bladder—an adaptation that prohibits blandly-colored darters with a large anal life expectancy for most darter species them from suspending in the water col - fin; Ammocrypta , comprised of just two in Illinois averages three years, with few species in Illinois, are long, slender surviving past four years. The least 18 / Outdoor Illinois May 2005 darter ( E. microperca ), growing to a ing spawning, remaining so for 20 to maximum length of just 1.5 inches, 30 minutes. rarely lives beyond two years. In con - Depending on the species, female trast, logperch ( P. caprodes ) can reach darters can produce anywhere from 7 inches and often live beyond three just a few to several hundred eggs. years. In some systems, logperch are a The extremely territorial male spottail mainstay in the diet of walleye which darter ( E. squamiceps ) will court sever - undoubtedly decreases their chances of al females, who will then deposit as Johnny darter living a long life and may explain their many as 1,500 eggs on the underside tendency to bury themselves up to their of a stone. eyes in sand. In 68-degree Fahrenheit water, darter Most darters become mature in one eggs hatch in about eight days. The year and spawn in the spring. While males of some species zealously guard some darters retain their color through - their nests, while little parental care is out the year, these pigments become provided for others, such as Iowa much more pronounced in males during darters ( E. exile ), which attach their the spawning season and result in spec - eggs to plant material. Once the eggs of tacular looking fish. Brilliant scarlets, orangethroat darters ( E. spectabile ) Orangethroat darter blues and greens adorn the fins and hatch, the fry have been known to move bodies of these colorful fish, putting into smallmouth bass nests and benefit them in league with many tropical from the protection provided by the species—even if only for a short period guardian male bass. of time each year. For the most part, darters are intoler - Darters either bury eggs in the sand ant of pollution and other environmental or attach them to rocks, logs or some changes and can be considered as a other objects. The female bluebreast barometer of water and stream quality. darter ( E. camurum ), an extremely The Department of Natural rare species in Illinois, will partially Resources utilizes the Index of Biotic bury herself headfirst in the gravel dur - Integrity (IBI) to rate Illinois streams. Banded darter One component of the IBI is the number of darters present—the more darters the In addition to their increased coloration during The johnny darter ( Etheostoma nigrum ), is tolerant higher the quality rating for a given the spawning season, males of some species have of slow-moving water and can be found through - stream section. Unfortunately, extensive special adaptations useful during this period. channelization and other forms of degra - out the state. Orangethroat darters ( E. spectabile ) Slough darters ( Etheostoma gracile ) develop dation have caused several darter are similar in appearance to rainbow darters protuberances on their chins to stimulate females. species to be extirpated from Illinois, (E. caeruleum ) and both can be found in the same and others to be listed as state-endan - Other species have modified knobs on the tips stream. Orangethroats will reside in small, gered or state-threatened. of their dorsal fins for preparing the spawning Darters are unknown to most people shallow riffles and rainbows in deeper riffles. site and attracting females. but play a vital role in the ecosystem of The banded darter ( E. zonale ) occurs in northern Illinois and is one of the few darters somewhat tolerant to siltation and pollution.

our aquatic environments. The next time you’re fishing your favorite smallie stream or wading in the creek, take a closer look at the rocky substrate. You just might get a quick glimpse of a truly marvelous little fish, just before it darts under another rock.

Rob Miller is a DNR fisheries biologist based in the Yorkville office. Slough darter

May 2005 Outdoor Illinois / 19