Fish Facts: Bluegill (Lepomis macrochirus)

Most of us have an early memory of reeling in bluegills from a local pond, using just a worm or some equally homey bait. The fact that the species, Lepomis macrochirus, goes by many different names—bream, blue bream, sun perch, blue sunfish, copperhead, copperbelly, roach—is a testament to its popularity in many regions of the country. But any avid bluegill angler will tell you that the big ones, known as “bulls,” are as wary and hard to catch as any trout.

Range and Habitat

The original range of the bluegill covers most of the eastern half of the U.S.—stretching from Quebec to northeastern Mexico, but they did not inhabit the coastal states north of Virginia. Because they are so prized as both a sport fish and a source of food, they were introduced throughout the country and now swim in every state except Alaska. They have also been exported to other parts of the world, where it is sometimes seen as an invasive species and a pest. Bluegills given as a gift by Chicago mayor Richard Daley to the emperor of Japan escaped a containment pond and have wreaked havoc with native species.

Bluegills can thrive in a wide variety of habitats, and they are found in lakes, ponds, and slow-moving rivers—especially those with fertile water containing lots of microinvertebrates. They prefer the same weedy habitat where you’re likely to find bass, with the larger fish holding in deeper water. In fact, predation by bass is often seen as a vital component of a healthy population of bluegills, especially larger ones.

In the spring, they spawn in colonies, digging circular, crater-like redds in sand or gravel. Bluegills reproduce rapidly—females can spawn up to nine times a season—a characteristic that makes them a good food fish but which often leads to overpopulation and stunted adults when there is no harvest. However, overfishing will also lead to a reduction in the average size of the fish.

Ounce-for-ounce, bluegills fight harder than most game fish, so even little’uns will scrap.
Photo by Beau Thebault

Tactics and Flies

The world-record bluegill, a 4-pound 12-ounce bull, was taken from Alabama’s Ketona Lake by T.S. Hudson in 1950. Although average bluegills feed frequently on the surface, making them susceptible to small poppers and sliders, the biggest specimens inhabit deeper water—often as deep as 30 feet—and require much more sophisticated tactics. All bluegills eat insects and worms, but the big boys will also feast on small crayfish and minnows. There are many different patterns designed to catch bluegills. To catch these big ones, try a slow-sinking Bully Bluegill Spider, a black leech, or a small streamer. For sheer fun, it’s hard to beat catching bluegills on the surface, using a small slider or popper.

The Bully Bluegill Spider is a sinking fly that can be used as a dropper off a popper.
Photo via orvis.com

Canaries in the Coal Mine

Although bluegills live in many different water types, they are quite sensitive to water quality, and scientists have developed methods for exploiting this characteristic. In fact, the panfish are used to protect millions of Americans from a terrorist attack on drinking-water supplies. The U.S. Army originally developed the 1090 Intelligent BioMonitoring System—which monitors the behavior of eight bluegills swimming in tanks through which water is pumped—to keep tabs on groundwater quality. But since the attacks of 9/11, the fish have been protecting residents of New York City, as well as those of other major cities. Electrodes mounted on the fish tank read the fish’s respiratory behavior, and complex software determines when the fish experience distress.