Bluegills!

Thunder rumbled in the distance as the setting sun illuminated cumulonimbus clouds towering above the lakeshore. My parents and I paddled our canoe slowly around the weed beds on the perimeter of the lake, “heading in” we called it, while still casting leisurely among the water lilies and rushes. We already had about eight hand-sized bluegills on a stringer. None were trophies, but all would be tasty fillets.

As the old concrete boat ramp appeared through the weeds, I made one last cast. Plunk! My bobber dropped just this side of a half-sunken log. With a click and whirr I began reeling in my line. Not two feet from the log, I had a hit! I set the hook and reeled quickly, surprised at the fight on the other end. “It must be a bass,” I exclaimed, until I saw the big roundish body and bright yellow belly come to the surface. This female bluegill was a very respectable nine-inches or so. She went on the stringer as we drifted into the landing. It was the perfect end to an evening on the water.

Panfish, including bluegills, crappies, and perch, are Wisconsinites’ favorite fish to catch. Kids, and kids-at-heart, get an easy thrill when the bobber dives under and the fight begins. Even catching the fingerlings is fun, and jokes about the “biggest fish of the day,” never seem to grow old.

The Museum recently hosted a lecture about bluegills by Dave Neuswanger, fisheries biologist for the DNR. He has been putting together a literature review of scientific papers written about bluegills. Of course, he is gathering the information for use it in fisheries management, but he uncovered some strange facts about these common fish, too.

Did you know that their scientific name, Lepomis macrochirus, means “large hand,” and refers to their relatively large pectoral fin? Male bluegills also have a large earflap and orange-to-coppery breast, while the females have a normal-size earflap and a bright yellow breast. Bluegills do hybridize with their cousins the pumpkinseeds, but it only works with a male bluegill and a female pumpkinseed, not the other way around.

Male bluegills build their nests by swishing and scooping fine sediments out from around bigger stones. Bluegills prefer gravel to sand or muck, but they will make do with many types of substrates. Larger spaces between the pieces of gravel allow fresh water and oxygen to flow among the eggs, and help protect the eggs from predators.

Dozens of males build their nests in a cluster. Nests on the inside of a colony tend to be more successful than nests on the perimeter. Males must defend the nest from snails, crayfish, black bullheads, and even other bluegills! Younger, smaller bluegills are a significant source of mortality for bluegill larvae after they leave the nest. That’s not the only weird nesting behavior they have, either!

Males build and defend a nest, and females come to them. The pair will swim side-by-side in a circle-dance, each emitting their own reproductive products. One female may visit 2-3 different nests to lay all her eggs. Sometimes a precocious male, who is younger but matured faster, will hover around the nest and change colors to closely match the female already engaged in mating. Then he will join the mating dance! The parental male who built the nest will think he’s got two girls, when really the younger male is fertilizing some of the eggs. Other times, precocious males called “sneakers” will just dart in and give a good squirt, fertilizing as many eggs as they can on short notice!

No matter how they do it, I am grateful that bluegills have plenty of babies. That means there are more for you and me to catch and eat!

For over 44 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 13470 County Highway M. The new exhibit, STAR POWER: Energy from the Sun, opened in May 2012 and will remain open until April, 2013. Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com/