Bluegills are are related to the perches and are members of the family Centrarchidae, which includes large- and small-mouth bass. Centrarchids are an ancient North American speciality; found coast-to-coast and from Mexico to above the Arctic Circle. They have survived the dinosaurs and have been transplanted by humans to all parts of the globe. Bluegills (and their cousins the basses) are native to the Mississippi River drainage system and were brought to the Atlantic rivers in the late 19th century. Bass were taken to California in the water tenders of steam locomotives almost as soon as the Golden Spike was driven. Now that the Potomac has been cleaned up, thanks to gazillions of your tax dollars (thanks!)and the introduction of an aquatic weed that thrives in polluted water, it has become a major stop on the Pro Bass Fishing Tour. Yes, there are professional bass anglers. One of the cable channels carries pro-bassin' programs. I guess it's entertainment, but watching someone else fish is slightly more boring than watching paint dry.
Bluegills are colonial breeders, meaning all the bluegills in the pond will be nesting at the same time. From about late June until now, if you haunt ponds, lakes, slow moving creeks, and other assorted wetland areas, you will see what looks like a series of small bomb craters lining the banks in water about a foot or so deep and going out into deeper water. These are bluegill nests. Given the limited area for nesting, competition is fierce. Males stake out hexagonal territories, build a round depression in the bottom, and stand guard with all their breeding colors showing. A bluegill in breeding fettle is as pretty as any exotic fish from the rain forests that you may see in the local aquarium store. Males build and guard their nests fiercely; they will attack anything encroaching into their territory and a small lure trolled near the surface is sure to get a strike. Females flit from nest to nest, sizing up the males and deigning to lay a few eggs in whatever nest whose male strikes their fancy. One female can produce up to 50,000 eggs, but she will distribute them around several nests, mating with several males. A single nest can hold up to the same number of eggs produced by a single female, so the numbers even out. Eggs hatch in about a week, and the young spend their first year or so hiding in weeds or submerged brush. Two- and three-year olds begin breeding and five-year old bluegills are rare. Nests near the center of the colony are preferred and males compete for them, the bigger guys ousting the smaller ones. Nests on the edges are more heavily preyed upon by catfish and surprisingly, snails, which may account for up to half the egg losses. A closely related sunfish, the pumkinseed, is a solitary nester. Pumkinseeds feed on snails and may cruise around the bluegill colony hoping to pick up a quick snack.
It may seem that the big alpha males have all the advantages in colonial nesting, but they are not alone in the sweepstakes to get their genes out to the next generation. Aside from other alpha males constantly patrolling the colony, hoping to take over an established nest(any male you catch will be almost instantly replaced), two other male types; satellites and sneakers, also lurk the shallows. Satellites are males, but with female coloration and some their behaviors. When a couple begin to go into their breeding behavior, a satellite will come into the nest and join in, mimicking the female. This is the stuff of Penthouse Letters for the alpha male and he happily and blindly sets forth. When the real female releases her eggs and the alpha male begins to fertilize them, the satellite also releases a cloud of milt to mix in. Up to half the eggs in a nest may be fathered by satellites. Unless the sneakers get into the act as well. Sneakers are dwarf males, hanging around the edges of territories, looking inconspicuous, and staying out of trouble. At the right moment, a sneaker will dash in upon the happy couple, release his milt, and be gone before the alpha male realizes what's happening.
Bluegill population genetics are such that neither satellites nor sneakers will ever get too abundant; both populations are dependent, almost parasitic on a good number of territorial alpha males who stake out territories and defend the nests, eggs, and young. Even so, next time you take a kid fishing, don't forget to ask your catch "Who's your daddy?"
