Locating bluegill in a big shallow lake

[Glen Wagley]

I mainly fish Utah Lake in Utah (of course!). It is a large (96900 acres) body of water but the average depth of the lake is only 10 feet. Common carp were introduced years and years ago by settlers from Europe who wanted them as a food fish. Unfortunately, the carp have multiplied to such a state that they make up the largest part of the lake's biomass. An effort has been in place for the last couple of years to reduce the population of carp by 75% and it is working. Without going into the nitty gritty, the downside of the carp is that they absolutely nuke a lot of the underwater vegetation. Shallow lake plus little vegetation to hold the sediment in place causes Utah Lake to look like chocolate soup on windy days. The upside to the lake is the success of several warm water species namely channel catfish, bullhead catfish, largemouth bass, white bass, walleye, yellow perch, bluegill, and black crappie.
There are a few harbors on the lake and large parts of the lake shore are ringed with cattails and other vegetation.
Now for my plight. I do well finding and catching bluegill through the ice and during the spring. The bluegill start to spawn around the first week of June and the fishing is pretty nuts for the entire month. They disappear the first week of July. I can find a few in the pre-spawn areas which is typically around dock structure but after mid-July, I won't find the gills again until the water really cools off as they move into their winter pattern before ice up.
I would imagine that the gills would move out to deeper water during mid to late summer and into fall before moving back into the harbors for ice up. I forgot to mention that there are a few natural warm springs that feed the lake as well as two rivers and a couple of creeks feeding the lake. I've tried fishing the reed lines around the lake but the water doesn't seem deep enough for the gills to hold there. It seems logical to me that they would be in/around reed beds since the freshwater invertebrates and other bugs would be there as well. I would target the warm springs but one of the most well known springs feeds a private harbor that I have no access to. I doubt all the bluegill head to that one spring for warmth. Anyhow, if anyone had any experience fishing a large relatively structureless lake (think of a huge mud bowl with plants around the edges) or could even give me some new ideas as to where I should look, I would appreciate it. I really can't complain too much about the quantity or quality of bluegill in the lake. There have been 10 inchers caught there (I've caught several 8 inchers and a few 9 inchers that are thick and ANGRY) and I'm sure there are bigger ones as bluegill is a species that is only targeted by very few fishermen in this area. Any suggestions would be appreciated. It could be that my style of fishing from a float tube is the limiting factor to my success. I'm not sure yet! :-)