Jed Pearson, Indiana Division of Fish and Wildlife
Bluegills, Lepomis macrochirus, are the most abundant and most important fish in northern Indiana natural lakes. Based on standardized data compiled by the Division of Fish and Wildlife at 197 lakes since the 1980s, bluegills averaged 45% of the number and 15% of the weight of fish collected in 387 fish population surveys. Electrofishing catch rates in June from 219 surveys at 125 lakes averaged 86/15-minutes of sampling (inter-quartile range: 36-123), including 8/15-minutes of 7-inch and larger bluegills. Although overall electrofishing catch rates declined since the 1980s (p = 0.02), catch rates of 7-inch and larger bluegills remained steady (p = 0.16) while the proportion of 7-inch and larger bluegills increased from 7% to 19% (p = 0.03). Bluegill growth rates also remained steady (p = 0.37) with age-4 bluegills averaging 6.2 inches long. Based on 118 angler surveys conducted at 52 lakes since the 1980s, the percentage of anglers who targeted bluegills declined from 47% to 35% (p = 0.03) but fishing effort directed at catching bluegills remained constant (p = 0.90), averaging 25 hours/100 acres/day. The harvest rate by anglers who targeted bluegills remained constant at 1.5/hour of bluegill fishing (p = 0.85) and harvest rate of 7-inch and larger bluegills remained steady at 0.7/hour (p = 0.38). The results document long-term status and trends of bluegill populations and bluegill fishing at Indiana natural lakes.
Comments: I have to admit that I found the results of this analysis fairly surprising. I expected a bigger decline in the overall bluegill fishery across that many lakes. Truly big bluegills are one of the easiest fisheries to decimate, in part by pressure, lax regulations, and the traditional 'harvesting' nature of panfishermen. My speculation is that perhaps the worst of the damage might have already been done to the fisheries by the time they started tracking the bluegill metrics in the 80's. I base this on some of the data that has come out of Minnesota. In Minnesota, DNR fisheries research biologists Donald Olson and Paul Cunningham analyzed 113,845 entries from 1930 until 1987 that were part of the detailed records maintained for the Fuller's Hardware Big Fish contest. Their work documented the decline of most all species of big fish over time. Included in their findings was that the weight of the average bluegill shrank by 25 percent from 1970 to 1987.
Regardless, I'm much more protective of a great bluegill lake than of any other fishery in the state. I'll share good crappie and good bass lakes, but really good bluegill lakes never get mentioned unless they're already restricted due to being private waters. Even then....
For further reading, see: "Cult of the Bluegills"