May 2023 • Nebraskaland 39
Biologists may stock fewer bluegills in these waters in the
future and see if growth rates of the younger fi sh increase.
At age 3 and beyond, fi sh feed on macroinvertebrates,
primarily aquatic insects. These critters thrive in timber and
terrestrial vegetation that is fl ooded when reservoirs fi ll, and
also in aquatic vegetation that sprouts in both waters. That
means there is plenty of habitat to produce food for the fi sh,
and plenty to go around.
Those habitats decline as reservoirs age, and fi sh growth
slows. At Swan 57, bluegills rarely, if ever, reach 8 inches.
With common carp present, no aquatic vegetation, and poor
water quality, there are few insects for them to eat. "They're
a sight-feeding fi sh, too, and its super-turbid water, so they
can hardly see the food they're trying to get," Perrion said.
The fi ndings reinforce the precept behind Game and
Parks' Aquatic Habitat Program. "The overarching theme
is water quality," said Aaron Blank, fi sheries supervisor in
southeastern Nebraska. "If you have good water quality,
you're going to have good bluegill growth. But usually, the
bluegill fi shery is never going to be better than it is in those
fi rst few years."
The data also showed once bluegills hit 8 inches, no
matter the age of the reservoir, growth plateaus. That might
be another density-related bottleneck, with many fi sh
competing for the same food resource. It may also be that
the genetically superior, faster-growing fi sh are the fi rst
to be harvested, leaving slower-growing fi sh to reproduce.
Flanagan Lake will be the fi rst test in the state of an 8-inch
maximum length limit on bluegills, something biologists
believe will lead to more 9-inch and even 10-inch Master
Angler bluegills.
"If we're producing 8-inch bluegills, we're pretty darned
happy," Blank said. "That's what anglers prefer. I always tell
people to keep what you're catching the most of. If for every
15 7-inchers you're catching, you get one 8-incher, just keep
some 7 inchers."
And that, he said, could lead to more hard-fi ghting, big
bluegills.
N
Jerry Kane of Lincoln holds an 8-inch bluegill, the length
many anglers prefer to keep.
Matthew Perrion uses tweezers to remove an otolith from
a bluegill, the growth rings on which show it to be a 3-year-
old fi sh. As part of their growth study, biologists aged
bluegills using both otoliths and scales, and found they
often underestimated the age of older fi sh using scales. The
improved accuracy will make it their standard for aging
bluegills and other panfi sh.
