TAKEOFF
BASS SCIENCE
BASS UNDER ICE
i
WheRe theY Go in WinteR up noRth
Where they go
“one of the most surpris-
ing things we found while we
were following the tagged
bass is that they moved a
whole lot more than we
thought they would,” hasler
says. “obviously, they swim a
whole lot slower, but bass in
our study routinely circum-
navigated our small sample
lake during the course of a
single day.”
n the northern reaches of the coun-
try, the bass season is put to bed
right around the time ice starts to
form on the lakes, ponds and reservoirs
that dot the region. for species such as
walleyes, northern pike and various
types of panfish, the hard-water fishing
season is just getting ramped up. Yet, for
whatever reason, bass seem to pull a
disappearing act as soon as the water
freezes.
sure, bass are caught each winter by
ice anglers, but those catches are almost
always incidental in nature, and outside
of a couple of unique regional hot spots
it’s difficult to consistently target and
catch bass through the ice.
so what gives? Why do bass go the
way of the ghost once the ice forms?
dr. caleb hasler, a fisheries biologist
with the university of illinois, is one of
the few scientists on the planet to inves-
tigate bass behavior under the ice. in a
recent study, he and his fellow
researchers tracked tagged largemouth
bass under the ice using radio telemetry,
and their findings shed light on bass
behavior after the big freeze.
By TJ Maglio
Though bass are often caught by accident through the ice, they’re normally very difficult to consistently
target. What gives?
Bass in halser’s study
also routinely suspended a
meter or two beneath the
ice sheet and just cruised
around the lake. it’s not clear
whether these fish were
feeding, or just taking advan-
tage of preferable conditions
at that level.
Where they don’t
“We also studied oxygen
levels throughout our lake,
What About Smallmouth bass?
as they are known to plum-
met during hard winters,”
hasler says. “not surprising-
ly, the bass avoided the
areas that had the lowest
oxygen levels.”
areas they avoided were
shallow, grassy portions of
the lake and extremely deep
locations where, presum-
ably, decomposition was
occurring. decomposition of
vegetation depletes oxygen,
the vast majority of bass catches under the ice each year are of the green variety.
outside of a couple of unique locations, catching a smallmouth bass through the ice is a
feat that most ice fishermen go their entire lives without witnessing. a big factor in this is
that they’re likely not around. Research in canada showed that smallmouth bass tend to
winter by the hundreds in tiny, specific “holes,” vastly reducing the likelihood of an angler
finding them.
“smallmouth bass are also known to be much more dormant during the winter than
largemouth bass,” hasler says. “this dramatically reduces the number of feeding opportu-
nities they encounter each winter, and is a likely reason that so few are caught by anglers.”
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so areas with the most vege-
tation in the summer typical-
ly have the lowest oxygen
levels in the winter, with the
exeption of early ice season,
before the grass dies.
do they eat?
past studies have shown
that in laboratory conditions
bass essentially stop eating
when water temperatures
dip below 45 degrees, but in
the real world thousands of
bass are caught each year in
water colder than this.
“Wild populations of bass
acclimatize to the cold
weather over time,” hasler
says. “if you study northern
bass’ annuli [growth rings on
scales], they show that most
individuals experience at
least some growth during
the winter.”
flWfishing.Com i january 2017