TAKEOFF
BASS SCIENCE
THE DOWN-LOW ON DO
A
hoW dissolved oXYGen levels influence Bass BehavioR
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nglers analyze factors such as water temperature, clar-
ity and current every day while on the water. they rou-
tinely spout classic lines such as “dark water, dark lures,”
and talk about how the water needs to get into the low 60s
before the topwater bite is any good.
But does anyone have a bit of homespun wisdom about
dissolved oxygen?
dissolved oxygen, or do, is every bit as important – and
likely more – as all those other factors in the location and activ-
ity level of bass, but anglers seldom think about it.
other than the presence or absence of water, dissolved
oxygen is the second-most important factor in answering the
simple question of “can a bass live here or not?” if there’s not
enough do in the water, bass won’t survive.
Shallow backwaters cut off from current and wave action often lack enough dissolved oxygen for bass to reside there in summer, but in the case of
John Cox’s winning backwater at the 2016 Cup, inflow and aquatic vegetation kept the area oxygenated and rich with life.
By TJ Maglio
here’s how dissolved oxygen affects bass, and how paying
attention to it can help you catch more and bigger bass.
How Much do Bass Need?
dissolved oxygen is measured in milligrams per liter (mg/l),
and normal dissolved oxygen levels range between zero and
15 mg/l. Bass and other warmwater species prefer do levels
above about 5 mg/l, and start to avoid areas as do levels get
below 3 mg/l. they begin to suffer physiological damage and
death once do levels go below 2 mg/l.
coldwater species such as trout and salmon typically
require much higher do levels, and some rough fish such as
bowfins, fathead minnows and carp can tolerate levels below 2
mg/l for extended periods of time.
FLWFISHING.COM I JULY 2018