FISHING
CONSERVATION
BASS METABOLISM BASICS
BALANCING ENERGY NEEDS, SURPLUS AND OPPORTUNITY
Y
ou hear the word metabolism thrown around a lot
these days.
human metabolism is studied heavily in the nutrition
and fitness industry, with people throwing around buzz-
words like “glycemic index” and television commercials
pitching fad diets that promote “ketosis” and “intermittent
fasting.” in bass fishing, anglers also frequently talk about
metabolism; not in a kitschy sense like with people, but in
the context of how it affects bass feeding activity and,
thus, catch rates.
as frequently as anglers talk about metabolism of fish,
however, few actually understand what it is or how it
affects bass activity, particularly in cold weather.
The Basics
at any given moment, a fish’s metabolic “cost” is pri-
marily dependent on the water temperature. in warm
water, bass’ muscles fire faster; they process oxygen
more efficiently, and can more efficiently chase and cap-
ture prey (higher income). the downside is they also need
a lot more of it (higher expenses). in cold water, bass
need to eat less to survive (lower expenses), but they are
in turn less active, have slower metabolic reactions and
exposure to suitable prey items is less frequent (lower
income).
so, if you’re a bass, would you rather be in a food-rich
environment with warm water but need to eat frequent-
ly? or would you prefer to be less active, but also not
need nearly as much food to sustain your functions?
good thing for bass they only have pea-sized brains
and don’t get to choose. in reality, bass and other fishes’
locations, activity patterns and many other factors essen-
tially boil down to them searching to balance those meta-
bolic needs.
Finding Balance
38
the above discussion is simplistic, but designed to get
you thinking about how complicated the study of metab-
olism gets when talking about a cold-blooded animal like
a bass.
Bass don’t feed heavily in extreme cold, but they will bite if the
situation is right.
FLWFISHING.COM I WINTer 2020
the textbook definition of metabolism is “the set of
life-sustaining chemical reactions found in all living organ-
isms.” at the base level, there are three textbook parts to
any organism’s metabolism:
1. the creation of energy from food.
2. the conversion of food/fuel to anatomical building
blocks such as proteins, fats and structural elements
(growth).
3. the elimination of waste.
it all sounds awful sciencey, right? a method i think
helps people to understand it is to think of metabolism
as a monthly financial budget. there’s an income, but
there are costs associated with living. at the end of any
period of time, add up the costs, and if they are less than
the inputs there is a surplus. in the financial analogy,
excess is savings in the bank, and any shortfalls must be
made up from prior savings. in the context of animal
metabolism, any surplus is stored as fat or used for
growth, and any shortfall must be made up with reserves.
this analogy holds extremely well for warm-blooded
(endothermic) creatures. however, it becomes less apt for
fish and other cold-blooded animals (ectotherms), which
is a concept scientists understand, but most anglers still
don’t.
for ectotherms such as reptiles, amphibians, bass and
other fish, as their environment changes, so does the
metabolic equation. to return to the budget analogy for a
second, imagine if, as it got colder in the winter, your rent
or mortgage decreased. that would dramatically change
the way you live. But what if, in addition to your bills
decreasing in the winter, your salary also decreased?
that’s kind of how bass metabolism works in winter.
By TJ Maglio