2/19/2001
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Article
I’m
Full
By
Charlie “Turk” Gierke ·
Croixsippi Fishing Guide Service
“But
it’s only wafer thin.” That’s the classic line from Monty
Python’s The Meaning of Life. The line is politely uttered by a
waiter to his rotund and very gluttonous customer. The same patron
who has just oinked down a spread that would feed a casino. At first
the consumer declines the offer, and then, with pant and shirt
buttons popping, takes the after dinner mint “swallows” and
explodes into tiny bits all over the restaurant. In the watery food
chain, when our finned friends have enough to eat, they push back
the plate and say no mas, enough. During times when the forage base
is abundant, anglers are the ones likely to go hungry. Fresh lively
leech on the hook or not, sorry - ol’marble eyes is full.
 Around
the third week in July last year, on the Mississippi and St. Croix
Rivers a few of the locals I know talked about the fish having sore
mouth-or other erroneous themes such as “fished out” or “lock
jaw”. However they forgot to mention the current year’s bumper
crop of shad and shiners, they seemed to be everywhere. It was
frustrating, because as the old saying goes “find the baitfish,
and you’ll find the walleyes.” Belly full of shad walleyes. It
was obnoxious, and plain hard not to see groups of baitfish grouped
up where ever your outboard brought you.
As
a fishing guide on the St. Croix and Mississippi, the lifecycle of
the rivers forage base has naturally been of interest to me, but
especially the last few years when the shad and shiners have been so
prevalent. So on a snowy January day I called, Mr. Dan Dieterman,
Lake City Area Office, Fisheries Specialist of the Minnesota
Department of Natural Resources, to get more info on Mr. Walleye’s
favorite menu items. Dieterman believed that in the Mississippi
River Lake Pepin area, that approximately 70% of the river’s
gamefish forage base is comprised of gizzard shad, emerald shiners,
and bullhead minnows.
The
bullhead minnow is not a young of year (yoy) bullhead but entirely
different minnow specie. Of the main three forage species the
gizzard shad has the highest population, and the gizzard shad
consists of approximately 35-40 % of the river’s entire forage
base alone.  Along
with the main three species, there are also yoy drum, carp, sucker,
some perch, (on the St. Croix - side note - remember where you’ve
caught perch on the Croix because that’s fall trophy eye country.)
crappies, sunfish, and 30 to 40 types of other minnow species, and
more.
The
main reason I dialed the DNR, was to find out about the high
population of forage in recent years. As it was explained to me,
shad typically do not live past one year. Their lifecycle starts
from hatch, near the end of May until early February, when they die.
In recent years the duration of winter has been shorter, and milder,
and has allowed more shad to live beyond one year. Though more are
living, still less than 1% of the entire population are likely
living past the typical one year cycle, and according to Dieterman
of these fish, some can reach 17-18 inches and may be up to three
years old.
 Other
factors affect yoy shad and other forage species survival. High or
low nutrient inputs from spring flows are a key link in the food
chain. Last years spring run off provided ample nutrients to the
forage base and the macro invertebrate. The river is running
clearer, maybe as a result of the zebra mussel population. There has
been a recorded increase base water output from the now charged
aquifers, the same aquifers that supply water to the rivers’
smaller tributaries. With more discharge from the tributaries the
river runs clearer. A key importance of clearer water is that there
is more underwater light penetration, and thus an increase in the
submerged vegetation population. Underwater vegetation is key for
macro invertebrate, the forage species’ primary food source.
Underwater vegetation provides cover to the macro invertebrate, as
well as utilizing nutrients that may other wise be used by water
clouding algae.
The
river’s forage base population is dynamic and dependant on the
rivers changing system. Shorter winters produce a higher forage
specie winter survival ratio. Further more, when they do hatch at
high populations into a large population of macro invertebrate,
it’s easy to see why the shad and other forage species have been
thriving. It’s easy
to understand why shad and shiners have abundantly appeared up and
down the St. Croix and Old Man River, it’s just a cycle. After
this typical winter we are currently enjoying, many of these
surviving shad will die off. The die off should produce a more
angler minded cupboard, one that is hopefully slightly bare. With
less food on the shelf, hopefully the white tips will be more than
willing to accept a slightly different version of a wafer thin after
dinner mint. My version of a walleye pallet cleanser - a 1/8-ounce
chartreuse marabou jig tipped with a plump fathead minnow.
Keep
catchin’.
Turk Gierke
www.croixsippi.com
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