With
Lake Erie’s top-end predator population having filled nearly all of
its nooks and crannies the status of the supporting forage has never
become more vital.
And
the verdict from Ohio Division of Wildlife is “good.” Well,
probably good, anyway, with some signs of stretch marks. These
indicators appeared following the several recent arrivals of abundant
hatches of walleye. So much so the lakewide population of walleye is
pegged at 41 million fish, more than anywhere else on earth.
And
in some places, particularly in the lake’s Western Basin, pretty
respectable numbers of yellow perch exist as well.
Yet
savvy anglers are beginning to notice some peculiarities, especially
when it comes time to fillet the walleye they catch. Often the
dissected walleye are being seen to have little in their stomachs
though the pre-gutted fish do appear healthy overall.
Also,
another key anecdotal point is while some walleye fishers report
seeing images on their electronic fish finders of clouds of bait,
these electronic snapshots suggest a greater than usual randomness to
their frequency.
Among
the puzzled anglers is Huntsburg Township (Geauga County) licensed
charter captain Marv DeGreen. DeGreen operates his “Evil Eye”
charters out of the Grand River.
On
one recent outing DeGreen said he hadn’t viewed on his fish
finder’s video screen much in the way of what one could call
“clouds” of bait. However, the next day while trolling in 70 feet
of water, DeGreen said his fish finder showed massively large images
of rainbow smelt. His assurances that these underwater thunderheads
were made up of smelt were bolstered by the walleye and steelhead his
customers reeled in.
“The
fish were regurgitating smelt when we brought them in with the net,
and the cooler had a lot of smelt the fish had tossed up,” DeGreen
said. “No question, the walleye are hungry and are looking for
forage to eat.”
Mentor
angler Bob Ashley has visualized similar incidences of this
here-and-there forage partially cloudy conditions while angling off
the Mentor Lagoons.
When
asked what he’s been finding in the stomachs of the walleye that he
and his friends have taken and then cleaned, Ashley’s answer was
blunt and to the point: “Nothing.”
Even
so, a lot of agency optimism exists regarding the overall health of
Lake Erie’s forage base along with its varied top-end predator
populations, says Wildlife Division fisheries biologists Travis
Hartman and Tim Bader.
Hartman
is in charge of the Wildlife Division’s Lake Erie fisheries section
and works out of the agency’s Sandusky office. Meanwhile, Bader is
a fisheries scientist who toils over trawling, gill netting and other
data collected on behalf of the agency’s Fairport Harbor Fisheries
Research Station.
“The
really good news is that Lake Erie is by far the most productive of
all the five Great Lakes,” Hartman said. “It has the most
abundance and the most diversity when it comes to forage.”
Such
diversity runs from native species to exotic interlopers – which
increasingly have become vital in Lake Erie’s predator-prey
relationship. Among the natives are emerald and spot-tail shiners,
mayflies as well as so-called midges.
Among
the exotics are such species as gizzard shad, rainbow smelt, spiny
water “fleas,” white perch, and gobies. Several of these species
have occupied Lake Erie’s floor space for so long that for all
practical purposes they are now biologically stamped with the “Made
In America” label. Yet they remain what they are: Invasives that
have succeeded as immigrants.
“Smelt
populations are down overall but we are seeing good populations of
gizzard shad, and we’re also seeing improvement in our emerald
shiner populations,” Hartman said, continuing.
Down
as well are round gobies with the 2019 international Lake Erie Forage
Task Force report citing this species population – in the lake’s
Western Basin at least - as being “… the lowest since the fish
was first detected in the west basin (1997).”
And
the joint U.S.-Canadian Forage Task Force report also says for Lake
Erie’s Central Basin that “Forage abundance in Ohio waters has
generally decreased since 2012. In 2018, most forage species
continued to decline and are at the lowest densities since 1993.”
Even
so, Hartman acknowledges how forage abundance and large doses of
predators has coincided before. Such a coalescence came about during
the 1980s; often referred to as the “good old days” of Lake Erie
walleye angling. Or at least they were before this current hot streak
of walleye fishing.
Hartman
does say too that a walleye will not shy away from eating anything
that comes across its path, among the menu items being small yellow
perch, and even their own progeny.
“We
do see small yellow perch show up in the stomach contents of the
walleye we sample but it’s less than 20 percent,” Hartman said.
Walleye
that have – for whatever reason - gathered off the mouths of the
six rivers the Ohio Division of Wildlife stocks annually with 450,000
steelhead are not above eating these soft-rayed smolts, either, added
Hartman.
“But
we don’t have much actual data on that,” Hartman admitted.
Still,
information collection of all kinds is vital. Such work includes
checking the stomach contents of the fish the Wildlife Division
encounters during its annual Central Basin summer-time trawls and
seasonal gill net operations. All are important metrics in judging
the health of both Lake Erie’s predator and prey populations, says
Bader.
For
that work the Fairport Fisheries Research Station continues to employ
its 29-year-old fisheries research vessel, the “Grandon.”
“In
the summer we see a mixed bag of prey the walleye feed on: white
perch, shiners and smelt,” Bader said. “In the fall we see a
switch to predominately young gizzard shad, fish that are six to
eight inches long: something that can easily fit inside a walleye’s
mouth.”
In
regards to the importance of invertebrates, both Hartman and Bader
said these creatures are essential prey for both walleye and yellow
perch.
In
the lake’s Western Basin this invertebrate biomass largely consists
of mayfly larvae that pupate and ascend through the water column
toward the surface. There the mayflies emerge as mating adults. In
the lake’s Central Basin, the chief invertebrate are the infamous –
and native - “midges,” or “muffleheads.” Scientifically,
these non-biting fellows are labeled Chironomous plumosus.
“The
midges are more important to a yellow perch’s diet than they are a
walleye’s diet, though the mayfly in the Western Basin is important
to that latter species.” Bader said.
So
while Lake Erie has a current huge diversity and abundance of
available prey, the notion the 9,910 square mile body of water has
reached the predator-base saturation point is unlikely, though not
entirely out of the equation.
“That’s
a good question,” Hartman said, mulling over the idea. “I don’t
have a definitive answer since fish production is such a variable,
but I will say Lake Erie has excellent productivity for both prey and
predators.”
For
now, at least, that observation will have to suffice.
JFrischk@Ameritech.net
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