Wednesday, February 1st, 2023
Wednesday, February 1st, 2023

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Sportsmen Since 1967

Stocking ‘eyes in Erie nearly impossible

With the announcement by the DNR Division of Wildlife of yet
another dismal hatch and/or survival of young-of-year walleyes in
Lake Erie, some charter boat captains and other concerned fishermen
are once again wondering if the time is right to supplement the
walleye population by stocking additional offspring into the
lake.

After all, walleyes are stocked each spring from eggs collected
by Division of Wildlife into a number of inland reservoirs such as
Lake Milton, LaDue Reservoir and C. J. Brown to name a few. Many
are now questioning why the same can’t be done for Lake Erie.

For one thing, the size of Ohio’s portion of Lake Erie is a huge
2.24 million surface acres, compared to the smaller bodies of water
mentioned above, which respectively are 1,684, 1,475 and 2,022
acres.

According to Division of Wildlife Fish Hatchery Administrator
Elmer Heyob, there currently are 137 acres of walleye-rearing pond
available in the Hebron State Fish Hatchery dedicated to walleye
production.

The hatcheries now keep the various fish species that they raise
separate to reduce the chance of spreading diseases such as viral
hemorrhagic septicemia (VHS) onto multiple facilities from the wild
fish and/or eggs used as brood stock.

According to Roger Knight, Lake Erie Fisheries Supervisor for
Division of Wildlife, the walleye task group considers that an
“average” year class in Lake Erie will add 10 million age 2
walleyes to the fishery. This would take 224 million fingerling
walleyes, if they have a 4.5 percent survival rate to age 2.

Doing some simple math, it would therefore take 4,384 acres of
ponds, which is 32 times more manpower, equipment and pond space
each year than is currently available.

Instead of the 2,275 female walleyes handled this past year to
obtain the eggs necessary to stock the inland lakes, hatchery
personnel would have to handle 72,800 female walleyes to gather
some 896 million eggs, as only about 50 percent hatch, then 50
percent of them make it to fingerling size.

Secondly, the walleyes in the inland lakes that currently
receive stocking of this species do not reproduce naturally due to
lack of suitable spawning habitat, homing instincts, or excessive
predation to be able to sustain a fishable population without
help.

Thirdly, it is deemed to be very important to Ohio’s fisheries
biologists that the genetic variability and integrity of all of the
various Lake Erie spawning stocks of walleyes be maintained.
Collecting all of the brood stock from one location, although the
most convenient, would be discouraged.

Instead, it would be necessary to mimic the natural spawning
contributions by taking fish from several of the known spawning
sites such as the Maumee River and Bay, Sandusky River and Bay, and
the various reefs and shoals that currently support
sub-populations.

Walleyes that are stocked are generally raised to the young
fingerling stage, because as soon as they switch from zooplankton
to fish diets, at about an inch and a half long, they become
aggressively cannibalistic and cannot be confined in ponds at high
densities any longer.

More numbers could be released if they were released as fry. But
dumping a lot of fry into Lake Erie would likely to make a lot of
gobies, rock bass and white perch fat and happy, and they would
still have to overcome the same environmental conditions that the
wild fry face. Plus, fry need to be stocked at 10 times the numbers
to get the same survival rates as the fingerings. If all fry were
used, the number of females that would need to be stripped of her
eggs adds up to 720,000 to get 22,400,000,000 eggs.

Finally, even if all of the effort was placed into a stocking of
this magnitude, there’s no guarantee that these fish will even live
long enough to add to the population. Muddy water and water
temperature reversals account for many early larval fish
mortalities, which would affect naturally spawned or stocked fish
equally.

Successful recruitment into the fishery only occurs in years
when the fish get through the hurdles of larval development and
reach a size large enough to survive through their first
winter.

With zebra and quagga mussels now commandeering much of the
primary food chain production (green algae), it is unlikely that
the lake will ever support fish in the numbers found prior to the
mussel infestation.

These algae support various shapes and sizes of zooplankton such
as rotifers, water fleas and copepods that are necessary for the
walleye fry to feed upon until they reach fingerling size and can
add smaller fish fry to their diet. A 90 percent reduction of some
of these zooplankton groups has occurred during some years of low
productivity.

In years when the lake’s stressed food chain cannot support even
all of the naturally produced walleye larvae, additional stocked
fish would also die due to density dependent factors such as
malnutrition, disease and predation.

So, with some natural spawning success still occurring each
spring, and the occasional bigger hatch still occurring when
conditions allow, the time to start stocking Lake Erie with
additional walleyes isn’t here yet, according to the experts.

In the years when the weather cooperates and the lake is prime
to support good larval fish survival, as in 2003, natural
reproduction dwarfs any feasible stocking scenario.

Knight speculates that if the time comes when Lake Erie walleyes
stop reproducing altogether, Ohio would join the other
jurisdictions to collaboratively re-stock the lake, not take on the
duty alone.

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