DALE HOLLOW AND CENTER HILL WALLEYE by Vernon Summerlin
Walleye and its cousin, sauger, have been on the decline for a number of
years. What has happened and what is being done to assure us of future
fishing for members of the perch family?
Most of the pressure on walleye comes during their spawning runs when they
are easier to catch. Today there is a move among Tennessee's anglers toward
year-round sport fishing for them. They are being furnished by Tennessee
Wildlife Resources Agency for stocking to take care of the growing demand.
As you will read later, there are two varieties of walleye that fill niches
created by the damming of the Obey and Caney Fork Rivers.
WALLEYE OF YESTERDAY
Walleye have survived and thrived for 10,000 years but after dams were
constructed on Tennessee rivers their numbers plummeted. The loss of
habitat and spawning areas have declined to the point stocking is required,
but the stocked walleye do very well in Tennessee lakes because of the
forage base.
Since the building of dams on the Tennessee River, sediment has covered
the gravel spawning grounds. This loss of spawning habitat caused poor to
non-existent recruitment and eventual decline in walleye populations. Water
level fluctuations disrupt the life cycle of walleye also. There is better
recruitment during the years we have high water.
Because of the lost of habitat and mixed gene pool, it is not likely that
we will ever see the likes of the walleye caught by Mabry Harper from Old
Hickory in 1960. His fish weighed 25 pounds.
Let's learn why the gene pool of the great Southern walleye has become
polluted from TWRA fisheries biologist Anders Myhr.
WALLEYE IN DALE HOLLOW AND CENTER HILL LAKES
Myhr heads the Region III office and addresses the changes in the walleye
population in Dale Hollow since the early 1980s.
"TWRA started a tagging project in 1984," Myhr says, "to see where the
tagged fish were eventually caught and how far they traveled from where
they were released. We learned that four straight years of recruitment were
missed. That means there were no significant numbers of survivors of the
spawns for four years. All the fish were four to 20 years old. Some walleye
in Dale Hollow are 25 years olds."
Myhr was puzzled by this four-year gap in recruitment and asked why?
"In looking back four years to see what had changed in the lake," says
Myhr, "I came to suspect the introduction of the alewife. Threadfin shad
die off every year due to the cold weather and it was the forage base for
the fish. In 1979 we stocked alewife because it is winter hardy. More
research has shown that other lakes that stocked the alewife started
showing loss of recruitment of some species.
"The second thing we learned from the tagging study was that there are two
distinct spawning walleye populations in Dale Hollow. Before the river was
impounded, there was a natural population of walleye but after the
impounding, coal mining upstream hurt those fish. To repopulate the lake,
some walleye from New York were brought in, as well as from other states.
These new fish stayed in the lower half of the lake and the indigenous fish
stayed in the upper portion of the lake. Even in the summer time, these two
populations don't over lap much.
"We were stocking every other year," says Myhr. "We go in and net them the
year we don't stock to see if they are surviving. They are, but we still
don't see any natural reproduction. We began stocking every years when the
Normandy Hatchery came on line. TWRA is trying to maintain both populations
of walleye.
"The alewife has done a wonderful job of providing a stable forage base.
The lack of natural reproduction of the walleye was the one drawback but we
can live with it. It may have impacted the white bass too but other lakes
are having trouble with white bass reproduction now. I can't say for sure
that it's competition with the alewife that is causing the decline in their
numbers. The white bass spawns right after the walleye and their young may
be in competition with the alewife too.
TWO WALLEYE NICHES
"We have tried to identify the two walleye populations genetically but we
have not been able to. What I think has happened is that over the years we
have put so many different strains of walleye in Dale Hollow that we have
complicated the fish beyond recovery."
Since 1964, Myhr has noticed the fish in the upper population of Dale
Hollow's walleye are twice the size of the lower lake walleye. That goes
back to the theory that the southern strain of walleye was larger. The
world record 25-pound walleye that came from Old Hickory Lake is believed
to have been a southern walleye. Arkansas has some of that strain and TWRA
imports some of them.
"I'm convinced," says Myhr, "that we have two separate strains in Dale
Hollow even if it doesn't show up genetically. There may not be a pure
genetic separation, but I still believe the upper lake walleyes are natural
to the waters."
The bass population has increased dramatically over the last 15 years that
the alewives have been in the lake he adds. The alewife fits a specific
niche. They only come to the surface to spawn in late April and early May.
Alewives stay at the thermocline and will be 40 feet deep all summer. The
walleye utilizes the alewife because they are oriented to that depth in the
summer. The rainbow trout and lake trout orient below the thermocline and
they work on the alewife too. The smallmouth also utilizes them. Spotted
and largemouth bass utilize the threadfin shad more.
Myhr collects brood fish from both walleye populations in Dale Hollow for
reproduction. He takes the fish to the hatchery where they are stimulated
to spawn, the eggs are fertilized, hatched and placed in rearing ponds for
no more than 30 days because of cannibalism. The ponds are drained and the
small walleye are taken for stocking.
Center Hill is dependent on the spawning in the Blue Hole area of the lake
and Myhr says it is the only known spawning area. "During the years of low
water flow the fry die and that is fairly often on Center Hill. We are
trying to establish a mid-lake spawning population here like we have in
Dale Hollow. We have documented that some of our stockings have worked.
We've found some spawning close to the dam. I feel we are successful at
establishing two spawning populations in Center Hill. The mid-lake spawners
provide a stop gap in case we have a complete failure in the Blue Hole
region."
Myhr admits, "We have learned a lot from this experience with walleye. We
should have stuck with stocking fingerlings from our own populations rather
than bringing in walleye from all over. We really messed up the genetics
but at the time we didn't know any better. We biologists make mistakes like
everyone else. Now we're trying to make the best of it."
After Center Hill was impounded, there were a lot of big walleye caught
and TWRA began stocking the lake. It has had more stockings and fish from
more places than Dale Hollow has. "This cost Center Hill the size
advantage. Now the average size walleye in that lake is about half the size
of those in Dale Hollow", says Myhr, "and you can expect to catch a
five-pounder in Dale Hollow."
TWRA has no crystal ball that predicts the future but they have a body of
scientific data to suggest their next steps. The Normandy Hatchery is an
example of seeing a need in the future being prepared. That hatchery
provides anglers with walleye and sauger, and several other species.