Saugeye Reproduction By Jim Corey
I posted this on Walleye Central in answer to a question and thought I'd post it here too FYI:
By Jim Corey
Contrary to popular belief, Saugeyes can and do reproduce both with either parent species and
with other Saugeyes. The most informative study that I have been able to find on the subject
was done by M.C. Hearn in 1986, titled "Reproductive viability of Walleye-Sauger hybrids". It
was published in the Progressive Fish-Culturist 48:149150.(now the North American
Part of the confusion lies in the fact that all Saugeyes are not created equal. Of the eggs
resulting from the cross of a male Sauger and a female Walleye (F1 Hybrids), some will turn
out to be true Triploid Saugeyes (sterile hybrids), while others from the same egg mass will
not develop eggs or even show recognizable gender differences. Still others will develop with
the ability to produce viable eggs. In the study done by Hearns, the eggs from Female F1
Hybrids (Saugeyes) were fertilized by milt from male Saugers. The results were 38%
"swim-up-fry". This term means that, out of the total eggs produced by this single cross, 38%
lived to complete the swim to the surface necessary for Walleye/Sauger/Saugeye fry to break
the surface tension of the waters' surface and take that mouthfull of air needed to fill their
swim bladders for the first time. They then performed the same experiment with one male and
one female F1 Hybrid (Saugeye) and, when Saugeye-to-Saugeye, the % of swim-up-fry was
46%, 8% better than when the Saugeye eggs were fertilized by milt from a parent species.
Further confusion is caused when the body of water where the Saugeyes are stocked has no
proper spawning habitat. Naturally, no reproduction can take place in such waters. In different
bodies of water the survival rate of Walleye fry to adulthood may range from 1% to 10%,
depending on predation and other factors. That figure is basically the same for stocked
Saugeye fry. With Saugeye, however, only a small percentage of the fish that reach adulthood
will be capable of producing viable eggs. Then, of course, if those eggs aren't deposited in the
proper spawning areas, under the right conditions, and fertilized with milt from that equally
small percentage of male Saugeyes who are virile, the whole point is moot.
In the right body of water, with the right conditions, Saugeye can and do reproduce, but in a
limited way, and not in a way to sustain a population without stocking.
The best source that I know of for information on Saugeye can be gotten from the Ohio State
University, Department of BioSciences.
Other studies of interest are:
"Comparative survival, growth, and reproductive development of juvenile Walleye, Sauger,
and their hybrids reared under intensive culture conditions." J.A. Malison, D.L. Johnson, and
S.A. Schell. 1982 North American Journal of Fisheries Management 2:381-387
"Reproduction of Saugeyes (Fx Hybrids) and Walleyes in Normandy Reservoir, Tennesee." F.C.
Fiss, S.M. Sammons, P.W. Betolli, and N. Billington, 1997. North American Journal of Fisheries
Here's some more Saugeye info:
When the ODNR first decided to explore the idea of stocking Saugeyes they had the OSU Bio
Sciences people do extensive experimenting in controlled environments like aquaculture
ponds,tanks, etc.. The first real effort at stocking was at Pleasant Hill in 1979. They expected
that, being hybrids, the offspring would be sterile. There were studies being done on the
Kentucky Lake stockings at about the same time but apparently the powers that be in Ohio
didn't know of them or disregarded the findings. I find it hard to believe that they weren't
aware because much of the data used by OSU was taken directly from prior studies in
Kentucky. From what I can find, the OSU people knew by 1882 that Saugeyes were capable of
limited reproduction. Their findings were given directly to the ODNR and used as guidelines by
the State hatcheries. There may have been more but I was only able to find one radio
telemetry study done on Saugeye released into Ohio reservoirs. This study claims that
Saugeye were not a risk to downstream habitats and ecosystems because they stayed up near
where they came from (reservoir) Only one of the radio tagged fish traveled any distance
downstream and it returned eventually to it's starting place. I believe that this study was too
small and incomplete and I believe that significant numbers of Saugeyes have entered the
river systems. Any time more than ten years ago an angler could expect to catch an
occasional naturally occuring crossbreed in the Ohio River. Most anglers didn't know the
difference between them and Sauger or Walleye, depending on the individual morphology of
the fish caught. Today Saugeyes can comprise the lions share of the catch on some days. I
think that the ODNR is a little nervous about admitting that the Saugeyes are breeding in any
numbers at all because that would be admitting that they didn't do enough studies and could be
considered at fault for the dilution of the Walleye gene pool in the Rivers. The scientific
evidence is there but if you ask a Game Warden they will invariablly tell you that Saugeyes are
A serious effort is on to develop a true Triploid Saugeye, one that is 100% sterile. Methods
such as subjecting the eggs or newly hatched fry to elevated water temperatures for controlled
time periods and the same with decreased water temps have been tried with moderate
success. The best that they have been able to do is by increasing the atmospheric pressure in
tanks but even this doesn't produce 100%. The following is a quote from a study titled "Use of
Erythrocyte Measurements to Identify Triploid Saugeyes" by Mary Ann R. Garcia-Abiado,
Conrad Dabrowski, James E. Christensen, and Serguisz Czesny from the School of Natural
Resources, Ohio State University and by Przemyslaw Bajer from the University of Lodz,
"The production of triploid saugeyes offers possible benefits to stocking programs and to
aquaculture. Triploidity induction will prevent fertile diploid saugeyes from contaminating
parental stocks and producing second generation hybrids. Extensive saugeye reproduction in
the Ohio River (White & Schell 1995), Normandy Reservoir, Tennessee (Fiss et al. 1997), and
in the Illinois River (Billington et al. 1997) has compromised the genetic integrity of local and
downstream parental stocks by producing second generation hybrids."........"We currently lack
a practical technique for fish managers or culturists to use in assessing the success of inducing
triploidity in saugeye juveniles for reservoir stocking or grow out."
The proof is there but for some reason the powers that be in our State Fisheries Departments
don't want to fess up. Instead they allow the angling public to believe incorrect information,
some of which originated in press releases given out by the ODNR when the stockings began,
rather than educate the public with factual up to date information.
More in a different vein:
One of the most common problems with the identification of Saugeyes, Walleyes, and Saugers
has to do with the lack of factual information provided to the angling public. Experienced
anglers can easily tell the difference between Saugers and Walleyes but when you throw
Saugeyes into the equation things can get confusing very quickly. Just as in humans, fish
inherit genetic traits from both parents. Although the majority of Saugeye from any one mating
of a female Walleye and a male Sauger will end up with the common physical characteristics of
Saugeyes that we see in pictures and articles on the subject, there are always some that will
favor "Mom" or some that will look more like "Dad".
In one of our area reservoirs, Tappan Lake, Walleye stockings were stopped after 1976 and
yearly Saugeye stocking were begun in 1990, with an experimental stocking done in 1986.
Annual stockings have averaged from 300,000 to 600,000 fingerlings per year. Anglers today
still claim to catch pure Walleyes here on occasion, although the odds against it are staggering.
Walleye lifespans at this latitude average from 8 to 12 years, with old fish occasionally
reaching 15 years of age. ( These figures are for our inland lakes and may be different for
Erie) Even if there were an old female swimming around, genetically uncorrupted, the odds of
her eggs being fertilized by another existing pure male Walleye are even more staggering,
especially since Walleye spawning habits are not monogamous and several males may fertilize
the eggs of any one female. If local anglers see no well defined saddle markings on the fish,
they believe that it is a pure Walleye.
In any waters where Walleye and Sauger coexist and have overlapping spawning habitat there
will be a naturally ocurring population of Hybrids (Saugeyes). Most estimates for waters like
the Ohio and Missouri River systems run about 4% of the total combined species. This 4%
poses no threat to the gene pool of either parent species and can be reabsorbed. When the
number of Saugeyes is increased dramatically by upstream stocking programs it becomes
impossible to prevent eventual contamination of the parental species.
The following is a quote from a study titled "Evaluation of Skin Pigmentation for Identifying
Adult Saugers and Walleye-Sauger F1 Hybrids Collected from Lake Sakakawea, North Dakota."
"Correct identification of brood fish from waters where sympatric species hybdidize presents a
challenge to fisheries managers and hatchery biologists. Misidentification of brood stock can
result in inadvertent hybridization and the failure of hatchery programs."
We are seeing the results of such incorrect identification here in Ohio. Traditional inland
Walleye lakes like Seneca and Salt Fork are now being stocked with Saugeyes. When
questioned about the reasons for this, the ODNR blames anglers for releasing Saugeyes into
the lakes and corrupting the existing Walleye populations. Salt Fork Lake had long been a
"Mother Lake", one where hatcheries personell collected female Walleyes to strip eggs for the
State hatcheries programs. One of the States largest hatcheries in just below the dam on
Seneca lake. Some of the fry and fingerlings from the eggs harvested made their way back
into these lakes through stocking programs. The Female Walleyes were identified by
morphology (physical characteristics) by the hatcheries personell at the time of capture. Here
is another quote from the same study quoted above. It is based on the capture of 143 fish
from Lake Sakakawea, 14 of which (10%) turned out, under genetic testing, to be incorrectly
identified as Sauger by using physical characteristics.
"In the context of fish culture operations, the consequenses of a 10% error rate can be
enormous. We used Hearns (1986) data to show how the genetic composition of the Sauger
population of Lake Sakakawea could have been changed if the incorrectly identified fish were
used as broodfish. Hearn (1986) crossed two F1 hybrid (Saugeyes) females with Sauger males
and produced about 47,000 fingerlings. Of the 14 fish we identified as F1 hybrids eight were
females, two were males, and the gender of four could not be determined. Given success
comparable to Hearns(1986) about 188,000 fingerlings could be produced from the eight
females. Hearn used one male to fertilize three females. Following this protocol, if the male
hybrids were used as brood fish, a total of about 580,000 hybrid fingerlings could result."
It seems far more likely that the presence of Saugeyes in lakes like Salt Fork and Seneca
stem from misidentification of brood stock and subsequent stocking of hybrids rather than by
fish released by a few anglers.