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Michigan Department of Natural Resources Branch County (T5S, R7 and 8W, Sections 6, 7, 11, 12, 14) Surveyed June 11 and 12, 1991 Gary L. Towns In the early 1920s the cost of electricity produced by the burning of
coal was thought to be prohibitively expensive in the community of Union
City, Branch County. As the town grew in size and electrical demands increased,
a hydroelectrical plant was suggested as a means to deliver cheaper electricity
to the town. By 1923 Riley Dam was constructed on nearby St. Joseph River,
and the backwater that formed behind the dam was known as Municipal Pond.
This water body was later named Union Lake. Union Lake lies in northwestern Branch County. The closest community
is Union City which is less than a mile from the lake's northeastern shore.
Coldwater is the closest large city (14 miles to the southeast). When
traveling downstream, Union Lake is the first large reservoir (525 acres)
on the St. Joseph River. The river and its tributaries above the dam drain
approximately 534 square miles. The average discharge over the dam is
470 cubic feet per second (Richard Popp, Michigan Department of Natural
Resources, personal communication, 1991). This is a shallow lake with a maximum depth of only 16 feet (see
map of Union Lake). Most of the lake is between 5 and 10 feet in depth.
Approximately 1/4 of the lake (on the northeast end, near the inlet) is
very shallow (less than 3 feet) and marshy with islands of cattails and
other emergent aquatic plants. The lake is long (2.5 miles) and narrow
(1/3 mile), typical of impoundments in this area. Basin substrates are
composed almost entirely of sand and organic material. Some gravel is
evident in a few shallow areas. Submerged tree stumps are scattered throughout
the basin but are most heavily concentrated in the shallow northeast end. The land near the shores of Union Lake is gently rolling (0 to 6% slopes)
and composed mostly of sandy loam soils. However, there are some steep
slopes to the waters edge along the immediate shoreline. Most of the shore
area is developed with cottages and permanent homes, but landward from
this development the land is heavily farmed. A state-owned access site
with concrete boat launch allows year-around public access. This site
is located on the northern shore. There is a great deal of information in the Fisheries Division files
regarding the history of Union Lake. This lake has been fortunate to have
had considerable citizen interest and active involvement in the development
of the fishery over the past 70 years. Fish stocking began soon after the reservoir was formed. Records indicate
yellow perch, bluegill, largemouth bass, smallmouth bass, and walleye
were stocked at various times from 1922 through the mid-1940s. The most
frequently stocked of these species were bluegills and largemouth bass.
Later, research showed that, in most cases, stocking panfish species into
already established populations is inefficient and uneconomical. The fish
population in Union Lake was probably well established within 6 to 8 years
of it's creation. It is apparent that for some time Union Lake, to which "anglers came
from many states", was considered as one of the best fishing lakes in
Southern Michigan. Typically, in a newly created water body, competition
for food is minimal and fish grow very fast and attain unusually large
sizes. The lake was fished so heavily, and so many fish were harvested,
that the local citizens soon felt there was a need for restocking. The
local Chamber of Commerce contacted the (then) Michigan Department of
Conservation, and soon "tank wagons with fingerlings" were sent to Union
Lake. These fingerlings were probably some of those referred to in the
previous paragraph. As time went on, the local perception was that even with the state plantings
harvest was exceeding recruitment. In response, bluegill and bass rearing
ponds were created and used to stock the lake for several years. Fishing
was then said to be "unmatched at any place in Michigan". In the late 1940's another perception was conceived: an over-population
of fish. Fish plantings were discontinued and the rearing ponds fell into
disrepair. Complaints of poor bluegill fishing began in the 1950's, but for quite
some time others claimed fishing was very good. By the early 1960's, however,
so many people had been convinced of a declining fishery that a fish ladder
over the dam was proposed. Alternatively, it was proposed to net and lift
fish over the dam. The solution finally agreed upon was the reactivation
of the bluegill rearing ponds near the dam. These ponds were sponsored
by the Union City Betterment Association and the Union Lake Fisherman's
League. Anglers were asked to donate part of their catch of bluegills
and sunfish to the pond for broodstock. Apparently, the exact numbers
of donated broodstock were not known. Even so, this system worked surprisingly
well, and the first year of production yielded an estimated 500,000 fingerlings.
This method of rearing and stocking bluegills was used throughout the
1960's with much enthusiasm and cooperation from area citizens. The first data on the fishery appear as angler creel census interviews
collected during mid- 1940's and 1950's. These data indicated that fishing
in Union Lake was good for bluegill, largemouth bass, pumpkinseed, black
crappie, yellow perch, and northern pike. The first intensive fishery survey on record occurred in 1960. A large
seine was used, but "many snags made it impossible to bring in a large
haul." Not many fish were captured; however, all game fish species were
found to be growing well above state average growth rates. A better catch of fish was made in 1962 with trap and fyke nets. A large
variety of fish were captured including bluegill, pumpkinseed, black crappie,
largemouth bass, warmouth, northern pike, yellow perch, bullhead, redhorse,
white sucker, bowfin (dogfish), and carp. By weight, this catch was predominately
redhorse, white sucker, and carp. Yet, there were large numbers of good-sized
game fish present. Bluegills averaged 6.9 inches, crappies 7.9 inches,
largemouth bass 13.7 inches, and northern pike 27.5 inches in length. In 1967, the Union Lake Fisherman's League stocked 7500 channel catfish
averaging 6 inches long. Some of these apparently survived, since four
catfish were captured during a gill net survey in 1971. In that survey
a great variety of fish species were captured, including smallmouth bass
(1), common shiner, and golden shiner-in addition to those species mentioned
above. A 1972 fyke net and boom shocker survey captured few fish and was rather
inconclusive. However, some fish species were captured which were formerly
not recorded at Union Lake, including: green sunfish, log perch, and brook
silverside. An extensive week-long, trap net survey was carried out in June of 1983.
Twelve net-nights of trap net effort resulted in a good sample of fish.
All game fish species (with the exception of young black crappie) were
found to be growing at rates exceeding state averages. This was especially
true of bluegill and largemouth bass. However, these two species were
in rather short supply. The number of fish caught per net per night (CPE)
was rather low when compared to many other lakes in the area. For example
bluegill CPE was 18.7. Bluegills averaged 7.1 inches, and 87% were 6 inches
or longer. Several large channel catfish were captured and appeared to
be in good condition. Carp, redhorse, and suckers made up 44% of the catch
by weight. Fisheries Division surveyed the fish population again in 1987. Trap nets
and experimental gill nets were used in the collection of over 1000 fish.
The survey indicated that Union Lake supported a fine gamefish fishery.
However, it was obvious that the fish population in Union Lake was greatly
influenced by the St. Joseph River. Nearly 48% of the trap net catch (by
weight) was composed of rough fish (primarily carp, redhorse, and white
sucker). These same species accounted for the vast majority of the standing
crop in the St. Joseph River in l987 (Towns 1988). Since the early 1980's the Union Lake Association has sponsored a "Carp
Rodeo". This consists of a weekend carnival where teams of contestants
catch, spear, or shoot (bow-and-arrow) as many carp as possible. Prizes
are generally awarded to the team with the most carp. A few years ago,
as many as 2000 carp were removed from the lake during this event. More
recently, however, effort has been reduced resulting in the annual removal
of approximately 300 adult carp. The average size of the bluegills captured by trap nets in 1987 was excellent
when compared to other lakes in southern Michigan. The 66 bluegills captured
averaged 7.2 inches and nearly 1/3 pound. The 485 crappies taken with
trap nets averaged an impressive 9.2 inches. Largemouth bass were also
found to be doing well. Twenty were caught, ranging in length from 4.7
to 19.3 inches; six of these were 14.9 inches or larger. Rapid growth
was indicated by scale analysis (1.4 inches above state average growth
rates). Although of rather small average size (7.0 inches), a fair catch
of yellow perch was made in 1987. Walleye fry were stocked in Union Lake in 1984, and a few fingerlings
were stocked by the lake association in l986. In l987, Fisheries Division
stocked 30,000 small (1.4 inch) and 18,700 larger (2.8 inch) walleye fingerlings.
Three of these were captured during the 1987 survey. Scale analysis indicated
very rapid growth. During a subsequent electrofishing survey on October
28, l987, five walleyes were captured, ranging in length from 9 to 16
inches. Results of the 1987 survey indicated that channel catfish were doing
well in Union Lake. Twenty-one were captured ranging in size from 9 to
24 inches. Good populations of channel cats had recently been found in
the St. Joseph River below the lake (Towns 1988). Individual game fish growth rates observed in 1987 were again impressive.
Bluegills, for example, were found to be growing 2.4 inches above state
average rates. However, once again, relatively few bluegills were captured
(total = 66; CPE = 8.3). In 1990, we stocked 35,100 bluegill fingerlings (averaging 2.2 inches)
in Union Lake. These fingerlings were surplus stock made available through
the termination of a fisheries research project at the Saline Fisheries
Station. In the late 1970's, the rearing pond was once again put into use, but
this time for rearing northern pike. Since that time, the pond has been
used for rearing pike, walleye, and redear sunfish fingerlings. In more
recent years, a double-harvest system has been employed. Northern pike
fry are stocked in the early spring and fingerlings are harvested in early
summer. The pond is then refilled, and a second species is stocked and
reared through the balance of the summer and early fall. In 1988, a Fisheries
Division program (Inland Fisheries Cooperative Grants Program) provided
a grant to deepen the pond via dredging. Approximately 7000 cubic yards
of sediment were removed from this 4-acre pond. Union Lake was the subject of much controversy during the early 1980's
because of the mysterious disappearance of profuse growths of aquatic
plants. Complaints of "huge vegetation beds" date as far back as 1954.
Apparently, the aquatic vegetation had been becoming more and more abundant
to that point. But in the mid 1970's, the files contain references to
disappearing weeds. In 1982 and 1983, observations by DNR Water Quality Division staff indicated
the absence of rooted, aquatic vegetation in Union Lake. A great deal
of testing found no obvious chemical cause for this phenomenon. It was
suggested that the most probable cause was excessive turbidity, resulting
from resuspension of sediments by carp and redhorse suckers, and the dense
phytoplankton algal growths that grew in response to the nutrient rich
conditions (Wuycheck 1984). The feeding habits of these fish cause turbidity
to increase as they scour and sift the bottom sediments for food. The
resulting turbidity shaded out rooted vegetation. In addition, carp are
known to uproot and consume plant materials during their feeding activities. As with surveys in the past, the 1991 catch results indicated that the
fish population in Union Lake is greatly influenced by the St. Joseph
River (Table 1). Over 32% of the trap net catch and 67% of the gill net
catch (by weight) were composed of rough fish (primarily carp, redhorse,
and white sucker). These same species accounted for the vast majority
of the standing crop in the St. Joseph River in l987 (Towns 1988). Yet,
the present survey also indicated that Union Lake supported a fine game
fish fishery. The average size of the bluegills captured in 1991 was excellent when
compared to other lakes in southern Michigan. The 118 bluegills captured
in trap nets averaged 7.7 inches in length and nearly 1/3 pound in weight.
By comparison an average length greater than 6.2 inches is considered
good. Bluegill growth, determined by analysis of fish scales, was also
exceptional (Table 2). These fish were growing 0.8 inches above the state
average rate. However, the number of bluegills captured was low, only
14.8 per trap net. Population characteristics of the bluegill in Union Lake have changed
little over the last decade. In 1983, their average length was 7.1 inches,
growth was 0.7 inches above the state average, and CPE was higher (18.7)-but
still low compared to other area lakes. In 1987, the bluegills averaged
7.2 inches long, growth was 2.4 inches above the state average, and CPE
was only 8.3. In recent years anglers have reported that bluegills are
very low in number. Yet, the bluegill fishery during the winter of 1990-91
was said to be exceptional with limit catches reported. Bluegills are targeted for sampling in inland lakes because of their
role in determining fish community structure and overall sportfishing
quality (Schneider 1981). Recently, a ranking system has been developed
that allows fish managers to get an idea of the relative quality of a
lake's fish population (Schneider 1990). On a scale of 1 to 7 (with 7
the highest rank) the quality of the bluegill population in Union Lake
was calculated as 6.8, "superior". The 1991 survey indicated that the black crappie population continues
to be one of the best in the six-county area of Fisheries District 13.
This species is known to thrive in turbid reservoirs. The 108 crappie
caught in trap nets averaged a very impressive 9.9 inches in length. Crappie
growth rate was slightly above the state average rate. This population
appears to be unstable because there was a large year-class of age V fish
(Table 3); however, the average length in 1987 was nearly the same, 9.2
inches. Only four largemouth bass were captured during this survey. These ranged
in length from 10 to more than 17 inches. Bass tend to avoid capture by
trap nets and this low catch should not be considered a reliable estimate
of bass abundance. In 1987, 20 bass were caught with total lengths from
4.7 to 19.3 inches. Six of those were 14.9 inches or larger. Rapid growth
was indicated by scale analysis (1.4 inches above the state average growth
rate). Channel catfish continue to flourish in Union Lake. In 1991, trap nets
captured 53 catfish which were from 4 to over 18 inches long. This population
may be expanding. Anglers have begun to report multiple catches of catfish;
one pair of anglers harvested 14 channel catfish in 2 days of fishing.
Twenty-one catfish were captured in the 1987 survey. Apparently, these fish were reproducing successfully in Union Lake since
we know of no public or private stocking effort prior to that date (except
for 1967). Since 1987 Fisheries Division has been stocking from 3,300
to 12,000 channel catfish fingerlings annually into Union Lake. However,
these fingerlings have averaged only 3.5 inches at the time of stocking.
Recent studies have indicated that the survival of channel catfish stocked
into lakes with established largemouth bass populations can be maximized
by stocking fingerlings at least as large as 7.9 inches (Storch and Newman
1988). Historically, bluegill growth rates have been considerably above the
state average, while bluegill CPE has been far below average when compared
to other lakes in the area. Also, in the late 1980's anglers reported
that bluegills seemed to be very low in number. These same observations
in the 1960's prompted local sportsman to raise bluegills and stock them
into Union Lake. Being a large reservoir, Union Lake is rather unique
in this area of the state. However, similar bluegill numbers and growth
rates have been observed in Ford Lake, another large reservoir, in Washtenaw
County (Towns 1988). In many waters bluegills tend to overpopulate due to highly efficient
reproduction. For Union Lake, however, survey data indicate that bluegill
recruitment to acceptable angling size (6 inches) is less than desirable.
With the large river entering this system, it is possible that sedimentation,
rapid water temperature changes, or fluctuating water levels during bluegill
spawning periodically cause poor spawning success. Undoubtedly, bluegills
are continually lost over the dam and cannot migrate upstream into the
lake. In addition, the high incidence of bottom-feeding rough fish may
have a detrimental impact on bluegill nesting success. Because of the unusual composition of the Union Lake fish community,
and the low population and recruitment of bluegills, this lake should
be considered for additional bluegill stocking. The ideal stocking rate
would sustain the maximum number of catchable bluegills while maintaining
bluegill growth at, or slightly above, the state average rate. However,
the fishery should be closely monitored. If bluegill natural recruitment
improves substantially, any bluegill stocking efforts should be immediately
re-evaluated. Perhaps the lake association could raise bluegills in their
rearing pond. A more costly and less desirable option would be to trap-and-transfer
bluegills from other waters where overpopulation of this species is a
problem. The channel catfish population is apparently increasing and doing very
well; stocking should continue. However, if the size of stocked fingerlings
were increased to 8 inches, survival would increase and the number stocked
could be decreased. The walleye fishery in the St. Joseph River below the lake is developing
quite well. However, very few walleye catches within the lentic environment
of Union Lake have been reported. Lake surveys have also produced very
few walleyes (none in 1991). It is possible that many small walleye fingerlings
migrate downstream (over the dam) soon after stocking. Our experience
with walleye fry and small fingerlings in other Michigan flow-through
ponds and reservoirs has been that significant numbers move downstream
soon after stocking. Further Union Lake walleye stocking efforts should
include the largest possible fingerlings (6 inch+) in hopes of preventing
walleye migration out of the system. Despite several years of northern pike stocking, recent surveys have
produced few pike. Only five were captured in 1991. To thoroughly evaluate
the pike population, however, surveys should be done in early spring during
the pike spawning run. Union Lake is maintaining a good game fish fishery despite the large
population of rough fish. A large-scale fishery manipulation, such as
a treatment with a piscicide, is not advised at this time. To have a significant
measure of success, such a treatment would have to include much of the
St. Joseph River and its tributaries within the Union Lake watershed.
It would be nearly impossible to exclude carp, redhorse, and white suckers
from this system for an extended period of time after such a treatment. Schneider, J.C. 1981. Fish communities in warmwater lakes. Michigan Department
of Natural Resources, Fisheries Research Report 1890, Ann Arbor. Schneider, J.C. 1990. Classifying bluegill populations from lake survey
data. Michigan Department of Natural Resources, Fisheries Technical Report
90-10, Ann Arbor. Storch, T. W. and D. L. Newman 1988. Effects of size of stocking on survival
and harvest of channel catfish, North American Journal of Fisheries Management
8:98-101. Towns, G.L. 1988. Analysis of the Ford Lake Fishery - Fish Collection
Report, Fisheries Division, Michigan Department of Natural Resources,
Jackson. Towns, G.L. 1988. A fisheries survey of the Upper St. Joseph River, July
and August 1987. Michigan Department of Natural Resources, Fisheries Technical
Report 88-12, Ann Arbor. Wuycheck J. 1984. A Biological and Chemical Survey of Craig Lake, Coldwater
River, St. Joseph River and Union Lake, Branch County, Michigan, August
5, 1982 through June 9, 1983. Michigan Department of Natural Resources,
Surface Water Quality Division, Staff Report, Lansing. Report Completed: January, 1992. Table 1.-Number, weight, and length indices of fish collected
from Union Lake with trap nets, June 11 and 12, 1991.
1Note some fish were measured to 0.1 inch, others to inch
group: e.g., "5" = 5.0 to 5.9 inches; "12" = 12.0 to 12.9 inches; etc. Table 2.-Average total length (inches) at age, and growth relative
to the state average, for three species of fish sampled from Union Lake
with trap and gill nets, June 11 and 12, 1991. Number of fish aged is
given in parentheses.
1Mean growth index is the average deviation from the state
average length at age. Table 3.-Estimated age frequency (percent) of two species of fish
caught from Union Lake with trap and gill nets, June 11 and 12, 1991.
Last Update: 08/06/02
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