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Michigan Department of Natural Resources Oakland County (T3N, R8 & 9E, Sections 11-14, 18) Surveyed June and July 1992 Michael V. Thomas Environment Pontiac Lake is a man-made impoundment created in 1926 when Lime Lake,
a small lake in the upper Huron River watershed, was dammed. It lies about
7 miles west of Pontiac, Michigan. A mosaic of wooded rolling hills, marshes, old farm fields, and highly
urbanized sections characterize the geography of the area. Soils are predominantly
sandy with scattered gravel deposits. The Huron River, a major Lake Erie
tributary, begins 6 miles northwest of Pontiac Lake and flows through
the lake, entering at the western end and exiting at the dam on the southeastern
shore. Pontiac Lake is 585 acres in size and up to 34 feet deep. It has numerous
islands and peninsulas. The lake bottom is primarily composed of fiberous
peat and other organics with some sand. Over 60% of the lake is 5-feet
deep or less, while approximately 20% is over 10 feet deep. Aquatic vegetation,
including milfoil, has been at nuisance levels since the mid-1970s. Water quality conditions were last surveyed on July 20, 1992. The water
was slightly brown with a Secchi disk reading of 6 feet, indicating moderate
clarity. Within the water column, alkalinity ranged from 126 ppm to 176
ppm and pH ranged from 7.7 to 8.2. These indicated the water is hard and
well buffered. Temperature varied from 69.4°F at the surface to 49.1°F
at the bottom, with the thermocline occurring between 16 and 28 feet.
Typically, summer oxygen levels are sufficient for fish down to a depth
of 18 feet. Overall water quality is good, but limits fish populations
to those suited for shallow, warmwater conditions. Development around Pontiac Lake has been intense. With the exception
of approximately 1 mile of state-owned shoreline on the north side and
extensive marshes at the west end, the shoreline is completely developed
with residential dwellings and associated bulkheads and riprap. Several
of the islands have seasonal or permanent residences on them. A major
highway, M&endash;59, borders the lake at a point on the south shore.
Much of the surrounding area has been highly urbanized with residential
dwellings, businesses, and the Pontiac Airport. A public boat ramp is
located in the State Recreation Area at the east end of the lake. A private
boat ramp and boat rentals/marinas are available at the western end. Shore
fishing is available along the Pontiac State Recreation Area and from
a state fishing pier. According to historical records, fishery management at Pontiac Lake was
limited prior to 1970. A state public fishing site existed prior to 1945.
In 1945, the lake was mapped and a fish survey was conducted. The fish
community included bluegill, pumpkinseed, black crappie, yellow perch,
largemouth bass, and bullhead. A creel census was conducted from spring 1946 through winter 1961-62
to evaluate several changes in fishing regulations (Schneider and Lockwood
1979). During this period, Pontiac Lake supported a strong recreational
fishery. Bluegill and largemouth bass were the primary target species.
In 1947, anglers harvested an amazing 449 bluegill per acre from the lake.
Northern pike were not a major component of the fishery. Bluegill growth
declined over the 16-year period, while largemouth bass and northern pike
growth remained above average. The regulation changes had little apparent
affect on the fish populations in the lake. Tiger musky were introduced in 1970 and added through 1980. Surveys during
this time indicated the species composition of the fish community remained
about the same with an occasional tiger musky, rock bass, and northern
pike included in the samples. Slow panfish growth rates became a concern
in the mid&endash;70's. A panfish thinning project was proposed in 1976,
but was never conducted. In 1980 another creel census was conducted on Pontiac Lake (Ryckman and
Lockwood 1985). Overall fishing pressure, total catch, and catch per hour
had significantly declined since the 1946-62 creel census. Certainly much
of this decline was a result of the substantial decline in the bluegill
fishery. While the bluegill was the primary species sought by Pontiac
Lake anglers in the early census period, the largemouth bass accounted
for 50% of the angler pressure in 1980. Bluegill harvest during the May
to October 1980 period was only 15.3 fish per acre. The change in the statewide largemouth bass size limit in 1976 (10-inch
minimum to 12-inch minimum) and its effect on the bass fishery and population
at Pontiac Lake were examined in 1980 (Goudy 1981). Largemouth bass population
density was found to be about average for similar-size southern Michigan
lakes. Angler harvest of largemouth bass at Pontiac Lake was above average,
but bass mortality rates were slightly below average. The increased minimum
size limit effectively decreased largemouth bass harvest, increased population
size, and provided better fishing for larger bass. In 1981, Pontiac Lake was drawn down 10 feet to facilitate dam repairs.
Due to a series of unfortunate circumstances, the drawdown resulted in
a winterkill of all fish in January, 1982 (Spitler 1984). The lake was
restocked with fathead minnows, largemouth bass, bluegill, black crappie,
yellow perch, northern pike, and channel catfish. A fish survey in 1986
indicated that good numbers of gamefish had been reestablished in Pontiac
Lake, but bluegill and pumpkinseed average size was small. Carp, bowfin,
and bullhead abundance was also undesirably high. Intensive netting in
1987 resulted in the removal of 500 carp during 1 week. Beginning in 1988, catch-and-release fishing for bass was allowed during
April and May (prior to the traditional bass season opener) as part of
a research study. The study found that the early season catch-and-release
fishing did not negatively impact the bass population (Schneider et al.
1991). The study recommended that early season catch-and-release bass
fishing continue at Pontiac Lake. Electrofishing surveys in 1988, 1990, and 1991 indicated continued high
abundance of small bluegill and pumpkinseed. Walleye fingerlings were
stocked in 1990 at a rate of 217 per acre, in an attempt to increase predator
abundance. Follow up surveys indicated walleye experienced very poor survival. Water-based recreation at Pontiac Lake is varied. Power boating, jet
skiing, water skiing, swimming, and duck hunting are all common seasonal
activities. However, dense milfoil growth has prevented many of these
activities from reaching the intensity encountered on many southeast Michigan
lakes. As a result, conflicts between these resource uses and fishing
have been minimal. However, a chemical treatment with Sonar, in May 1992,
greatly reduced macrophyte abundance. In fact, visual surveys in June
and July, 1992, found no live milfoil and very few rooted aquatic plants
of any type. The fish community was most recently surveyed June 1&endash;4, 1992.
The netting effort entailed overnight sets of six trap nets for 3 nights,
overnight sets of two fyke nets for 1 night, and overnight sets of two
gill nets for 1 night. The 1992 survey documented a fish community heavily dominated by small
panfish and carp (Table 1). Combined, bluegill and carp accounted for
92% of the total catch by number, and 88% by weight. Bluegill average length was small at 5.2 inches. Even more disturbing,
only 2% of the bluegill collected were of acceptable size for angling
(larger than 6 inches). In addition, bluegill condition appeared poor
with most individual fish noticably emaciated. Compared with 6-inch bluegill
from Lake Orion, Pontiac Lake fish weighed 28% less. On a scale of 1 to
7 (Schneider 1990), the quality of the Pontiac Lake bluegill population
ranked 1.3, "very poor". By number, carp were second in abundance. By weight, carp dominated the
catch, accounting for 65% of the total weight of fish collected in the
trap nets. Carp average size was 20.5 inches. Only three carp smaller
than 17 inches were collected and it appears that carp reproduction in
recent years has been minimal. Few gamefish were netted. Although low catches of smallmouth and largemouth
bass are expected during summer net surveys, the low numbers of other
gamefish species collected were unexpected. Only a few northern pike and
channel catfish were handled. Largemouth bass were sampled better with a pulsed DC electrofishing boat
on July 27, 1992. During 1.25 hours of shocking after dark, a total of
62 largemouth bass were collected. Nineteen percent of the bass were legal
size (larger than 12 inches). No young-of-the-year and only two age I
fish were collected, suggesting weak year classes for 1991 and 1992. Length
frequency distribution indicates an absence of 12- to 14-inch fish. This
may represent previous weak year classes, or the impact of angler harvest. Growth rates of important game fish species are poor (Table 2). All five
species for which adequate scale samples were collected-bluegill, pumpkinseed,
black crappie, yellow perch, and largemouth bass-are growing well below
state average. Black crappie and bluegill are particularly slow growing. Age composition and survival characteristics of several game fish species
exhibit irregularities (Table 3). Bluegill, pumpkinseed, and yellow perch
are heavily dominated by one or two year classes. Age I largemouth bass
are very poorly represented. Largemouth bass survival from Age IV to Age
V (coinciding with attainment of legal size) is poor. Fishing reports reflect the fish community documented by the 1992 surveys.
While good bass fishing reports are common, very few panfish anglers even
try their luck at Pontiac Lake. Northern pike ice fishing activity has
declined since 1988. In general, the present fish community limits fishing
opportunities. Currently, no active fishery management practices are underway at Pontiac
Lake. If fishing opportunities are to approach their potential, balance
between the predator species and bluegill and carp must be restored. Continued
control of milfoil is needed to allow progress on the bluegill stunting
problem. Our goals for the next 8 years will be to (1) improve the bluegill fishery
as reflected by an increase in the rank from 1.3 to 4.0 on the Schneider
(1990) scale, (2) improve the northern pike fishery by increasing abundance
as indicated by trap net and gill net catch-per-unit effort (CPUE) of
1.0 or higher, (3) maintain the largemouth bass fishery, and (4) decrease
carp abundance as indicated by trap net CPUE of 9.5 or less. Goal Number 1 will likely be the most difficult to attain. However, the
recent success in chemical control of nuisance milfoil growth is promising.
Return of milfoil to nuisance levels will severely impair long term improvement
of the bluegill fishery. The most serious obstacle to goals Number 2 and
3 is excessive angler harvest of northern pike and largemouth bass. The
major obstacle to goal Number 4 is the traditional angler disinterest
in fishing for and harvesting carp. Pontiac Lake's size, shallow depths, severe weed problems, and abundant
human impacts provide serious challenges to improving recreational fishing. Report completed: October 22, 1992. Goudy, G.W. 1981. The exploitation, harvest, and abundance of largemouth
bass populations in three southeastern Michigan lakes. Michigan Department
of Natural Resources, Fisheries Research Report No. 1896. Ann Arbor. Ryckman, J.R. and R. N. Lockwood. 1985. On-site creel surveys in Michigan.
Michigan Department of Natural Resources, Fisheries Research Report No.
1922. Ann Arbor. Schneider, J.C. 1990. Classifying bluegill populations from lake survey
data. Michigan Department of Natural Resources, Fisheries Technical Report
90&endash;10. Ann Arbor. Schneider, J.C., and R.N. Lockwood. 1979. Effects of regulations on the
fisheries of Michigan lakes, 1946-1965. Michigan Department of Natural
Resources, Fisheries Research Report No. 1872. Ann Arbor. Schneider, J.C., J.R. Waybrant, and R.P. O'Neal. 1991. Results of early
season catch-release bass fishing at six lakes. Fisheries Technical Report
91-6. Ann Arbor. Spitler, R.J. 1984. Drawdown related winterkill of Pontiac Lake, Oakland
County, 1981-82. Michigan Department of Natural Resources, Fisheries Technical
Report 84&endash;6. Ann Arbor. Table 1.-Number, weight, and length indices of fish collected
from Pontiac Lake with fyke, gill, and trap nets, June 1-4, 1992.
Table 2.-Average total length (inches) at age, and growth relative
to the state average, for five species of fish sampled from Pontiac Lake
with gill, trap, and fyke nets on June 2-4, 1992, and with electrofisher
on July 27, 1992. Number of fish aged is given in parentheses.
Table 3.-Estimated age frequency (percent) of fish caught from
Pontiac Lake with gill, fyke and trap nets on June 2-4, 1992 and with
electrofisher on July 27, 1992.
Oakland County (T3N, R8 & 9E, Sections 11, 12, 13, 14, 18) MANAGEMENT PLAN Michael V. Thomas Four management goals based on the 1992 survey are detailed below. The
year 2000 is the target date for achieving these goals. Goal number one
is to improve the bluegill population and fishery. A rank of 4.0, or satisfactory,
on a scale of 1 to 7 (Schneider 1990) is the target level. A major factor
in this effort is the continued control of milfoil abundance. Bluegill
population response to vegetative control alone may be substantial. This
response will be evaluated with a fish survey in 1994. Specifically, length&endash;frequencies,
growth rates, and catch rates of bluegill will be compared with previous
survey data. If bluegill response is inadequate future actions might include
partial or total chemical reclamation of the fish community. Goal number two is to improve the northern pike population and fishery
to an abundance level of trap net or gill net CPUE of 1.0 or higher. Northern
pike fingerlings will be stocked on alternate years at a rate of 50 per
acre, beginning in 1993. Year class strength will be evaluated with a
fish survey in 1994. Potential obstacles to achieving this goal include
availability and quality of northern pike fingerlings from the state hatchery
system and excessive harvest of northern pike by anglers. The expected
yield to the fishery is one adult pike per acre, or 585 fish annually. Goal number three is to maintain the existing largemouth bass population
and fishery. No active management is planned to achieve this goal. In
fact, improvement of the bluegill population should benefit bass reproduction
and growth of young bass. Goal number four is to decrease carp abundance about 50%, or trap net
CPUE to 9.5 or less. We should work cooperatively with several local fishing
businesses to establish an annual spring bowfishing contest at Pontiac
Lake, perhaps a two-day weekend event. Secondly, all carp handled in the
1994 survey should be removed from the lake (disposal must be pre-arranged).
Obstacles to this goal include limited angler interest in carp, disposal
problems with quantities of dead carp, and variability of carp catches
in trap nets. Vulnerability of carp to bowfishing should improve with
control of milfoil abundance. Plan completed: September 1, 1992.
Last Update: 08/05/02
tinchert@michigan.gov |