86-5

I T~ F F M.! FOR

FISHERIES

DIVISION

TECHNICAL REPORT

Evaluation of Ice-Cold Water Rotenone Treatment
F of Tipsico Lake

qÃ½7s

Number 86-5
June 23, 1986

I I

Ilr I I III I_-__ I II. i, ~ L I I -1 r~-~peqlg

Michigan Department of
Natural Resources

I.1/

MICHIGAN DEPARTMENT OF NATURAL RESOURCES
FISHERIES DIVISION
Fisheries Technical Report 86-5
June 23, 1986
EVALUATION OF ICE-COLD WATER ROTENONE TREATMENT
OF TIPSICO LAKE
Ronald J. Spitler

ABSTRACT
Tipsico Lake, a 301 -acre warmwater lake in Oakland County, Michigan, was chemically
reclaimed with rotenone on December 11, 1980. Air temperature was 8 0F overnight just prior
to the treatment, changing the previously open -water lake to completely ice covered. Three
boats plowed through the ice for 5 hours to apply 1,210 gallons of synergized rotenone at a
concentration of 1 part per million. By the end of the day, the air temperature was 20OF and
ice thickness was 1.5 inches. The lake remained ice covered and toxic until late March. Too
few fish carcasses were found after the thaw to justify a dead fish cleanup. Test netting,
followed by annual surveys, indicated a total kill. A population of stocked species existed until
unauthorized plants of other species apparently occurred several years later.
This project was unique in that: (1) one -half the usual amount of toxicant was used, yet
a total kill was achieved; (2) ice breaking was required, and accomplished by the boats to apply
the chemical; (3) dead fish estimates were done through the ice by observation; (4) no fish
cleanup was required; (5) the lake remained toxic over 3 months; (6) a population of desired
species was established; and (7) it was accomplished at less than one -half the cost and effort of
a normal fall treatment.

INTRODUCTION
Tipsico Lake is a 301-acre natural lake on the western edge of Oakland County,
Michigan. It is in moranic till, surrounded by rolling hills, and has a small outlet containing a
water level control structure. Permanent homes and summer cottages dot the shoreline, and a
state-owned public launching ramp is located on the west shore.
Maximum depth of the lake is 27 feet with fish-sustaining dissolved oxygen levels to 20
feet in midsummer. Total alkalinity is in the low range for this area (68-95 mg/L), and the pH
averages 8.5. Water clarity is good, with secchi disk readings to 10 feet, but extensive weed
beds dominate the lake wherever it is less than 15 feet deep.
Numerous fishery surveys and angler complaints indicated a population of stunted
panfish and small yellow bullheads. Five-inch yellow bullheads (Ictalurus natalis) constituted
91% of the catch (2,700 out of 2,976 fish handled) in a 1976 netting survey. Bluegills (Lepomis
macrochirus) averaged only 5 inches in length and were over an inch below state average
growth. Largemouth bass (Micropterus salmoides) exhibited similar growth and were not very
abundant.
Approval to chemically reclaim Tipsico Lake was acquired in the fall of 1980. A typical
project takes place in the fall, with the surface water temperature at 60-650F. Two parts per
million rotenone is applied, followed by extensive and costly dead fish cleanup. Detoxification
occurs within a month or two, and a satisfactory, but less than total, kill of fish usually results.
Rotenone remains toxic longer in cold water. The objectives of this study were to
determine if the extended toxicity would result in a complete kill of fish from one-half the
usual amount of chemical, and if the fish would decay under the ice sufficiently to avoid fish
pickup.
METHODS AND MATERIALS
Because of the anticipated cold weather, the plan was to have three boats apply the
toxicant; two to discharge chemical into the propeller wash and one to spray the shallow
shoreline and marsh areas. Sixteen-foot Polarcraft flat-bottom work boats, powered by
15- and 25-horsepower outboard motors, were used. A stake-rack truck hauled the 22 barrels
of rotenone and a front-end loader was available to transfer the barrels from the truck to the
boats. Wooden cradles held two barrels of chemical in each boat. The barrels were elevated
and angled to provide gravity flow through PVC pipe to the propeller wash. Valves on the
barrels controlled the rate of flow of the toxicant. Warm clothes, life jackets, rain gear, and
gloves were used for safety precautions. The treatment was planned for December 11.

Inspection of the lake the day bef ore the scheduled treatment revealed that the lake was
free of ice and the water level had dropped 6 inches or more so that no water was leaving the
lake. However, the air temperature fell to 80F overnight and, upon arrival on site at 9 A.M.
the next morning, the lake was completely ice covered. The project was nearly abandoned, but
a boat with a outboard motor was launched at the ramp, and surprisingly, the boat easily, but
noisily, plowed through the inch -thick ice.
Rotenone application began at 10 A.M. Since the spray rig was now useless, all three
boats were used to meter toxicant into the propeller wash. The lake was divided into thirds for
the three boats, and each operator treated approximately 100 acres.
The day was cloudy but bright; the ice and water very clear, and each boat's treatment
pattern could be seen easily by noting the broken ice lanes. The chemical was obviously evenly
applied. Even without wind or wave action, the rotenone quickly dispersed under the ice. The
white cloudy 'contrail" was plainly visible after each boat pass, only to disappear 15 minutes
later. Shortly after application the surface refroze in the boat lanes.
The 1,210 gallons of chemical were applied in 5 hours. At 3 P.M. the air temperature
was 200F, and ice thickness had reached 1.5 inches in many areas-thick enough to support an
adult.
Sick and dying fish were observed within hours after the treatment began. Because of
the ice cover and quick refreezing where the boats had passed, no dead fish were exposed to the
air. Since there was no wind or current activity to concentrate the carcasses, they stayed where
they died, either just under the ice or on the lake bottom. This presented the unique
opportunity to observe the distribution of a fish population in a lake.
The treatment was evaluated on December 18. There were several inches of clear ice and
only scattered light snow cover, allowing good visibility through the ice. Evaluation teams
divided the lake surface into even parts and each team randomly selected plots to count and
identify fish. The crew leader selected plots by tossing an object (broom, stick, or whatever
was handy) over his shoulder. He then scored a 6-foot diameter circle on the ice at each plot,
using two large nails tied to each end of a 3-foot piece of twine. The plot was cleared of snow
cover. Then, within each circle, the leader identified dead fish by species, both just under the
ice and on the bottom if visible. The numbers were tabulated for each of the 93 sites that were
checked.

three pounds were bluegill and other sunfish (Lepomis spp.); 18 pounds were largemouth bass
and northern pike (Esox lucius); 20 pounds were bullheads; and 25 pounds were bowfin (Amia
calva), pickerel (Esox americanus), minnow (Cyprinidae), and other species.
Two sets of cages with live fish were placed from top to bottom in the deepest basins, in
early and late January. All fish died within 48 hours. The ice disappeared on April 1, 1981,
and test cages set on April 7 contained live fish after 72 hours. A strong southerly wind drifted
several hundred dead fish to the north shore just after ice out, but all the carcasses disappeared
within days. Eight gill nets, set for 3 nights (24 net nights), April 10-13, 1981, took no fish.
FISH PLANTING AND RESULTS
Throughout the 1981 field work season 1,268 adult bluegills; 104 adult black crappies
(Promoxis nigromaculatus); 15,888 fingerling largemouth bass; 18 adult largemouth bass;
19,729 fingerling channel catfish (Ictalurus punctatus); 1,900 fingerling tiger muskellunge
(Esox masquinongv x Esox lucius); and 50 pounds of minnows were stocked. Tiger musky
plants continued on a semiannual basis.
Tipsico Lake was surveyed several times during the 3 years following the treatment.
Survey effort consisted of many hours of electrofishing and 46 net nights of trap and fyke
netting. Over 6,600 fish were handled and countless others were seen. Only 1 green sunfish
(Lepomis cyanellus), 1 mudminnow (Umbra limi), and 21 pumpkinseed sunfish (Lepomis
gibbosus) were found in addition to the species planted. The sunfish may have been mixed in
with the panfish originally planted, although the quality control was believed good. The
surveys and angler reports indicate that both the fish population and fishing are much better
than before the treatment. The boat access site is filled with angler boat trailers each weekend
during the fishing season, and a privately owned boat livery reports that business is good.
DISCUSSION
The success of the cold-water rotenone treatment of Tipsico Lake lies not solely in the
fact that it was highly effective, but in several other aspects as well. Following is a comparison
of this project with what would have been a normal fall treatment of the same lake, with
estimates of effort required for clean-up and evaluation.

Fall treatment Cold -water treatment
Chemical ($13.25/gal) $32,065 (2,420 gal) $16,032 (1,210 gal)
Treatment ($80/man-day) 1,280 (16 man-days) 1,280 (16 man-days)
Evaluation ($80/man-day) 480 (6 man-days) 480 (6 man-days)
Clean-up ($80/man-day) 960 (12 man-days, est.) 0 (man-days)
Totals $34,785 $17,792
The total estimated costs yield cost-per-acre comparisons of $116 (fall treatment) versus
$59 (cold water). The savings on the Tipsico Lake project were approximately $16,000 in
chemical costs and 12 man-days (~$1,000) in effort. Considering the additional savings in
labor, expense, and inconvenience to the water front residents, the values are much greater.
With the dead fish under the ice all winter, and many decomposed before spring, there were no
windrowed carcasses littering the shoreline to arouse complaints.
Future fish reclamation projects of this type can be planned by monitoring air and water
temperatures, relating them to weather projections, and attempting to predict when ice cover
will occur. It is the manager's choice as to when to treat. If the chemical is applied in open
water, but very close to ice cover, there is a risk of some dead fish cleanup, but chemical
effectiveness is not in doubt. If the lake has first ice, there is always the possibility that the ice
will be too thick to plow with the boats, in which case the project must be cancelled until the
next season. There is no doubt that effective projects such as Tipsico Lake can be
accomplished in the same manner with proper planning and careful temperature monitoring.
Considering the savings in cost and effort, chemical efficacy, and improved public
relations, this seems to be a method to be tried.
ACKNOWLEDGMENTS
The author is indebted to the following for their assistance: fisheries bioliogists
Raymond Shepherd and William Deephouse; fisheries technicians Ralph Hamilton, Vernon
Nurenberg, and Kenneth Downing for their enthusiastic efforts in conducting the treatment
and evaluation; fisheries technicians James Waybrant, Dann Manz, and biologist Andrew
Nuhfer for their assistance in survey work; secretaries Barbara Rockwell and Barbara Gould
for typing the various drafts of this manuscript; and W. C. Latta and James Merna, without
whose editing and approval this would not have become a technical report.

LITERATURE CITED
Schneider, J. C. 1973. The standing crop of fish in Michigan lakes. Michigan Department of
Natural Resources, Fisheries Research Report 1794, Ann Arbor, Michigan, USA.
Schneider, J. C. 1978. Predicting standing crops of fish in Michigan lakes. Michigan
Department of Natural Resources, Fisheries Research Report 1860, Ann Arbor,
Michigan, USA.
Report approved by W. C. Latta

Typed by G. M. Zurek

lot

i/li