INVESTIGATIONS IN FISH CONTROL

25. Field Trials of Antimycin 

as a Selective Toxicant

in Channel Catfish Ponds

26. Laboratory Studies on Antimycin A 

as a Fish Toxicant

27. Field Trials of Antimycin A 

as a Fish Toxicant

28. Use of Antimycin

for Selective Thinning of 

Sunfish Populations in Ponds

United States Department of the Interior

Fish and Wildlife Service 

Bureau of Sport Fisheries and Wildlife
INVESTIGATIONS IN FISH CONTROL

Investigations in Fish Control, published by the Bureau of Sport Fisheries and Wildlife, include reports on the results of work at the Bureau's Fish Control Laboratories at La Crosse, 

Wis., and Warm Springs, Ga., and reports of other studies related to that work. Though each 

report is regarded as a separate publication, several may be issued under a single cover, for 

economy.

Current reports in this series are 

(Reports 1 and 2 are in one cover.)

1. Laboratories and Methods for Screening Fish-Control Chemicals, by Robert E. Lennon 

and Charles R. Walker. 1964. 15 p.

2. Preliminary Observations on the Toxicity of Antimycin A to Fish and Other Aquatic 

Animals, by Charles R. Walker, Robert E. Lennon, and Bernard L. Berger. 1964. 18 p.

(Reports 3 through 8 are in one cover.)

3. Minimum Lethal Levels of Toxaphene as a Piscicide in North Dakota Lakes, by Dale L. 

Henegar. 1966. 16 p.

4. Effects of Toxaphene on Plankton and Aquatic Invertebrates in North Dakota Lakes, by 

Robert G. Needham. 1966. 16 p.

5. Growth Rates of Yellow Perch in Two North Dakota Lakes After Population Reduction with 

Toxaphene, by Donald C. Warnick. 1966. 9 p.

6. Mortality of Some Species of Fish to Toxaphene at Three Temperatures, by Mahmoud 

Ahmed Mahdi. 1966. 10 p.

7. Treatment of East Bay, Alger County, Michigan, with Toxaphene for Control of Sea 

Lampreys, by William E. Gaylord and Bernard R. Smith. 1966. 7 p.

8. Effects of Toxaphene on Fishes and Bottom Fauna of Big Kitoi Creek, Afognak Island, 

Alaska, by William R. Meehan and William L. Sheridan. 1966. 9 p.

(Reports 9 through 11 are in one cover.)

9. Relation of Chemical Structure to Fish Toxicity in Nitrosalicylanilides and Related Compounds, by Charles R. Walker, Roland J. Starkey, and Leif L. Marking. 1966. 12 p.

10. Evaluation of p,p'-DDT as a Reference Toxicant in Bioassays, by Leif L. Marking.

1966. 10 p.

11. Evaluation of an Electronic Method of Measuring Hematocrits of Fish, by Richard A. 

Schoettger and Arnold M. Julin. 1966. lip.

(Reports 12 through 17 are in one cover.)

12. Toxicity of MS-222 to Selected Fishes, by Leif L. Marking. 1967. 10 p.

13. Efficacy of MS-222 as an Anesthetic on Four Salmonids, by Richard A. Schoettger and 

Arnold M. Julin. 1967. 15 p.

14. Method for Determining MS-222 Residues in Fish, by Charles R. Walker and Richard A. 

Schoettger. 1967. 10 p.

15. Residues of MS-222 in Four Salmonids Following Anesthesia, by Charles R. Walker and 

Richard A. Schoettger. 1967. lip.

16. Annotated Bibliography on MS-222, by Richard A. Schoettger. 1967. 15 p.

17. MS-222 as an Anesthetic for Channel Catfish: Its Toxicity, Efficacy, and Muscle Residues, 

by Richard A. Schoettger, Charles R. Walker, Leif L. Marking, and Arnold M. Julin.

1967. 14 p.

Fish Control Laboratories

Bureau of Sport Fisheries and Wildlife

U.S. Department of the Interior

P.O. Box 862

La Crosse, Wisconsin 54602

Continued on inside back cover 
INVESTIGATIONS IN FISH CONTROL

25. Field Trials of Antimycin as a Selective Toxicant 

in Channel Catfish Ponds

By Ralph M. Burress and Charles W. Luhning

26. Laboratory Studies on Antimycin A as a Fish Toxicant

By Bernard L. Berger, Robert E. Lennon, and James W. Hogan

27. Field Trials of Antimycin A as a Fish Toxicant

By Philip A. Gilderhus, Bernard L. Berger, and Robert E. Lennon

28. Use of Antimycin for Selective Thinning of 

Sunfish Populations in Ponds 

By Ralph M. Burress and Charles W. Luhning

United States Department of the Interior

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Washington, D.C. . February 1969
IN THIS COVER

Pages

Field Trials of Antimycin as a Selective Toxicant in Channel

Catfish Ponds, by Ralph M. Burress and Charles W. Luhning . . . 1-12

Laboratory Studies on Antimycin A as a Fish Toxicant, by

Bernard L. Berger, Robert E. Lennon, and James W. Hogan. . . . 1-19

Field Trials of Antimycin A as a Fish Toxicant, by Philip A.

Gilderhus, Bernard L. Berger, and Robert E. Lennon ........ 1-21

Use of Antimycin for Selective Thinning of Sunfish Populations

in Ponds, by Ralph M. Burress and Charles W. Luhning. ...... 1-10

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 65 cents

11
INVESTIGATIONS IN FISH CONTROL

25. Field Trials of Antimycin 

as a Selective Toxicant 

in Channel Catfish Ponds

By Ralph M. Burress, Fishery Biologist and

Charles W. Luhning, Physical Science Technician

United States Department of the Interior

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Washington, D.C. . February 1969
CONTENTS

Page

Abstract. ....................................... 3

Methods and materials .............................. 4

Experiment design .............................. 4

Description of ponds ............................. 4

Sampling and harvesting .......................... 4

Application of toxicant. ........................... 5

Degradation of toxicant ........................... 5

Results. ......................./................ 6

First treatment ................................ 6

Second treatment ............................... 7

Scalefish in treated ponds at harvest .................. 7

Scalefish in untreated ponds at harvest. ................ 8

Harvest of channel catfish ......................... 8

Discussion ...................................... 9

Conclusions. ..................................... n

References ......................................
FIELD TRIALS OF ANTIMYCIN AS A SELECTIVE 

TOXICANT IN CHANNEL CATFISH PONDS

By Ralph M. Burress, Fishery Biologist 

and Charles W. Luhning, Physical Science Technician

Bureau of Sport Fisheries and Wildlife 

Southeastern Fish Control Laboratory, Warm Springs, Georgia

ABSTRACT. Antimycin effectively and economically controlled heavy 

infestations of green sunfish and golden shiners from selected channel 

catfish ponds at a Mississippi fish farm. An initial application of 5 p.p.b. 

of antimycin in two ponds and 7.5 p.p.b. in the third pond eliminated nearly 

99 percent of the scalefishes. A followup treatment of 10 p.p.b., 4 days 

later, further reduced these populations with no apparent effect on yearling 

catfish. At harvest, three untreated ponds produced 1,474 pounds of scalefishes or an average of 389 pounds per acre, yielded 27.4 percent or 1,155 

fewer catfish than the three treated ponds, and contained 1,183 undersize 

fish or nearly three times as many that were too small for table use. 

Comparison of the adjusted yields of catfish from treated and untreated 

ponds, ranging in size from 0.94 to 1.39 acres, indicates that treated 

ponds produced an additional 1,015 pounds of fish worth $507.50, while 

antimycin cost only $145.79 a net return of $2.48 for each dollar invested in toxicant.

To those engaged in commercial production 

of channel catfish, the presence of undesirable 

species of scalefishes in rearing ponds is a 

potentially serious problem. The Bureau of 

Commercial Fisheries (1966) reports that 

about 35 million pounds of catfish are raised 

annually in the United States, and predicts 

that commercial production can reach 60 million pounds per year. The rapidly increasing 

demand has induced numbers of pond owners 

to undertake catfish production, but many have 

experienced losses caused by undesirable 

species of fish in broodponds and rearing 

ponds. Meyer (1965) discussed the nature of 

these losses, and reported the results of experiments in which various organophosphate 

insecticides were tested to determine whether 

they could be utilized for selective removal of

trash fish from ponds used to produce catfish 

or bigmouth buffalo.

The purpose of this study was to evaluate 

the effectiveness of antimycin in controlling 

undesirable scalefishes in soft-water ponds 

used for commercial production of catfish, 

and to measure benefits derived from the 

treatment. The work was done in 6 of 14 dug 

ponds at a private fish-farm in Columbus, 

Miss., during the period August 1, 1966, to 

January 25, 1967.

Our sincere thanks are expressed to the 

following whose cooperation made this study 

possible: Mr. Ruben Prescott, owner of the 

ponds; Wisconsin Alumni Research Foundation, owner of antimycin; and Ayerst Laboratories, New York, producer of antimycin.
Investigations in Fish Control 25; Bureau of Sport Fisheries and Wildlife

METHODS AND MATERIALS

EXPERIMENT DESIGN

The owner of the farm assisted us in selecting three pairs of ponds similar in size, depth, 

severity of infestation by scalefishes, and 

average size of channel catfish.

The field work was done in two stages. The 

first stage, done in August, included (1) sampling of the fish populations in six ponds by 

seining, (2) applying antimycin in the Fintrol5 formulation to three ponds, and (3) recovering scalefishes from the treated ponds. The 

second stage, in October and January, involved (1) draining all ponds, (2) analyzing 

fish populations, and (3) evaluating the results of the treatment.

DESCRIPTION OF PONDS

The ponds ranged from 0.94 to 1.39 acres 

in surface area (table 1). They were steep 

sided and each had a scooped catch basin at 

the deep end measuring about 15 by 40 by 2 

feet. The maximum depth outside the catch 

basin in the first two pairs of ponds was about

TABLE l. Some physical and chemical characteristics of 

three ponds treated with antimycin

TABLE 2. Characteristics of water in three treated ponds1

Characteristic

Surface area

Average depth. .............. feet. . 

Volume. ............... .acre-feet. . 

Secchi disk transparency. .inches. . 

Temperature (celsius) at 7:30 a.m:

2........................

3........................

pH Aug. 1: 

7:45-8:30 a.m. ................

2:30-3:00 p.m. ................

pH Aug. 2: 

7:45-8:30 a.m. ................

2:30-3:00 p.m. ................

5:45-6:30 p.m. ................

pH Aug. 3: 

7:45-8:30 a.m. ................

2:30-3:00 p.m. ................

5:45-6:30 p.m. ................

Pond 1

0.94

5.25 

4.94 

7

30°

30°

28°

8.2

10.1

8.5

9.9

9.7

7.3

Pond 3

1.26

5.20 

6.93

12

30°

30°

28°

7.3

7.5

9.4

7.5

9.5

9.2

Pond 5

1.17

3.50 

4.10 

14

30°

30°

28°

7.7

9.4

7.1

9.4

9.4

6.9

Characteristic

Resistivity (26.6° C. ).............

pH.................................

Pond 1

11,500 

10.5 

22.0 

20.0 

9.2 

4.5 

0.1 

0.9 

Trace 2 

0.3

Pond 3

12,500

10.3 

19.0 

20.0 

10.0 

7.0 

0.2 

1.4 

0.02 

0.3

Pond 5

13,000 

10.8 

20.0 

14.0 

6.0 

4.0 

0.5 

1.0 

0.28 

1.1

1 Samples taken at 4:00 p.m., August 8, refrigerated, and 

tested at Warm Springs on August 10 by standard methods of 

analysis.

2 Trace = less than 0.01 p.p.m.

7 feet, while that in the third pair was only 5 

feet.

These ponds contained relatively soft water 

with total hardness ranging from 14 to 20 

p.p.m. (as CaCO3>, and pH values were quite 

high (table 2). The other chemical characteristics indicate that Pond 5 was somewhat 

more fertile than Ponds 1 and 3. Ponds 1 and 

5 received water from a well, while Pond 3 

was filled from a deep, open pit which contained scalefishes.

None of the ponds contained growths of 

filamentous algae or submersed aquatic vegetation. However, each supported a dense 

bloom of phytoplankton, which caused marked 

rises in pH values each day. The addition of 

25 pounds of commercial catfish feed per day 

per pond contributed to development of the 

blooms, and produced noticeable accumulations of organic matter on the bottom in the 

feeding areas.

Each pond was stocked in 1965 or 1966 

with about 2,000 fingerling channel catfish 

(Ictalurus punctatus). In addition, all the 

ponds contained golden shiners (Notemigonus 

crysoleucas) and green sunfish (Lepomis 

cyanellus). The open-pit water supply was 

populated by golden shiners, warmouth bass 

(Chaenobryttus gulosus), green sunfish, and 

bluegills (Lepomis macrochlrus).

SAMPLING AND HARVESTING

Average lengths and weights of the catfish 

at the time of treatment were calculated from 

a sample of about 50 fish from each pond
Duress and Luhning: Antimycin in Channel Catfish Ponds

TABLE 3. Numbers, weights, and percentages of channel

catfish sampled in August in each of three pairs of ponds; 

the designations (T) and (U) identify treated and untreated ponds

TABLE 4.--Number of scalefish of each size group sampled by 

seining in each of three pairs of ponds (the two size 

groups represent fish hatched in pond and initial 

invaders)

Pond

1 (T).... 

2 (U)....

3 (T).... 

4 (U)....

5 (T).... 

6 (U)....

Date 

of 

stocking

10/23/65 

9/06/65

10/23/65 

2/09/66

11/09/65 

11/09/65

Number 

of 

fish

48

51

47 

29

56 

47

Percent of 

population 

sampled 1

2.4

3.1

2.8

3.0

3.4 

2.9

Weights (Ibs.)

Total

33.40 

44.00

24.25 

6.25

17.50 

19.25

Average

0.70 

0.86

0.52 

0.22

0.31 

0.41

1 Based on number of fish recovered at harvest.

(table 3). When possible, the fish were taken 

with a 30-foot, 1-inch-mesh seine, which was 

stretched out just beyond the feeding area and 

hauled in rapidly while the fish were feeding. 

This technique worked very well in Ponds 5 

and 6, which are comparatively shallow, but 

in the deeper ponds these samples had to be 

augmented by catches made with a 125-foot, 

1-inch-mesh seine or with a 250-foot, 1-inchmesh gill net. The size of the sample in Pond 

4 was reduced because the water was too 

deep for effective seining, and gill netting 

would have killed too many fish. The reduction in sample size was not regarded as 

serious, since the fish were uniform in length 

and weight.

Scalefish populations were sampled to obtain an estimate of their abundance in each 

pond. Two 40-foot hauls were made with a 

20-foot, 1/4-inch-mesh seine, and the fish 

were enumerated by species and discarded 

(table 4).

Five of the six ponds were harvested in 

January 1967. All of the catfish were counted 

and weighed. We also made a fairly accurate 

measure of the scalefish even though some 

were lost in the mud.

Pond 2 was drained by the owner of the fish 

farm on October 3 to meet an urgent need for 

catfish in his restaurant. The number and 

dressed weight of the catfish were recorded, 

and the live weight was computed from these 

figures. Although scalefishes were not collected at the time of harvest, an estimate of 

their numbers was made.

1....

2....

3....

4....

5....

6....

Green sunfish

1-1.5 in.

321

338

1,410

547

653

2-6 in.

6

14

0

50

13

scores 1

Golden shiners

1.5-2.25 in.

1,510

543

0

16

25

3-4.5 in.

1

0

0

0

0

hundreds 1

Tadpoles

0

0

238

0

0

1 Seining data misplaced.

APPLICATION OF TOXICANT

At the time of treatment, the water temperature was above 60° F. and the pH was less 

than 8.5, hence a concentration of 5 parts per 

billion (p.p.b.) of antimycin in the Fintrol-5 

formulation was selected in accordance with 

the manufacturer's recommendation. The 

toxicant was applied from a boat with a handoperated seed spreader. Treatment of each 

pond was accomplished in 15-20 minutes 

between 7:45 and 9:00 a.m. on August 2. We 

added a supplementary treatment of 2.5 p.p.b. 

of antimycin to Pond 1 at 9:30 a.m. when we 

discovered that the pH had risen to 8.5 by 

8:30 a.m.

We observed on August 4 that a few scalefish had survived in treated ponds, hence 

10 p.p.b. of antimycin were applied to each 

pond on August 5 in an effort to determine the 

remnant populations and obtain a better evaluation of the results of the first treatment. 

These applications were completed between 

6:05 and 7:15 a.m., which gave the antimycin 

almost 2 hours longer to take effect before 

the diurnal elevation in pH occurred. We recovered all the dead fish within 3 days after 

each treatment.

DEGRADATION OF TOXICANT

Golden shiners and fingerling green sunfish were seined from Pond 6, and 10 fish of 

each species were placed in live-boxes in the 

treated ponds about 24 hours after each application of the toxicant. We considered that 

degradation of the toxicant was complete when 

all of the fish survived a 48-hour exposuie in 

the treated water.
6 Investigations in Fish Control 25: Bureau of Sport Fisheries and Wildlife

RESULTS

FIRST TREATMENT

Small green sunfish and golden shiners 

were surfacing and gulping air within 15 minutes after we completed the applications of 

antimycin. Within 3 hours adult fish of both 

species began surfacing, and some could be 

taken easily with a dip net. Most of the golden 

shiners and a substantial proportion of the 

small green sunfish were recovered on the 

day of treatment. Larger fish of each species 

were slower to appear.

We observed several green sunfish in each 

pond which were too alert and active to be 

captured by dip net at 6:00 p.m. on the day of 

treatment. This was the first indication that 

the treatment was not completely successful. 

Although collections of fish were good for the 

next 2 days, the degradation of the toxicant 

was essentially complete within 24 hours 

after application as shown by tests with caged 

fish.

The first application of antimycin was 

highly effective in removing scalefish populations regardless of their composition 

(table 5). In Pond-1 we recovered about 187 

pounds of scalefish per acre. Golden shiners 

were dominant, comprising 88.4 percent by 

number and 78.8 percent by weight. In Pond 3 

fingerling green sunfish amounting to 146 

pounds per acre constituted more than 99 

percent of the scalefish population by number 

and weight. In Pond 5 the population was comparatively small, amounting to only 44 pounds 

per acre. Green sunfish of both sizes comprised more than 99 percent of the population 

by number and weight.

In order to check on the completeness of 

the kill, we again used the technique of seining 

at the time of feeding. It was interesting to 

see that several adult green sunfish which 

survived exposure to 5.0 and 7.5 p.p.b. concentrations of antimycin just 2 days earlier 

were not off feed, but responded with characteristic quickness to the familiar sound of 

food pellets hitting the water.

TABLE 5. Total numbers and weights in pounds (in parentheses) of scalefish recovered following the first and second

applications of antinycin

size groups

Golden shiner: 

1 5 4 5 inche s

Warmouth :

Green sunfish:

Bluegill:

TOTAL. .....................

First 

(7.5 p.p.b.)

31,435

(138.2)

(0.4) 

3,858

(20.2)

(10.4) 

1

(0.5) 

35,489

(169.7)

Pond 1

Second 

(10 p.p.b.)

(Trace) 1 

7

(1.5) 

9

(0.1) 

52

(4.2) 

0

70

(5.8)

Total

31,437

(138.2) 

10

(1.9)

(20.3) 

244

(1A.6) 

1

(0.5) 

35,559

(175.5)

First 

(5 p.p.b.)

25

(0.3) 

0

59,840

(178.0)

(0.3) 

0

(178.6)

Pond 3

Second 

(10 p.p.b.)

12

(0.1) 

0

1,019

(5.5) 

3

(0.3) 

0

1,034

(5.9)

Total

37

(0.4) 

0

60,859

(183.5) 

5

(0.6) 

0

60,901

(184.5)

First 

(5 p.p.b.)

65

(0.3) 

0

9,526

(19.8) 

1,133

(31.3) 

0

10,724

' (51.4)

Pond 5

Second 

(10 p.p.b.)

0

0

3

(Trace)

(0.8) 

0

18

(0.8)

Total

(0.3) 

0

9,529 

(19.8)

1

-1 i rt

(32.1) 

0

(52.2)

1 Trace = less than 0.1 Ib.
Burress and Luhning: Antimycin in Channel Catfish Ponds

SECOND TREATMENT

Within 3 hours after the treatment with 

10 p.p.b. of antimycin, it was evident that the 

first treatment had eliminated most of the 

golden shiners in each pond. Our final count 

showed that the following percentages of 

golden shiners had survived: Pond 1, less 

than 0.01 percent; Pond 3, 32.4 percent; 

Pond 5, 0.0 percent. More than 99.7 percent 

of the small green sunfish were eliminated in 

Ponds 1 and 5; only 9 and 3 fish were recovered in each, respectively. In Pond 3, 

1,019 small green sunfish had survived or 

1.67 percent of the total number recovered.

Recovery of 52 green sunfish from 2 to 6 

inches long in Pond 1 was unexpectedly high, 

amounting to 21.3 percent of the total number 

of this size group taken. In Pond 3 we found 

that 3 of 5 adult green sunfish had survived, 

while in Pond 5 we recovered only 15 of the 

1,148 adult fish originally present.

Seven of 10 adult warmouth taken from 

Pond 1 had survived the first treatment, 

whereas the single large bluegill present did 

not.

Tadpoles began to die in Pond 3 shortly 

after the second treatment was made, and in 

2 days we recovered about 1,990 tadpoles 

weighing 33.25 pounds. What percentage of 

the population this represented is not known, 

but a complete kill did not occur.

Degradation of antimycin was complete in 

all three ponds within 48 hours after application.

SCALEFISH IN TREATED PONDS AT 

HARVEST

Antimycin treatments were highly successful in that no golden shiners or warmouth 

were found in Ponds 1 and 3, and the reduction of green sunfish in each pond was more 

than 99.99 percent complete (table 6). Since 

there was no exchange of water between these 

two ponds and untreated ponds, we assume 

that the green sunfish had survived the treatment.

Unfortunately the exact results of the treatment of Pond 5 were obscured because an 

undetermined number of scalefish were carried in subsequently by an overflow from an 

adjacent pond. Since no golden shiners were 

recovered in this pond following the second 

application of antimycin, and since no 

warmouth were found following either treatment, we are virtually certain that the few 

individuals of each species which were observed at harvest were post-treatment 

invaders. The bottom of this pond was exceptionally flat, and contained scores of shallow 

depressions in the deep, soft mud. Thousands 

of green sunfish, many of which had hatched 

following the treatments, were trapped, and 

we could not make an accurate assessment of

TABLE 6. Total numbers and total weights in pounds (in parentheses) of scalefish 

recovered at draining

Species and 

size groups

Golden shiner: 

2.5-5.5 inches......

Green sunfish:

TOTAL

Treated ponds

1

0

0

4

(1.5)

0

0

4 

(1.5)

3

0

2 

(0.2) 

7 

(1.2)

(0.5) 

0

10 

(1.9)

5

Very few 1

3 1,000's 

3 150-200

0 

Very few1

Untreated ponds

2

2 50,000 

(253)

2 40,000 

(125) 

0

0

0

90,000 

(378)

4-

1,428 

(50)

39,740 

(344) 

2,421 

" (178)

0

0

43, 589 

(572)

6

31,680 

(308)

18,627 

(186) 

170 

(29)

0

3

(1.0) 

50,480 

(524)

1 Probably carried in by overflow from adjacent pond.

2 Number estimated by pond owner at draining; all sizes included.

3 Numbers estimated because many small fish were lost in soft mud; some probably carried in 

by overflow from adjacent pond.

338-447 O -
8 Investigations in Fish Control 25: Bureau of Sport Fisheries and Wildlife

the numbers of green sunfish present. An 

estimated 150-200 green sunfish from 3.5 to 

6.0 inches in length were seen, many of which 

must have survived the antimycin treatments. 

Even if we assume that there were 200 and 

that none had immigrated into the pond, there 

was a reduction of more than 98.12 percent 

in the numbers of green sunfish originally 

present.

SCALEFISH IN UNTREATED PONDS AT 

HARVEST

Large numbers of scalefish were found 

when the untreated ponds were drained 

(table 6). In Pond 4 green sunfish weighing 

418 pounds per acre comprised 91.3 percent 

of the scalefish population by weight, and 

large golden shiners amounting to about 40 

pounds per acre made up the remainder. In 

Pond 6 golden shiners weighing 268 pounds 

per acre made up 58.8 percent of the total 

weight, and green sunfish weighing 187 pounds 

per acre comprised 41.2 percent of the total 

weight. The pond owner estimated that there 

were 40,000 green sunfish and 50,000 golden 

shiners of several sizes in Pond 2 at harvest. 

If weight data obtained during our sampling 

of the population 2 months prior to harvest 

were applied to this estimate, we can calculate that about 90 pounds of green sunfish and 

182 pounds of golden shiners were removed 

per acre. In all three of these ponds there

were hundreds of scalefish large enough to 

compete directly with the catfish for food.

HARVEST OF CHANNEL CATFISH

Three treated ponds having a combined 

area of 3.37 acres produced 5,363 catfish 

weighing 4,855 pounds, and the three untreated ponds having a combined area of 3.79 

acres produced 4,208 catfish weighing 3,088 

pounds (table 7). The average weight of catfish in the treated and untreated ponds at 

harvest was 0.91 and 0.73 pounds, respectively. We sorted out the smallest fish from 

each pond, which weighed from about onethird to one-half pound, and placed them in a 

single pond for additional feeding. Among the 

treated ponds, the number of undersize fish 

ranged from 81 to 226 with a total number of 

421, while in the two untreated ponds for 

which data are available, the numbers of such 

fish were 235 and 948 for a total of 1,183. The 

differences are quite pronounced, but not all 

of them can be attributed solely to the treatment. Some were caused by variations in 

time of stocking, degree of competition from 

scalefish populations, and rates of catfish 

survival which may have been influenced 

strongly by predation. In the following section, an attempt is made to evaluate the effects produced by these factors and to 

arrive at a conservative measure of the 

benefits derived from treatment.

TABLE 7. Numbers and weights in pounds of channel catfish harvested from treated and untreated ponds

Pond

Area 

(acres)

Date

of 

stocking 1

Date

of 

harvest

Harvest per pond

Total

Number Weight Number Weight

Average weight

August 

sample

At

harvest

Percent 

gain in 

weight

Undersize fish

Number Av. wt. Percent

Treated Ponds:

1. .....

3......

5......

TOTAL

0.94

1.26

1.17

3.37

10/23/65

10/23/65

11/09/65

1/12/67

1/04/67

1/16/67

2,036

1,701

5,363

2,438

4,855

2,166

1,350

1,389

2 594

Ctf-.f-.

1,026

0.70

0.52

0.31

1.20

0.72

71.1

1 O£ r~J 114

421

0.35

0.55

0.37

4.8

7.0

Untreated Ponds:

TOTAL

1.39

1.25

1.15

3.79

9/06/65

2/09/66

11/09/65

10/03/66

1/24/6? 

1/25/67

1,625

978

1,605

1,527

335

1,226

4,208 3,088

1,169

782

1,396

1,099

268

1,066

0.86

0.22

0.41

0.94

0.34

0.76

3 9.3

54.4

85.4

948

235

1,183

No data 

0.33 

0.46 14.6

1 Fingerling channel catfish 2.5 inches long stocked in all ponds.

2 When total weight and weight per acre of catfish harvested from Pond 2 were adjusted to compensate for the difference in 

time of harvest, they became 1,735 and 1,248 pounds, respectively.

3 Percent gain in weight from sampling on August 1 to harvest on October 3.
Burress and Luhning: Antimycin in Channel Catfish Ponds 9

DISCUSSION

This field trial demonstrated quite clearly 

that antimycin can be used to control scalefishes in soft-water ponds without killing catfish, and that the investment in the treatment 

was well compensated by greater production 

in treated ponds. The initial treatment was 

nearly 99 percent effective, and there is good 

reason to believe that its efficacy would have 

been enhanced had the application of Fintrol-5 

been made at daybreak. This would have allowed a substantially greater amount of 

exposure time before the rapid rise in pH 

began to cause degradation of the toxicant. 

Berger, Lennon, and Hogan (1969) found that 

the effectiveness of antimycin against fish is 

influenced substantially by the pH of the 

medium. Results of their bioassays indicated 

that the concentration of antimycin required 

to produce a complete kill of fingerling goldfish in 96 hours at 12° C. was 0.20 p.p.b. at 

pH 5, 1.10 p.p.b. at pH 8, and 60 p.p.b. at pH 

10.

Scalefish populations can be controlled at 

any time of the year, since water temperature 

has comparatively little effect on the efficacy 

of antimycin, and even fingerling catfish are 

not killed by recommended levels of treatment. Obviously such treatments yield greater 

benefits if accomplished a few days before 

ponds are stocked or soon thereafter.

It is thought that more green sunfish survived in Pond 5 because the water was comparatively shallow, and the bottom was 

completely covered by very soft mud. The 

sand formulation of antimycin used is designed to release the toxicant at a uniform 

rate as it sinks through the first 5 feet of 

water. Since the average depth of the pond 

was only 3.5 feet, a substantial percentage of 

the antimycin was not released before the 

sand sank into the mud. Therefore, we do not 

recommend lowering hatchery-type ponds 

prior to treatment if their average depths 

are not in excess of 5 feet.

The calculations of benefits cannot be based 

simply on the difference in total weights of 

catfish harvested from each group of ponds 

for two reasons: (1) Pond 6 was stocked much

later than any of the others, and survival of 

the fish was by far the poorest in this pond; 

and (2) Pond 2 was harvested far earlier than 

the others. Thus, the most conservative approach to assessing the benefits derived 

from the treatment appears to be that of direct comparison of weight gains made by catfish in each pair of ponds after the time of 

treatment.

In comparing catfish populations and production in the first pair of ponds, we find that 

untreated Pond 2 was stocked on September 6, 

1965, or about 47 days before Pond 1. Thus, it 

is not surprising that the average weight of 

catfish in the untreated pond was 0.16 pounds 

or 22.9 percent greater at the August sampling. The advantage of earlier stocking, however, was largely negated by the tremendous 

increase in competition from hundreds of 

scalefishes which grew large enough to consume food pellets.

Although treated Pond 1 was harvested 101 

days later than Pond 2, the following adjustment can be made to permit a meaningful 

comparison of the gains in weight after the 

time of treatment. The average weight of catfish in Pond 2 increased by 9.3 percent between sampling time on August 1 and harvest 

time on October 3, hence the weight gain of 

the entire catfish population during this 63- 

day period was about 130 pounds. By subtracting this figure from the harvest figure, 

we can calculate that their total weight on 

August 1 was about 1,397 pounds. If we then 

make the generous assumption that the catfish in Pond 2 would have continued to gain 

weight at the same rate during the increasingly cold months of October, November, and 

December, their total gain from August 1 to 

January 12 would have been 338 pounds, and 

their adjusted total weight in January would 

have been 1,735 pounds. By comparison the 

total weight of catfish in Pond 1 on August 1 

was about 1,425 pounds, and their weight at 

harvest was 2,438 pounds. Thus, their gain 

amounted to 1,013 pounds, or 675 pounds 

more than the adjusted weight gain by the 

catfish in Pond 2.

The comparison of catfish production in the 

second pair of ponds is complicated by the
10 Investigations in Fish Control 25: Bureau of Sport Fisheries and Wildlife

fact that Pond 3 was stocked on October 23, 

1965, and untreated Pond 4 was stocked 109 

days later on February 9, 1966. Catfish in 

the latter pond were further handicapped, because it contained by far the greatest population of adult green sunfish throughout the year 

as indicated both by seining in August and by 

the recovery of scalefishes at harvest. Under 

these circumstances it is not surprising that 

less than half of the original stock of catfish 

survived, that their average weight in August 

was only 0.22 pounds, or that 96.9 percent of 

them failed to reach marketable size by harvest time. Catfish in treated Pond 3 gained a 

total of 332 pounds following treatment while 

those in Pond 4 were able to gain a total of 

only 120 pounds. Thus, the fish in the treated 

pond gained 212 pounds more, though the same 

amounts of feed were offered and there were 

723 fewer catfish in the untreated pond. The 

catfish in Pond 3 gained only 38.5 percent in 

weight following treatment as compared to 

71.4 percent in Pond 1 and 138.7 percent in 

Pond 5. There was no apparent reason for 

their comparatively slow growth.

Ponds 5 and 6 were nearly identical in 

area, were stocked on the same day, were 

harvested only 9 days apart, and had almost 

identical rates of catfish survival. Hence, 

analysis of their production may afford the 

most clear-cut comparison of the benefits 

derived from treatment. For some unknown 

reason, the growth of catfish in Pond 5 prior 

to treatment was much poorer than that in 

Pond 6. At the time of August sampling, fish 

in the untreated pond were 32.3 percent 

heavier, the average weights of fish in the 

two ponds being 0.31 and 0.41 pounds, respectively. Following elimination of the 

scalefish in Pond 5, the fish grew at a much 

faster rate, and their average weight at harvest was 0.74 pounds as compared to an 

average of 0.76 pounds in Pond 6. Thus, the 

percentage difference in average weight was 

reduced from 32.3 to 2.7 percent. Furthermore, only 114 fish in the treated pond were 

too small for table use, while 235 of those in 

the untreated pond were undersize. Catfish in 

Pond 5 gained 696 pounds following treatment, 

while those in Pond 6 gained 568 pounds, for 

a difference of 128 pounds.

At the time of harvest, the local price for 

pond-reared catfish in the round was $0.50 

per pound, hence calculations of the value of 

the total weight of fish harvested whether of 

usable or unusable size are based on this 

figure. Antimycin costs are those of the first 

treatment only, because it reduced scalefish 

populations by nearly 99 percent even under 

the adverse water quality conditions which 

prevailed when the tests were made.

The greater amount of weight gained by 

catfish in treated ponds following treatment 

amounted to a total of 1,015 pounds of fish 

worth $507.50 (table 8). The cost of antimycin 

used in the first treatment was $145.79, leaving a net profit of $361.71. Thus, for each 

dollar invested in antimycin there was a 

minimum net return of $2.48.

Another rather easily estimated, but comparatively minor, benefit derived from treatment is the saving in the cost of food required 

to feed out undersize fish from both groups of 

ponds. Pond 3 yielded the smallest usable 

size fish, which had an average weight of 0.72 

pounds. The 421 undersize fish from the three 

treated ponds were underweight by 138 

pounds, while the 1,183 small fish from the 

two untreated ponds were underweight by 431 

pounds. Thus, if we assume that 1.8 pounds of 

food are required to produce each additional 

pound of catfish, and that food cost $125.00 

per ton, it would cost $15.52 to feed out fish 

from the former group of ponds, and $48.47 

to feed out those from the latter group, a 

difference of $32.95. The costs of labor, 

transportation, pumping of water and other 

factors attendent upon the greater length of 

time required to feed out the smaller fish

TABLE 8. Increase in total yield and market value of

channel catfish resulting from use of antimycin to reduce 

scalefish populations in three ponds

Pond

1......

3......

5......

TOTAL

Differential 

increase in 

yield (Ibs.) 1

675

212

128

1,015

Value of 

increased 

yield

$507.50

Cost of 

antimycin

cfecrt 1 Q

c > rj-i

32.59

$145.79

Met 

profit

OT > -I

$361.71

Derived by subtracting adjusted total weight gains in 

untreated ponds following date of treatment from those in 

treated ponds.
Burress and Luhning: Antimycin in Channel Catfish Ponds 11

from the untreated ponds would be difficult to 

compute, but they undoubtedly would be much 

greater than the cost of food.

Another interesting approach to evaluation 

of the economic loss caused by the presence 

of competing scalefishes is possible if we 

arbitrarily assume that the amount of food 

required to produce one pound of scalefish 

might have produced a pound of catfish instead. On this basis, the untreated ponds 

could have produced an additional 1,474 

pounds of catfish.

We recovered 1,155 fewer catfish from the 

untreated ponds, a significant factor which 

alone could spell the difference between 

operating the ponds at a profit or at a loss. 

Under the circumstances, we could not determine to what extent survival was reduced 

by scalefish predation on fingerling catfish, 

the vastly greater amount of competition of 

scalefish with catfish in untreated ponds, or 

factors of disease and accident which unaccountably operated to a much greater extent in the untreated ponds. Whatever the 

cause, the results were similar to those 

observed by Swingle (1959), who found that 

the presence of wild fishes in his experimental ponds reduced channel catfish production.

CONCLUSIONS

1. Nearly 99 percent of the scalefishes in 

three ponds used for channel catfish production were eliminated by an application 

of 5.0 p.p.b. of antimycin in two of the 

ponds and 7.5 p.p.b. in the third pond.

2. A followup treatment with 10 p.p.b. of 

antimycin further reduced the scalefish 

populations in all ponds and eliminated 

26.4 pounds per acre of tadpoles in Pond 

3.

3. The channel catfish were not harmed by 

the toxicant.

4. Two factors which prevented total eradication of the scalefish were: (a) pH of the 

water rose to high levels each afternoon

and caused rapid detoxification of the 

antimycin, and (b) average depth of the 

water in Pond 5 was only 3.5 feet, and full 

release of the toxicant was not achieved 

before the sand upon which it was formulated sank into the soft, muddy bottom.

5. The 5.0 and 7.5 p.p.b. concentrations of 

antimycin degraded to a level harmless to 

golden shiners and small green sunfish 

within 24 hours after application, and the 

10 p.p.b. concentration degraded within 

48 hours.

6. The untreated ponds, which produced an 

estimated 184,000 scalefish weighing 

nearly 1,474 pounds, yielded 1,155 fewer 

catfish than did the treated ponds.

7. If the second pair of ponds (Ponds 3 and 

4) in which stocking was done at widely 

different times is excluded from consideration, the average yield per acre of 

channel catfish from the treated ponds 

was greater than the adjusted yield per 

acre from untreated ponds by about 464 

fish weighing 558 pounds.

8. The increase in yield of channel catfish 

resulting from treatment amounted to 

1,015 pounds of fish worth $507.50, while 

the cost of Fintrol-5 for initial treatment 

was only $145.79 a net return of $2.48 

for each dollar invested in toxicant.

9. Selective removal of scalefishes from catfish ponds can be accomplished safely and 

economically through the use of antimycin.

REFERENCES

Berger, Bernard L., Robert E. Lennon, and James W. 

Hogan.

1969. Investigations in Fish Control: 26. 

Laboratory studies on antimycin A as a fish 

toxicant. U.S. Bureau of Sport Fisheries and 

Wildlife.

Bureau of Commercial Fisheries.

1966. Pond-reared catfish has good market potential. Commercial Fisheries Review, vol. 28, 

No. 6, p. 15-16.
12 Investigations in Fish Control 25: Bureau of Sport Fisheries and Wildlife

Meyer, Fred P. Swingle, H. S.

1965. The experimental use of Guthion® as a 1959. Experiments on growing fingerling channel 

selective fish eradicator. Transactions of catfish to marketable size in ponds. Proceedings 

the American Fisheries Society, vol. 94, of the 12th Annual Conference of Southeastern AsNo. 3, p. 203-209. sociation of Game and Fish Commissioners, Louisville, Kentucky, October 12-22, 1959. p. 63-72.
INVESTIGATIONS IN FISH CONTROL

26. Laboratory Studies on Antimycin A 

as a Fish Toxicant

By Bernard L. Berger, Chemist,

Robert E. Lennon, Fishery Biologist, and 

James W. Hogan, Chemist

United States Department of the Interior

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Washington, D.C. . February 1969
CONTENTS

Page

Abstract. .................................. 3

Methods and materials ......................... 3

Antimycin. .............................. 3

Stability ........................'..... 4

Detoxification ......................... 4

Bioassay procedures. ....................... 4

Column tests.......................... 4

Simulated field tests..................... 4

Water. ................................. 4

Temperature. ......................... 4

Hardness ............................ 4

PH................................. 5

Turbidity ............................ 5

Fish. .................................. 5

Eggs ............................... 5

Fry ................................ 5

Fingerlings. .......................... 6

Adults .............................. 6

Toxicity ................................ 6

Effective concentrations .................. 6

Effective contact time (EOT) ............... 7

Toxicity of injected antimycin. .............. 7

Results. ................................... 7

Bioassays with fingerlings. ................... 7

Temperature. ......................... 7

Water hardness ........................ 7

pH................................. 7

Turbidity ............................ 9

Effective contact time.................... 9

Sand-formulated toxicant.................. 9

Column tests.......................... 10

Bioassays with other life stages ................ 10

Fry ................................ 10

Juveniles and adults ..................... 13

Simulated field trials ....................... 15

Toxicity of injected antimycin. ................. 17

Stability of antimycin ....................... 17

Detoxification with potassium permanganate ........ 18

Discussion ................................. 19

Conclusions. ................................ 20

References ................................. 21
LABORATORY STUDIES ON ANTIMYCIN A AS A FISH TOXICANT

By Bernard L. Berger, Chemist, Robert E. Lennon, Fishery Biologist,

and James W. Hogan, Chemist 

Bureau of Sport Fisheries and Wildlife

Fish Control Laboratories 

La Crosse, Wisconsin and Warm Springs, Georgia

ABSTRACT. Liquid and sand formulations of antimycin A were tested 

in laboratory waters of various temperature, hardness, pH, and turbidity 

against 31 species of fresh-water fish of various sizes and life stages. 

Each formulation of toxicant was lethal under all water conditions to fish 

eggs, fry, fingerlings, and adult fish. Trouts are the most sensitive and 

catfishes the least sensitive. Of the 31 species, 24 succumb to 5 p.p.b. or 

less of the toxicant; only certain catfishes survive 25 p.p.b. The order of 

toxicity to various species of fish suggests that antimycin has possibilities 

for selective or partial control of certain unwanted fish. Although toxic to 

fish under ice, antimycin is more active in warm water than in cold. It is 

slightly more active in soft water than in hard; it is more active and persists far longer in water at pH 5 to 8 than at pH 9 or 10. It is active on fish 

in either clear and turbid waters, and it can be detoxified by potassium 

permanganate. The results contributed to registration of antimycin A in 

Fintrol-5 formulation as a fish toxicant.

Antimycin A in a formulation called Fintrol5 was approved and registered as a fish 

toxicant in the United States and Canada in 1966. 

Its early promise as a fishery tool was mentioned by Derse and Strong (1963) and Loeb 

(1964). It was patented as a piscicide by 

Strong and Derse in 1964. Concurrently Walker, 

Lennon, and Berger (1964) made preliminary 

observations on its toxicity to fish and other 

aquatic organisms.

The subsequent intensive testing against 

fish in the laboratory which contributed to 

approval of antimycin as a fishery tool is 

discussed in this report. The studies included 31 fishes of various life stages in 

waters of different qualities and tempera- 

:ures, indoor and outdoor bioassays, and liquid 

ind sand formulations of the toxicant. The 

objectives were to define lethal concentrations

for fish under a variety of conditions, to 

assess factors which contribute to degradation of the toxicant, and to find a substance 

which might be used to detoxify it.

Generous cooperation was afforded throughout the investigation by Wisconsin Alumni 

Research Foundation, owner of patents on 

antimycin; Ayerst Laboratories, New York, 

producer of antimycin; national fish hatcheries; and the Iowa, Minnesota, and Wisconsin 

Conservation Departments.

METHODS AND MATERIALS

ANTIMYCIN

The toxicant used in these investigations 

was supplied by the Wisconsin Alumni Research 

Foundation and by Ayerst Laboratories as

338-447 O - 69 - 3
Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

crystals of antimycin A, 96 to 98 percent 

pure, or in formulations of antimycin A coated 

on sand. Stock solutions were prepared by 

dissolving 10 mg. of crystals in 100 ml. of 

acetone or ethanol. Although the solutions 

remain stable for several months if kept in 

cool, dark storage, fresh stocks were made 

biweekly.

The sand formulation Fintrol-5 contains 

1 percent of antimycin A, 24 percent of Carbowax (polyethylene glycol 6000), and 75 percent 

of 40-mesh sand by weight. It is designed 

to release the toxicant into the water within 

a depth range of 0 to 5 feet as the particles 

sink to the bottom. Fintrol-15 is an experimental formulation, and the proportions of 

antimycin, Carbowax, and sand have not been 

released to us. It is supposed to release the 

toxicant within the first 15 feet of depth. 

Other formulations, such as a Fintrol-30 for 

greater depths, are under consideration.

Stability. The effect of heat on the stability 

of antimycin was investigated. Quantities of 

crystalline and sand-formulated toxicant were 

subjected to dry heat at 200° C. in a forcedair oven for 15, 30, 60, and 120 minutes. 

Samples of the heated materials were then 

tested against fingerling rainbow trout in 96- 

hour bioassays. Results were tabulated at 

0.25, 0.5, 1, 2, 3, 24, and 96 hours.

Detoxification. Potassium permanganate 

(KMnO4 ) was selected for preliminary testing 

as a detoxifier for antimycin in solution. Five 

to 500 p.p.b. of KMnO 4 were added to solutions which contained 5 p.p.b. of antimycin. 

Fingerling bluegills were placed in the solutions 6 or 24 hours later and their responses 

were noted at 6, 12, 24, 48, 72, and 96 hours 

to detect the extent and rate of detoxification.

BIO ASSAY PROCEDURES

Static bioassays of antimycin were conducted as described by Lennon and Walker 

(1964) and Walker, Lennon, andBerger (1964). 

Some special tests required innovations.

Column tests. A plexiglass column 8 feet 

high and 1 foot in diameter, with walls onefourth-inch thick, was set up to determine

the uniformity and strength of antimycin released by the sand formulation at selected 

depths. The column was filled with reconstituted water at 12° C., and quantities of 

Fintrol were applied at the surface and allowed 

to sink to the bottom. Water from various 

depths was sampled by siphon and analyzed 

for the toxicant by 96-hour bioassays with 

rainbow trout and goldfish.

Simulated field tests. The availability of 

greater quantities of antimycin in the spring 

of 1966 enabled us to initiate trials against 

communities of small and large fish in 0.01- 

acre concrete pools. Each pool contained 

43,000 liters of pond water at a 3.5-foot 

depth or 24,668 liters at a 2-foot depth. 

Selected wild and hatchery-reared fish were 

stocked in pools 3 to 7 days before treatment 

with antimycin. Stocking densities ranged from 

less than 100 to 2,000 pounds per acre. Dead 

fish were removed daily, and the ponds were 

drained after each experiment to obtain full 

tallies of fish.

A series of warm-weather tests was made 

using 12 species of fish at densities from 

1,000 to 2,000 pounds per acre. The concentrations of antimycin applied were 1, 2, 3, 4, 

5, 10, and 20 p.p.b. at 11° to 21° C.

Juvenile and adult fish of four species 

were used in the cold-weather tests in the 

pools. Tests were made using both clear and 

turbid water, at 3.4° to 5.5° C.

WATER

Most bioassays were run in reconstituted 

deionized water (Lennon and Walker, 1964) 

but well water or pond water was used in 

some of the outdoor tests.

Temperature. Heated or chilled water 

baths were used as needed to control the 

temperatures of indoor bioassays at 2° to 

27° C. Bioassays in outdoor pools were run 

at ambient temperatures; some under 6 inches 

of ice and others at temperatures up to 30° C.

Hardness. Total hardness of bioassay 

waters ranged from 20 to 400 p.p.m. Most 

tests took place in our standard, reconstituted
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant

water, which has a total hardness of 40 

p.p.m.

pH. The range of pH in bioassay media 

was 5 to 10. The desired levels were attained 

by adding buffers to reconstituted water (table 

1). Because the contrived levels tended to 

regress toward neutral, they were restored 

each 24 hours by adding small amounts of 

the buffer reagents. Close monitoring of control vessels which contained fish but no 

toxicant indicated the extent of change and 

the amount of readjustment necessary.

at a depth of about 2 feet. Four pools had 

2 inches of clay-loam on the bottom and a 

Secchi disk reading of 6 inches. Four pools 

had no soil on the bottom, and the water 

remained clear. Three turbid pools were 

treated with 5.0, 7.5, and 10.0 p.p.b. of antimycin respectively; the fourth served as a 

control. Similar concentrations of antimycin 

were applied in three clear pools, and the 

fourth pool served as a control. Observations on mortalities of fish were made daily 

up to 18 days at which time we drained the 

pools and made a final assessment.

TABLE 1. Buffer reagents added to reconstituted water 

to yield 15 liters of bioassay media of various pH 

levels

pH

5 +0.1....

6 +0.1....

7 +0.1....

8 +0.1....

9 +0.1....

10 +0.1....

Volume of buffer reagent 1 (ml. )

l.ON 

NaOH

10

2

10

25

8

20

0.1M 

KHC8 H4 04

510

--

--

--

--

--

l.OM 

KH2 P04

90

30

30

--

--

l.OM 

H3B03

__

--

--

--

30

21

1 NaOH = Sodium hydroxide.

KHCgH,^ = Potassium acid phthalate. 

KH2 P04 = Potassium phosphate (monobasic). 

H3B03 = Boric acid.

Turbidity. The activity of antimycin in 

the presence of suspended clay was checked 

in 96-hour bioassays with rainbow trout. 

Weighed portions of the clay were stirred 

into the bioassay media to produce turbidities 

of 1,000 and 5,000 p.p.m. (Secchi disk readings of 10 and 4 inches). The concentrations 

of antimycin ranged from 0.04 to 0.30 p.p.b. 

and the temperature was 12° C. All vessels 

were stirred for 30 seconds during each hour 

of the first 6 hours of the bioassay and at 

each 24 hours thereafter to keep the clay in 

suspension.

The performance of Fintrol-5 was tested 

against brown trout, goldfish, carp, bluegill, 

and largemouth bass in turbid water in outdoor, concrete pools at 3.4° to 5.5° C. Each 

pool contained about 25,000 liters of water

FISH

Most of the fish were obtained from National 

and State fish hatcheries, but wild specimens 

were used in certain tests (table 2). All were 

held under conditions of quarantine and pretest 

evaluation as described by Lennon and Walker 

(1964).

Eggs. We studied the effects of antimycin 

on fertilized eggs of rainbow trout, northern 

pike, goldfish, carp, white sucker, and channel 

catfish. At first, groups of eggs of certain 

ages, green and eyed, were counted and placed 

in petri dishes. The dishevs were then immersed in solutions of antimycin for certain 

lengths of time. Later, aluminum wire or 

saran mesh baskets, approximately 2 by 2 by 

2.5 inches were used. Containers of this size 

were capable of holding 100 rainbow trout eggs.

The baskets of eggs were either exposed for 

specific periods or remained in the solutions 

of antimycin until the eggs perished or hatched. 

Those removed after short exposures were 

rinsed and placed in hatching jars, troughs, 

or Heath egg incubators. Groups of control 

eggs were exposed to solutions of the solvent 

in water and otherwise handled similarly.

Fry. Bowfin 21 to 56 days old and rainbow 

trout 3 to 60 days old were exposed to antimycin in 1- or 5-gallon bioassay vessels. 

Channel catfish less than 1 day old and largemouth bass 1 to 2 days old were placed in 

petri dishes containing various concentrations 

of toxicant. Following exposure, the fish were 

removed, rinsed, and placed in fresh water 

for observation.
Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 2. List of 31 fishes exposed to antimycin

Species

Life stage

Fry Fingerling Mult J

Source

Hatchery Wild

Shortnose gar, Lepisosteus platostomus-............

Bowfin, Amis calva.................................

Rainbow trout, Salmo gairdneri...................... X

Brown trout, Salmo trutta..........................

Brook trout, Salvelinus fontinalis.................

Lake trout, Salvelinus namaycush...................

Northern pike, Esox lucius.......................... X

Goldfish, Carassjus auratus......................... X

Northern redbelly dace, Chrosomus eos..............

Carp, Cyprinus carpio..............................

Fathead minnow, Pimephales promelas................

Quillback, Carpiodes cyprinus......................

White sucker, Catostomus commersoni................. X

Bigmouth buffalo, Ictiobus cyprinellus.............

Spotted sucker, Minytrema melanops.................

White catfish, Ictalurus eatus.....................

Black bullhead,. Ictalurus melas....................

Channel catfish, Ictalurus punctatus................ X

Flathead catfish, Pylodictis olivaris..............

Brook stickleback, Eucalia inconstans.'.............

Green sunfish, Lepomis cyanellus...................

Pumpkinseed, Lepomis gibbosus......................

Bluegill, Lepomis macrochirus......................

Longear sunfish, Lepomis megalotis.................

Redear sunfish, Lepomis microlophus................

Smallmouth bass, Micropterus dolomieui.............

Largemouth bass, Micropterus salmoides.............

Black crappie, Pomoxis nigromaculatus..............

Yellow perch, Perca flavescens.....................

Walleye, Stizostedion v. vitreum...................

Freshwater drum, Aplodinotus grunniens.............

1 May include juvenile as well as adult fish.

Fingerlings. Routine bioassays were made 

with small fingerlings which usually range 

from 0.5 to 2.0 grams each. At least 10 fish 

of each species were used with each concentration of chemical and in each control. The 

loading in 5-gallon jars containing 15 liters 

of test solution or in 1-gallon jars containing 

2.5 liters of solution was 1 gram or less of 

fish per liter. Observations on the responses 

of the fish to the toxicant were made at 3, 6, 

24, 48, 72, and 96 hours.

Adults. Since it is possible that the responses of adult fish to a toxicant may differ 

from those of younger fish, we exposed adults 

of 17 species to antimycin in 500-gallon concrete tanks, in 1,000-gallon vinyl tanks, or 

in 0.01-acre concrete pools. Most of them 

were obtained from the wild, and many of the 

tests were of the community type, involving 

two or more species at a time. All specimens 

were held in quarantine for several days to

determine whether they were in satisfactory 

condition for bioassays. They were stocked 

in the pools 3 to 7 days before exposure to 

antimycin.

TOXICITY

Effective concentrations. Results of most 

of the bioassays of antimycin with fish are 

expressed as 24-, 48-, 72-, and 96-hour 

EC0 , EC50 , or EC 100 , that is, the concentrations of toxicant in parts per billion which 

kill 0, 50, or 100 percent of the fish within 

24, 48, 72, or 96 hours. In deriving the expressions, the responses observed in early 

tests were subjected to probit analyses to estimate the effective concentrations (Litchfield 

and Wilcoxon, 1949). The estimates were 

corrected or confirmed by subsequent bioassays with replications. Confidence intervals 

(C.I.) for EC 50 's are given where possible.
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant

Effective contact time (ECT). Antimycin 

kills fish slowly, and we suspect that specimens have had lethal exposures well before 

they showed signs of distress or death. Moreover, EC 50 *s and ECioo fs at 24 through 96 

hours in static bioassays do not pinpoint the 

minimum exposures necessary to kill fish. 

Nine species of fish were used in trials to 

define the durations of minimum lethal exposures in given concentrations of antimycin. 

Following the exposures at 12° C., the fish 

were transferred to fresh water and observed 

for at least 96 hours.

Toxicity of injected antimycin. Six- to 

12-inch rainbow trout, carp, and black bullheads were injected intraperitoneally with 

ethanol solutions of antimycin to determine 

toxicities which might possibly be compared 

with the immersional toxicities. The amounts 

of toxicant in milligrams were selected according to the body weights of the fish in 

kilograms. The injected volumes ranged from 

0.2 to 1 ml. per fish. Control fish were given 

injections of ethanol in water, with the quantity of solvent equaling the greatest amounts 

used to dissolve the antimycin. The fish 

were held at 12° C. for 5 days, except that 

dead fish were discarded daily.

RESULTS

BIOASSAYS WITH FINGERLINGS

The majority of bioassays of antimycin in 

the laboratory in waters of various qualities 

involved small fingerlings. The responses 

of these fish, therefore, serve as standards 

by which the responses of other life stages 

are evaluated.

Temperature. In general, fish are more 

susceptible to antimycin at warmer temperatures (table 3). There were twofold to fivefold 

differences between ECHO'S at 7° and 22° C.

Less than 1 p.p.b. of toxicant killed all 

individuals of 14 species at one or more 

temperatures. The more sensitive fish are 

rainbow trout, brown trout, brook trout, lake 

trout, and walleye. The often undesirable

carp, green sunfish, and pumpkinseed are 

also among the more sensitive fish. In contrast, the catfishes are relatively resistant. 

At temperatures from 22° to 7° C., 8 to 22 

p.p.b. of antimycin are needed to kill channel 

catfish and 50 to 120 p.p.b. to kill black 

bullheads.

Water hardness. Tests of antimycin against 

rainbow trout in waters of 20, 48, 90, 180, 360, 

and 400 p.p.m. total hardness demonstrated 

that the toxicant is slightly less effective in 

harder water. For example, 0.06 p.p.b. of the 

antibiotic killed all fish at 20 p.p.m. total 

hardness but none at 360 p.p.m.; and 0.08 

p.p.b. killed less than half the fish at 360 

p.p.m. total hardness.

In later tests, the 96-hour ECHO'S for rainbow trout, goldfish, and bluegill at 20 and 

400 p.p.m. total hardness confirmed that 

antimycin is a little less effective in hard 

water.

pH. The effectiveness of antimycin against 

fish is influenced substantially by the pH of 

the medium. Preliminary 96-hour bioassays 

were conducted with goldfish, at pH 5 to 10. 

The results indicated that ECHO'S increased 

three fold between pH 5 and 8; six fold between pH 8 and 9; and fourteen fold between 

pH 9 and 10. More definitive experiments 

with goldfish in 15-liter solutions of toxicant 

at pH 5 to 10 at 12° gave 96-hour EC10o's of 

0.20 p.p.b. at pH 5; 1.10 p.p.b. at pH 8; and 

60 p.p.b. at pH 10 (table 4 and fig. 1).

Subsequently we attempted to conduct experiments with rainbow trout at various levels of 

pH, but the species were intolerant to the 

buffers at pH 6 and 10. The results at pH 7, 

8, and 9 at 12° indicate that the toxicity of 

antimycin is reduced at higher pH levels. 

The 96-hour EC 100 at pH 7 was 0.04 p.p.b., 

whereas it was 0.18 at pH 9.

A similar trend was evident in tests with 

carp at pH 7 through 10. The 96-hour ECHO'S 

of antimycin ranged from 0.6 p.p.b. at pH 7 

to 4.0 p.p.b. at pH 9. At pH 10, there was a 

sharp increase in the EC 100 to 20.0 p.p.b.
8 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 3. Effective concentrations of antimycin on 22 species of fish in 96-hour exposures at selected temperatures

Species

Do

Do

Do..............

Do

Do. .............

Do. .............

Do. .............

Northern redbelly dace 

Do

Do

Do. .............

Do..............

Do..............

Do..............

Do..............

Do

Do..............

Do..............

Do..............

Do..............

Do

Do..............

Brook stickleback. . . . 

Do..............

Do..............

Do..............

Do..............

Do..............

Do..............

Do..............

Do..............

Do..............

Do..............

Do

Yellow perch

Do..............

Walleye..............

Do..............

Do. .............

Do..............

Number 

of 

fish

120

180 

180 

204

180 

148

60

72 

176 

176 

168

192 

200 

192 

216

120 

120 

60 

60

120 

240 

120 

96

120 

120 

120 

120

120 

216 

156 

120

120 

120 

180 

240

120 

180 

120 

120

120 

180 

216 

120

120 

180 

120 

120

120 

120 

180 

180

120 

120

120 

120 

120

120 

120 

120

180 

204 

204 

208

204 

120

120 

60 

60 

60

Average size

Length 

( inches )

1.5 

3.3

1.2

1.9 

1.9 

1.9 

2.5

2.1 

2.1 

2.1 

2.1

2.3 

2.2 

2.2 

2.4

2.1 

2.1 

2.1 

2.1

1.4 

1.4 

1.4 

1.3

1.8

^ 1.8

1.8

2.0

1.8

1.3

1.3 

1.3

1.6 

1.6

1.6

2.0 

2.0

1.5 

1.5

2.9 

2.9 

2.9 

2.9

Weight 

(grams)

0.8

1.5 

1.5 

1.6

1.5 

1.5

4.0

1.4 

0.8 

2.0 

1.9

2.3

2.0 

2.0 

0.4

1.1 

1.1 

1.1 

2.4

2.0 

2,0 

2.0 

2.0

0.7 

1.6 

0.7 

1.7

2.4 

2.1 

2.1 

2.3

1.9 

1.9 

1.9 

1.9

1.1 

1.1 

1.1 

1.1

0.7 

0.7 

0.7 

0.6

1.3 

1.4

1.4 

1.3

2.5 

2.5 

1.3 

0.8

1.0 

1.3

0.5 

0.5 

0.5

0.8 

0.8 

0.8

1.2 

0.5 

2.0 

0.5

0.7 

0.7

3.3 

3.3 

3.3 

3.3

(°c.)

12

7 

12 

17

12

17

12

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

7 

12 

17 

22

12 

17

12 

17 

22

12 

17 

22

7 

12 

17 

22

12

17

7 

12 

17 

22

Concentrations expressed in p.p.b.

EC0

0.10

0.06 

0.02 

0.01

0.02 

0.01

0.06

0.40 

0.10 

0.08 

<0.10

0.20 

0.20 

0.10 

0.10

0.10 

<0.10 

0.04 

0.04

0.20 

0.10 

0.10 

0.04

<0.20 

0.08 

0.06 

0.04

40.00 

40.00 

20.00 

<20.00

6.00 

4.00 

2.00 

4.00

0.40 

0.10 

0.10 

<0.06

0.20 

0.10 

0.08 

0.06

0.10 

0.08 

0.06 

0.04

0.20 

0.08 

0.06 

0.04

0.05 

0.05

0.01 

0.02 

0.01

0.08 

0.06 

0.04

0.06 

0.02 

0.04 

0.02

0.04 

>0.01

0.08 

0.04 

0.02 

0.01

EC 100

1.00

0.20 

0.60 

0.04

0.03 

0.04

0.10

>0.60 

0.40 

0.20 

0.14

2.00 

1.00 

0.40 

0.40

>0.50 

0.60 

0.30 

0.10

0.80 

0.60 

0.40 

0.20

0.40 

0.40 

0.12 

0.08

120.00 

100.00 

60.00 

50.00

22.00 

16.00 

>10.00 

8.00

>0.60 

0.40 

0.25 

0.08

0.80 

0.40 

0,25 

0.20

0.40 

0.20 

0.20 

0.10

0.60 

0.20 

0.15 

0.10

0.20 

0.25

0.10 

0.08 

0.12

0.20 

0.20 

0.20

0.20 

0.10 

0.06 

0.04

0.08 

0.03

0.25 

0.15 

0.06 

0.04

EC5Q and 95 -percent 

C.I.

0.48

0.08 

0.04 

0.03

0.06 

0.03

0.07

0.55 

0.26 

0.14 

0.11

1.00 

0.50 

0.35 

0.20

0.52 

0.18 

0.09 

0.09

0.43 

0.35 

0.25 

0.12

0.20 

0.21 

0.09 

0.06

88.00 

45.00 

32.00 

21.00

10.50 

9.00 

7.40 

5.20

0.55 

0.21 

0.16 

0.04

0.50 

0.20 

0.15 

0.11

0.24 

0.14 

0.09 

0.05

0.50 

0.14 

0.07 

0.06

0.08 

0.09

0.04 

0.04 

0.06

0.14 

0.10 

0.09

0.12 

0.05 

0.04 

0.03

0.04 

0.02

0.14 

0.07

0.02

0.36- 0.65

0.07- 0.09 

0.03- 0.04 

0.02- 0.04

0.06- 0.07 

0.03- 0.04

0.06- 0.08

0.50- 0.57 

0.23- 0.30 

0.12- 0.34 

0.08- 0.16

0.83- 1.20 

0.42- 0.60 

0.25- 0.49 

0.16- 0.25

0.37- 0.73 

0.15- 0.21 

0.07- 0.12 

0.08- 0.11

0.36- 0.51 

0.30- 0.40 

0.21- 0.30 

0.09- 0.16

0.17- 0.23 

0.16- 0.28 

0.08- 0.10 

0.05- 0.08

73.00-105.00 

38.80- 52.20 

27.60- 37.20 

15.50- 28.00

9.50- 11.70 

7.30- 11.60 

6.60- 8.40 

4.90- 5.60

0.52- 0.58 

0.18- 0.24 

0.14- 0.18 

0.04- 0.05

0.43- 0.59 

0.15- 0.24 

0.11- 0.18 

0.10- 0.12

0.20- 0.29 

0.12- 0.17 

0.08- 0.10 

0.05- 0.07

0.45- 0.56 

0.11- 0.17 

0.06- 0.14 

0.05- 0.07

0.07- 0.11 

0.08- 0.11

0.03- 0.05 

0.03- 0.04 

0.04- 0.07

0.09- 0.20 

0.07- 0.10 

0,07- 0.11

0.11- 0.14 

0.04- 0.06 

0.04- 0.05 

0.03- 0.04

0.04- 0.05 

0.02- 0.03

0.12- 0.17 

0.06- 0.09

0.01- 0.03
TABLE 4. Concentrations of antimycin in p.p.b. which 

caused 0- and 100-percent mortality in fingerling 

rainbow trout, carp, and goldfish at pH levels 5 

through 10 at 12° G.

Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 

100

pH

Rainbow trout 

7 +0.1..........

8 +0.1..........

9 +0.1..........

Carp 

7 +n i

8 +0.1..........

9 +0.1..........

10 +0.1..........

Goldfish

5 +0.1..........

6 +0.1..........

7 +0.1..........

8 +0.1..........

Q j_n -i

10 +0.1..........

Number 

offish

100 

100 

100

100 

100 

100 

100

110 

70 

130 

70 

70 

140

96 -hour

EC0

0.01 

0.03 

0.06

0.10 

0.10 

1.60 

9.40

0.10 

0.10 

0.09 

0.30 

2.00 

20.00

ECioo

0.04 

0.07 

0.18

0.60 

1.00 

4.00 

20.00

0.20 

0.30 

0.40 

1.10 

6.00 

60.00

Turbidity. The presence of 1,000 and 5,000 

p.p.m. of clay in suspension influenced the 

toxicity of antimycin to 2.5-inch rainbow 

trout at 12° C. The medium with 1,000 p.p.m. 

of clay turbidity was only slightly less toxic 

than the control to the fish at 24, 48, and 96 

hours. The high turbidity medium had 24-, 

48-, and 96-hour EC50 's of 0.40, 0.14, and 0.10 

P.P.b., while those of the control were 0.16, 

0.10, and 0.05 p.p.b.

Some additional observations on the performance of antimycin in turbid water are 

given under Simulated Field Trials.

Effective contact time. Only brief exposures to antimycin are needed to kill fish 

(table 5). At 10p.p.b. of toxicant, the ECTioo's 

are 1 hour for green sunfish and bluegill, 

and 4 hours for carp, longear sunfish, and 

black crappie. In contrast, black bullheads 

require a minimum exposure of 3 to 4 hours 

to a concentration of 500 p.p.b. fora complete

10

i.o

0.1

.01

10

PH

Figure 1. Relation between various concentrations of 

antimycin and levels of pH necessary to produce 

ECHO'S for selected fishes at 12° C.

kill. These data are especially pertinent if 

the toxicant were to be used in the reclamation of streams or in situations where high 

pH contributes to rapid degradation.

Sand-formulated toxicant. Preparations of 

antimycin coated on sand were obtained rather 

late in the experimental program. Fintrol-5 

and Fintrol-15 were compared with crystalline 

antimycin in acetone solutions for effectiveness against fingerling rainbow trout and 

carp.

Fintrol-5 contains 10 mg. of antimycin per 

gram of formulation. Its 96-hour EC 50 's for 

rainbow trout and carp at 12° C. were 0.04 

and 0.20 p.p.b. respectively. By comparison, 

the EC 50 's of acetone-antimycin under the 

same circumstances were rainbow trout 0.03 

p.p.b. and carp 0.20 p.p.b.
10 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 5. Effective contact time (EOT) of antimycin against selected fishes at 12°C in standard reconstituted water 1

Species

Do................

Do................

Dn

Do. ...............

Do................

Do................

Do. ...............

Do. ...............

Do. ...............

Do................

Do. ...............

Do................

Do. ...............

Do. ...............

Do................

Do. ...............

Number 

Of "fish

50

80 

80 

40 

80

80 

80

80 

80 

80

80 

80 

80

80 

80 

80 

80

60 

60

35 

35 

35

80 

80 

80

Average size

Length 

(in.)

1.5

1.6 

1.6 

1.6 

1.6

1.9 

1.9

2.2 

2.2 

2.2

1.4 

1.4 

1.4

1.7 

1.7 

1.7 

1.7

3.1 

3.1

3.6 

3.6 

3.6

2.2 

2.2 

2.2

Weight 

(g.)

1.0

0.9 

0.9 

0.9 

0.9

1.1 

1.1

2.2 

2.2 

2.2

1.0 

1.0 

1.0

1.1 

1.1 

1.1 

1.1

7.8 

7.8

7.8 

7.8 

7.8

1.6 

1.6 

1.6

Antimycin 

(p.p.b.)

50

1 

10 

50 

100

1 

10

250 

500 

1,000

1 

10 

100

1

10 

50 

100

10 

100

1 

10 

100

1

10 

100

ECTQ

< 15 min.

< 2 hrs .

30-60 min. 

< 7.5 min. 

< 4 min.

4 hrs. 

3.0-7.5 min.

<4 hrs. 

30-60 min. 

15-30 min.

< 6 hrs . 

< 15 min. 

< 1 min.

> 15 min. 

>7.5 min. 

1-2 min. 

1-2 min.

15-30 min. 

1-2 min.

30-60 min. 

4-7.5 min. 

1-2 min.

30 min. 

< 30 min. 

< 15 min.

EGTso

15-30 min.

2-4 hrs. 

1-2 hrs. 

7.5-15 min. 

4-7.5 min.

7.5 hrs. 

30-45 min.

> 8 hrs. 

1-2 hrs. 

1-2 hrs.

>6.5 hrs. 

15 min. 

1.5 min.

15-30 min. 

7.5-15 min. 

2-4 min. 

2-4 min.

1-2 hrs. 

2-7.5 min.

> 4 hrs. 

0.5-2 hrs. 

7.5-15 min.

1.0-1.5 hrs. 

30 min. 

< 15 min.

ECT100

30-60 min.

> 4 hrs. 

2-4 hrs. 

15-30 min. 

7.5-15 min.

12-14 hrs. 

2 hrs.

> 8 hrs. 

3-4 hrs. 

2-4 hrs.

22 hrs. 

30-60 min. 

> 4 min.

30-60 min. 

15-60 min. 

4-7.5 min. 

4-7.5 min.

2-4 hrs. 

7.5-15 min.

> 4 hrs. 

2-4 hrs. 

15-30 min.

>1.5 hrs. 

1-2 hrs. 

< 15 min.

All test animals were observed for a minimum of 96 hours after transfer to fresh water.

Fintrol-15 has 26 mg. of antimycin per 

gram of formulation. Its EC 50's at 96 hours 

of 0.07 p.p.b. for rainbow trout and 0.15 p.p.b. 

for carp compare very favorably with those 

of acetone-antimycin or Fintrol-5 solutions.

Column tests. The release of antimycin 

from Fintrol-5 is apparently uniform but not 

complete within the first 5 feet of depth in the 

8-foot plexiglass column. Samples siphoned 

at depths of 1 to 5 feet were toxic to all 

rainbow trout within 24 hours. Four of 16 

trout survived in a sample taken at 6 feet, 

and all trout lived in a sample at 7 feet. 

There is obviously some further release of 

toxicant from sand lying on the bottom, because a sample of water drawn at 8 feet 

killed all trout.

We were unable to test the release of 

antimycin from Fintrol-15 at depths greater 

than 8 feet. The bioassays of samples taken 

at 1 through 8 feet in the column demonstrated a uniform release of toxicant.

Some of the first samples of Fintrol had a 

tendency to lie on the surface film when 

sprinkled lightly at the top of the column. 

This was corrected by the manufacturer, 

and later samples penetrated the film, sank 

readily to the bottom, and gave a good dispersion of the toxicant.

BIOASSAYS WITH OTHER LIFE STAGES

Eggs. Antimycin is toxic to fertilized eggs 

of rainbow trout, northern pike, goldfish, 

carp, white sucker, and channel catfish. Recently, Valentine (1966) demonstrated that 

the antibiotic also kills fertilized eggs of 

zebra fish (Brachydanio rerio).

The first experiments included newly fertilized, water-hardened eggs of rainbow trout 

which had developed to about the 32-cell 

stage during the first 24 hours. Groups of 

100 eggs were exposed to 1 and 100 p.p.b. 

of antimycin for 30, 60, and 120 minutes
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 11

and then transferred into a Heath egg incubator. Control groups were handled similarly but not exposed to the toxicant. Embryogeny was compared by removing several 

eggs per day from treated and untreated groups. 

After 2 weeks, the eggs were sampled each 

2 to 4 days. The samples were fixed in 5- 

percent formalin in 1-percent saline. Chorions 

were removed, and the embryos were stained 

in Harris hematoxylin and examined.

Within 24 hours, the eggs exposed to 100 

p.p.b. of toxicant for 120 minutes ceased development at about the 64-cell stage. Among 

control eggs, the blastoderms were well developed. Coagulation of protein was evident 

in dead eggs on the fourth day after treatment, and all eggs in the group were opaque 

by the seventh day.

The eggs exposed for only 60 minutes to 

100 p.p.b. of toxicant developed somewhat 

further. Cell division in some continued for 

2 days. Protein coagulation in dead eggs continued from the fourth to the llth day.

Some eggs exposed to 100 p.p.b. of antimycin 

for 30 minutes showed development comparable 

to that of controls for 8 to 13 days after treatment. In others, development terminated at 

the blastoderm stage. The greater number 

of opaque eggs appeared after 7 days. Microscopic examination of the embryos revealed 

no gross morphological or anatomical 

changes attributable to the toxicant.

The eggs exposed to 1 p.p.b. of toxicant 

and control eggs were "eyed" 15 days after 

fertilization, and they hatched 16 days later. 

There was no significant difference in the 

hatching success of the treated and control 

groups.

Long-term exposures to small concentrations of antimycin effected eggs of rainbow 

trout. Acetone solutions or sand formulations of toxicant were added to 1-gallon jars 

which contained approximately 100 fertilized 

eggs each. The medium was reconstituted 

water at 12° C.,pH 7.2 to 7.6, and total hardness of 40 p.p.m. The eggs remained in the 

jars throughout incubation and swim-up.

The eggs became eyed after 15 days and 

hatched at 29 days, and the sac fry reached 

swim-up stage at 42 days. Observations continued through 67 days, at which time the 

control fish were of routine bioassay size, 

that is, approximately 500 per pound. None 

of the eggs exposed to 0.5 p.p.b. or more of 

acetone-antimycin survived to the eyed stage 

(table 6). Most embryos from eggs exposed to 

0.1 p.p.b. lived through the eyed and hatching 

stages, but mortalities were heavy at swimup, as the fry seemed unable to take food. 

Only 7 percent survived through 67 days. All 

fry from eggs exposed to the sand formulation 

at 0.1 to 1.0 p.p.b. of antimycin perished 

within 42 days. Eggs treated with acetoneantimycin solutions survived through 67 days. 

The control group had a survival of 55 percent at 67 days. Bioassays with fingerling 

rainbow trout in eggless control solutions 

of the toxicant demonstrated that both formulations had degraded within the first 14 days 

of the experiment.

In another series of tests at 12°, the eggs 

of northern pike exhibited greater sensitivity 

to antimycin than those of rainbow trou): and 

white sucker (table 7). The green eggs of 

trout were more sensitive than eyed eggs.

The eggs of goldfish and carp also proved 

susceptible to antimycin. All goldfish eggs 

were killed by 2-hour exposures to 7.5 and 

10 p.p.b. of toxicant, and only 1 percent 

survived 5 p.p.b. (table 8). All eggs of goldfish and carp died when exposed to 2.5 p.p.b.

TABLE 6. Mortality of rainbow trout eggs incubated in 

solutions of antimycin at 12° C.

Antimycin

In acetone:

0.10 p.p.b.

0.25 p.p.b.

0.50 p.p.b.

0.75 p.p.b.

1.00 p.p.b.

On sand:

0.10 p.p.b.

0.25 p.p.b.

0.50 p.p.b.

0.75 p.p.b.

1.00 p.p.b.

Number 

of 

eggs

107

125

116

105

111

97

90

98

88

101

105

Percent mortality at 

3 

days

9

10

9

10

12

6

6

5

5

5

4

6 

days

13

36

100

100

100

7

8

82

76

100

6

15 

days1

30

91

~

--

9

18

100

100

10

29 

days2

37

93

--

--

20

27

--

35

42 

days3

87

96

--

-_

100

100

--

40

67 

days4

93

100

--

-_

~

--

--

--

45

- Eggs eyed.

2 Eggs hatched.

3 Swim-up.

* Fingerling stage.

338-447 O - 69 - 4
12 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 7. Survival of fish eggs after exposure to aqueous 

solutions of antimyein in acetone at 12° C.

[The postexposure period of observation was 3 to 30 days]

Species 

and age of

eggs

Rainbow trout

(24 hours after

fertilization)

Rainbow trout

(3 days, before

hatching)

Northern pike

(24 hours after

fertilization) 1

White sucker

(8 days before

hatching)

Number 

of

eggs

300

300

300

300

300

600

600

600

450

450

450

Length 

of

exposure

(min.)

30

60

30

60

120

30

60

120

30

60

120

Percentage

survival 

at concentrations

(in p.p.b.)

1.0

100

100

100

100

100

100

80

25

100

100

100

10.0

20

0

100

100

0

100

50

0

100

100

0

100.0

0

0

0

0

0

0

0

0

0

0

0

Not feasible to hold 30 days.

TABLE 8. Survival of 24-hour-old eggs of goldfish 

after 2-hour exposure to antinycin at 17° C.

Antimyein

1.0 p.p.b...........

2.5 p.p.b...........

5.0 p.p.b...........

7.5 p.p.b...........

10.0 p.p.b...........

Number 

of eggs

100

100

100

100

inn

100

Percentage 

hatch

irt

15

1

0

0

61

or more throughout the 7-day incubation period. 

Further experiments at 19° to 23° showed 

that 10 p.p.b. of antimyein which were allowed 

to degrade for 96 hours were no longer toxic 

to goldfish eggs. However, a solution which 

originally contained 20 p.p.b. of toxicant killed 

70 percent of exposed goldfish eggs within 

96 hours.

The eggs of channel catfish can be killed 

with antimyein (table 9), but they are substantially more resistant than those of rainbow trout, northern pike, goldfish, carp, and 

white sucker. Fertilized eggs about 24 hours 

old were placed in small baskets of saran 

mesh. Some were exposed for 2 hours to 

selected concentrations of antimyein; others 

were exposed to the toxicant throughout the 

6-day incubation period. The solutions of 

toxicant were aerated, constantly agitated, 

and temperatures ranged between 25° and 

28.5° C. At 100 p.p.b. or less, over 90 percent of the eggs survived 2-hour exposures.

TABLE 9. Survival of eggs of channel catfish 

following brief and prolonged exposures to 

antinycin at 25° to 28.5° C.

Antimyein

Two-hour exposure: 

20 p. p. b. ..........

40 p. p. b. ..........

60 p.p.b...........

80 p.p.b. ..........

100 p.p.b...........

250 p.p.b. ..........

500 p. p. b. ..........

750 p.p.b. ..........

1,000 p.p.b. ..........

Six- day exposures : 

10.0 p.p.b. ........

12.5 p.p.b.........

15.0 p.p.b.........

17.5 p.p.b.........

20.0 p.p.b. ........

25.0 p.p.b.........

27.5 p.p.b. ........

30.0 p.p.b.........

40.0 p.p.b. ........

50.0 p.p.b. ........

Number 

of eggs

100

100

100

100

200

100

100

100

100

90O

30

 3f)

30

 an

60

30

30

30

30

30

60

Percentage 

hatch

93

96

93

100

97

19

0

0

0

95

93

96

83

90

95

26

0

0

0

0

96

In contrast, all eggs succumbed to prolonged exposures to 27.5 p.p.b. or more 

of antimyein.

Fry. Bowfin, rainbow trout, channel catfish, and largemouth bass fry were subjected 

to antimyein. Because their ages differed, we 

cannot say which species are the more sensitive at a given age.

Bowfin exhibited increasing resistance to 

the toxicant with increasing age. The 96-hour 

ECso's were 0.13 p.p.b. at 3 weeks of age, 

0.24 p.p.b. at 6 weeks, and 0.35 p.p.b. at 8 

weeks. A comparable trial with 15 p.p.b. 

killed 12 adult fish.

The responses of rainbow trout sac fry 

and advanced fry to antimyein were approximately the same as those of fingerlings 

(table 10). The 96-hour EC5o's of 5-t 12-, 

and 18-day-old sac fry at 12° C. were 0.04, 

0.03, and 0.05 p.p.b. respectively, whereas 

the EC so for 44-day-old advanced fry and 

60-day-old fingerlings was 0.04 p.p.b.

The fry of channel catfish, only a few hours 

old, were more sensitive than the eggs to the 

toxicant. On the other hand, they were more
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 13

TABLE 10. Toxicity of antimycin in p.p.b. to sac and advanced fry of rainbow trout

at 12U C.

Age

3 days.

5 days.

11 days.

12 days.

14 days.

18 days.

25 days.

28 days.

44 days.

60 days 2

Number

of

fish

100

100

100

100

100

100

100

100

100

100

24-hour

EC0

0.10

0.10

0.06

0.06

0.04

0.06

0.10

0.04

0.08

0.10

EC100

0.40

0.60

0.20

0.20

0.10

0.40

0.40

0.20

0.40

0.60

EC50

0.30

0.35

0.14

0.15

--

0.32

0.12

0.27

0.45

C.I. 1

.12-. 42

.28-. 34

.12-. 18

.10-. 22

--

.30-. 34

.09-. 14

.24-. 30

.36-. 46

96 -hour

EC0

__

0.02

0.02

--

0.02

0.04

0.02

0.02

EC100

__

0.08

0.04

0.08

0.08

0.06

0.06

EC50

..

0.04

0.03

0.05

0.04

0.04

C.I. 1

--

.02-. 05

.02-. 04

--

.03-. 06

.02-. 05

.03-. 05

C.I. = 95-percent confidence intervals for ECso's 

2 Approximate age of our standard bioassay fjsh

resistant than the fry of bowfin and rainbow 

trout. In standard bioassays at 22° C., the 

96-hour EC 50 was 1 p.p.b. For those fry exposed to the toxicant for only 2 hours at 26° C., 

the EC 50 was 26.9 p.p.b. and the ECi00 was 

50 p.p.b.

Newly hatched fry of largemouth bass also 

were exposed to antimycin for a 2-hour period 

at concentrations of 0.01 to 0.50 p.p.b. Many 

of the control fry died, however, which makes 

interpretation of the results difficult. There 

was a 100-percent mortality of fry exposed 

to 0.075 p.p.b. within the following 96 hours, 

but there was a 60-percent mortality during 

the same period in the control lot of fry. 

Eighty-two of the 100 fry exposed to the 

lowest concentration of antimycin, 0.01 p.p.b., 

died within the following 96 hours.

Juveniles and adults. Most of the tests 

of antimycin against larger fish were run in 

vinyl or concrete pools. An early series in 

1,000-gallon, vinyl pools at 15.5° to 17.2° C., 

pH 8.4 to 8.6, and total hardness of 252p.p.m. 

included 10 species of fish. Five p.p.b. or less 

of toxicant killed all goldfish, carp, fathead 

minnow, bigmouth buffalo, green sunfish, 

pumpkinseed, bluegill, and largemouth bass 

within 144 hours (table 11). Most black bullheads and some channel catfish survived 

exposures to 10 and 20 p.p.b. Naiads of damsel 

flies and aquatic plants in the pools were 

unharmed by the antimycin. Subsequent restocking with small bluegills indicated that 

the toxicant had degraded within the first 

144 hours.

Followup bioassays in vinyl pools determined the concentration of antimycin necessary to kill black bullheads. Included were 

40, 80, 120, 160, and 200 p.p.b. of toxicant 

at 26.6° C., pH 9.0 to 9.6 and five species 

of fish. The 3.6-inch goldfish, 2.8-inch carp, 

2.7-inch green sunfish, and 4.9-inch bluegills 

were killed within 24 hours by all concentrations. The 5-inch wild black bullheads 

exhibited stress within 3 hours at 160 and 

200 p.p.b., but they recovered fully within 

24 hours. At these relatively high levels of 

pH, the toxicant degraded within 48 hours.

In contrast, 5-inch black bullheads alone 

in a test at 23° C., pH 7.8 to 8.6, and 287 

p.p.m. total hardness, died within 24 hours 

in 160 and 200 p.p.b. of antimycin. None 

died at lower concentrations. The toxicant 

lasted longer at this range of pH, and degradation was not considered complete until 96 

hours.

Fifteen-inch white catfish and 6-inch green 

sunfish were exposed up to 144 hours in 1, 5, 

and 25 p.p.b. of acetone- or sand-formulated 

antimycin in vinyl pools at temperatures 

which ranged between 1° and 16° C., pH 6.2 

to 7.0, and total hardness of 18 to 40 p.p.m. 

All white catfish survived, but the green 

sunfish died in either formulation at 5 p.p.b. 

The average degradation time for the acetone 

formulation was a little more than 7 days; 

for the sand formulation it was slightly less 

than that.

A separate series of tests was performed 

with acetone-antimycin against large f ingerling
14 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE ll.--Toxicity of antimycin to various species and sizes of fish in outdoor, vinyl pools at 15.5° to 17.2° C., pH 8.4 to 

8.6, and 252 p.p.m. total hardness

Species

Goldfish. ............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do..............

Do..............

Do..............

Do. .............

Do..............

Do..............

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Black bullhead.......

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do..............

Do..............

Do. .............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do. .......... ...~

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do..............

Number 

of 

fish

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

20 

20 

20 

20 

20 

20

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

Average size

Length 

(in.)

2.5

11 

it

4.1

it

n

ii

2.2

ii

n 

n 

n

6.4 

n

n 

2.2

7.2

n 

n 

n

2.3

5.7 

2.4 

1.5 

2.8

3.0

n

n

Weight 

(g.)

4.2 

11

n

24.1 

ii

2.5 

n

n 

56.4

4.0 ii

102.0 

n

ii 

n

2.6

30.1 

ii

n 

1.8

11

1.0 

n

5.4

8.4 

n

Antimycin 

(p.p.b.)

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Control 

0.5 

1.0 

5.0 

10.0 

20.0

Fish mortality at 1

6 

hours

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0 

0 0' 

0 

P 

T 

P

0 

0 

0 

0

P

0

0 

0 

0

P 

P

T

0 

0 

0 

0 

0 

0

0 

.0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0

P

0 

0 

0

P 

P

T

0 

0 

0

P 

P 

P

0 

0 

0 

0 

0 

0

24 

hours

0 

0 

0 

0

P 

P

0 

0 

0 

0

P 

P

0

P 

P

T 

T 

T

0 

0 

0 

P 

P 

P

0 

P 

P

T 

T 

T

0 

0 

0

P 

P 

P

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0

P

0 

0

P 

P

T 

T

0 

0 

0

P 

P 

P

0 

0 

0 

0

P 

P

48 

hours

0 

0 

0 

0 

P 

P

0 

0 

0 

P 

P 

P

0 

P 

P 

T 

T 

T

0 

0 

0 

P 

P 

T

0 

P 

P 

T 

T 

T

0 

0 

0 

P

T 

T

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

P

0 

0 

0 

0

P

0

P 

P

T 

T 

T

0 

0 

P 

P 

P 

P

0

0 

0

P 

P 

P

72 

hours

0 

0 

0 

P 

P 

P

0 

0 

0 

P 

P 

P 

P 

P 

P 

T 

T T

0 

0 

0 

P 

P 

T

P 

P 

T 

T 

T 

T

0 

0 

0 

P

T 

T

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

P

0 

0 

0 

0

P

0

P

T 

T 

T 

T

0 

P 

P 

P 

P 

T

0 

0 

P 

P 

P 

P

96 

hours

0 

0 

0

P 

P 

P

0 

0 

0

P 

P 

P 

P 

P 

P

T 

T 

T

0 

0 

0

P

T

P 

P

T 

T 

T 

T

0 

0 

0 

P

T 

T

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

P

0 

0 

0 

0

P

0

P

T 

T 

T 

T

0 

P 

P

P 

T 

T

0 

P 

P 

P 

P 

P

144 

hours

0 

P 

P 

P 

P 

P

0 

P 

P 

P 

P 

P

P 

P 

T 

T 

T 

T

0 

0 

P

T 

T 

T

P 

T 

T 

T 

T 

T

0 

0 

P

T 

T 

T

0 

0 

0 

0 

0 

0

0 

0 

0 

0 

0 

0

P 

P 

P 

0 

0 

P

0 

T 

T 

T 

T 

T

0 

P 

P

P 

T 

T

0 

P 

P 

P 

T 

T

Totals

Alive

10 

17 

17 

0 

0 

0

26

20 

21 

0 

0 

0

12 

5 

0 

0 

0 

0

30 

30 

22 

0 

0 

0

28 

0 

0 

0 

0 

0

18 

19 

12 

0 

0 

0

16 

14 

20 

18 

18 

21

27 

28 

25 

25 

30 

30

19

1 

4 

17 

13 

2

30 

0 

0 

0 

0 

0

27 

15 

0 

0 

0 

0

24

7 

0 

0 

0 

0

Dead

0 

1 

1 

20 

16 

17

0 

1 

1 

26 

29 

27 

2 

17 

30 

30 

30 

29

0 

0 

6 

30 

30 

30

2

30 

30 

30 

30 

30

1 

1 

1 

20 

19 

17

0 

0 

0

1 

1 

0

0 

0 

0 

0 

0 

0

11

20 

26 

13 

15 

28

0 

30 

30 

30 

30 

30

0 

12 

17 

18 

18 

20

0 

13 

26 

30 

26 

25

Lost

2 20 

12 

12 

10 

14 

13

4 

9

8 

4

1 

3

16 

8 

0 

0 

0 

1

0 

0 

2 

0 

0 

0

0 

0 

0 

0 

0 

0

1

0 

7 

0

1

3

14 

16 

10 

11 

11 

9

3 

2

5 

5 

0 

0

0 

9 

0 

0 

2 

0

0 

0 

0 

0 

0 

0

3 

3 

13 

12 

12 

10

6

10 

4 

0 

4 

5

See footnotes at end of table.
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 15

TABLE ll.~Toxicity of antimycin to various species and sizes of fish in outdoor, vinyl pools at 15.5° to 17.2° C., pH 8.4 to 

8.6, and 252 p.p.m. total hardness continued

Species

Do. .............

Do. .............

Do. .............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Do. .............

Do..............

Do. .............

Do. .............

Number 

of 

fish

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

30 

30 

30 

30 

30 

30

10 

10 

10 

10 

10 

10

Average size

Length 

(in.)

1.6 

5.3 

3.0 

7.2

Weight 

(g.)

0.8

it

50.0 

5.2 

81.0

Antimycin 

(p.p.b.)

Ctontrol 

0.5 

1.0 

5.0 

10.0 

20.0

Ctontrol 

0.5 

1.0 

5.0 

10.0 

20.0

Ctontrol 

0.5 

1.0 

5.0 

10.0 

20.0

Ctontrol 

0.5 

1.0 

5.0 

10.0 

20.0

Fish mortality at 1

6 

hours

0 

0 

0

P 

P 

P

0 

0 

0 

0 

0

P

0

0

P 

P 

P

T

0 

0 

0 

0 

0 

0

24 

hours

0

P 

P 

T 

T 

T

P 

P 

P 

P 

P 

P

0 

0

P 

P 

T 

T

0 

0 

0 

0 

0

P

48 

hours

0

T 

T 

T 

T 

T

P

P 

P 

P 

P 

P

0

P 

P 

T 

T 

T

0 

0 

0

P 

P 

P

72 

hours

0

T 

T 

T 

T 

T

P 

P 

P 

P 

P 

P

0

P 

P 

T 

T 

T

0

P 

P 

P 

P 

P

96 

hours

0

T 

T 

T 

T 

T

P 

P 

P 

P 

P 

T

P 

P 

T 

T 

T 

T

0

P 

P 

P 

P 

P

144 

hours

0

T 

T 

T 

T 

T

P 

P 

P 

T 

T 

T

P 

P 

T 

T 

T 

T

0

P 

P 

P 

T 

T

Totals

Alive

30 

0 

0 

0 

0 

0

9 

0 

0 

0 

0 

0,

0 

11 

0 

0 

0 

0

9 

6 

0 

0 

0 

0

Dead

0 

30 

30 

30 

30 

30

10 

23 

26 

25 

20 

25

20 

19 

30 

30 

30 

30

0 

4 

8 

10 

10 

8

Lost

0 

0

0 

0 

0 

0

11 

7 

4 

5 

10 

5

10 

0 

0 

0 

0 

0

1 

0 

2 

0 

0 

2

1 0 = no mortality, P = partial mortality, T = total mortality.

2 Unaccountable loss from pools, due in part to predatory birds.

flathead catfish in vinyl pools which contained 

water of 42 to 48 p.p.m. in total hardness and 

pH 6.6 to 7.0. One group of 4.5-inch fish 

survived 96-hour exposures to 50 p.p.b. of 

antimycin at 21° C. The 96-hour EC50 for a 

group of 5.8-inch flatheads was 54 p.p.b. at 

27° C. In a test at 28° C., the 24-, 48-, and 

72-hour EC go's for 5.8-inch finger lings was 

33 p.p.b. Most of the deaths at 27 and 28° C. 

were within the first 6 hours of the test. In a 

separate experiment, the 96-hour EC 50 for 

adult flathead catfish at 17° C. was 182 p.p.b. 

(95-percent C.I. = 158-209).

Eight species of fingerling and larger fish 

were exposed to 0.1, 1.0, and 5.0 p.p.b. of 

antimycin under ice cover. The sand formulation was applied in vinyl pools containing water 

at 190 and 282 p.p.m. total hardness and pH 

8.5 to 9.0. The activity of the toxicant was 

influenced far more by the temperature under 

5 to 6 inches of ice than by water quality. 

Concentrations of 0.1 and 1.0 p.p.b. caused 

no significant mortality of fish. Five p.p.b. 

of toxicant killed 5.8-inch rainbow trout and 

5.9-inch brown trout within 72 hours, and 1.6- 

inch carp and 3.1-inch longear sunfish within 

120 hours (table 12). There were some deaths 

among 1.4-inch goldfish, 2.1-inch fathead 

minnow, and 1.4- and 2.8-inch bluegill. No 

deaths occurred among 3.8-inch goldfish, 7.2-

inch carp, and 2.6-inch pumpkinseeds. At 

the relatively high pH,the toxicant degraded 

to a point harmless to brown trout within 

120 hours after application.

Some tests with adults of resistant species 

were made indoors in concrete tanks with 

well water at total hardness of 300 p.p.m., 

pH 7.6, and 14.5° C. Some of the shortnose 

gar died at 15 and 20 p.p.b. of sand-formulated antimycin, but 25 p.p.b. were required 

for complete kills within 96 hours (table 13). 

All bowfin died at 20 p.p.b. In sharp contrast, 

black bullheads showed 50-percent mortality 

at 140 p.p.b. and 100-percent died at 220 p.p.b. 

Their resistance to the toxicant, therefore, is 

at least 10 times that of gar and bowfin.

SIMULATED FIELD TRIALS

Community bioassays with juvenile and adult 

fish in 0.01-acre concrete pools provided 

further evidence on the concentrations of 

antimycin needed to kill certain species. The 

pools were 3.5 feet deep, the water temperatures were 11° to 21° C., pH ranged from 

7.9 to 8.6, total hardness from 252 to 290 

p.p.m., and total alkalinity from 211 to 250 

p.p.m. The concentrations of dissolved oxygen 

ranged from 8.1 to 11.2 p.p.m. Under these
16 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 12. Toxicity of 5 p.p.b. of antimycin in sand formulation to fish in vinyl pools under 5 to 6 inches of 

ice cover, total hardnesses of 190 and 282 p.p.m. and pH 8.5 to 9.0

Species

Do. .............

Do. .............

Bluegill. ...........

Do..............

Longear sunfish.. . ..

Number 

of fish 

per pool

10 

10

10 

10

10 

10

10

20 

10

10 

10

Average size

Length 

(in.)

5.8 

5.9

1.4 

3.8

1.6 

7.2

2.1

1.4 

2.8

2.6 

3.1

Weight 

(g.)

32.0 

38.0

0.7 

22.8

0.9 

82.2

1.6

0.7 

5.2

6.0 

8.0

Cumulative kill (hrs.)

Hardness of 190 p. p.m.

6

0 

0

0 

0

0 

0

0

0 

0

0 

0

24

1 

0

2 

0

0 

0

0

0 

0

0 

0

48

9 

3

1 

0

3

0

0

2

0

0 

2

72

10 

10

5 

0

3 

0

0

10

1

0 

3

96

5 

0

9

0

0

15

1

0 

9

120

6

0

10

0

0

16

1

0 

10

Cumulative kill (hrs.)

Hardness of 282 p. p.m.

6

0 

0

0 

0

0 

0

0

0 

0

0 

0

24

2

0

0 

0

0 

0

0

0 

0

0 

0

48

10 

5

0 

0

1 

0

0

8 

0

0

1

72

10

5 

0

6

0

0

16

0

0 

5

96

9

0

10

0

0

20

1

0 

10

120

9

0

0

1

3 

0

TABLE 13. Toxicity of sand-formulated antimycin to adults of three resistant species in 96 hours at 14.5° C.

Species

Number 

per 

concentration

5 

5 

50

Length (in. )

Average

23.0 

22.0 

6.5

Range

20.0-26.0 

16.0-24.0 

5.5- 9.0

Percent mortality at concentrations of (p.p.b.) 1

10

0 

20

15

20 

60

20

80 

100

25

100 

100

90

0

120

14

140

50

180

74

220

100

1 There was no mortality among controls of each species.

conditions, 1 p.p.b. of sand-formulated antimycin killed all rainbow trout and 86 percent 

of the bluegills but failed to affect the two 

size groups of goldfish and the carp (table 14). 

Two p.p.b. killed all spotted suckers and 

green sunfish as well as the trout and bluegills. Four p.p.b. was the lowest concentration at which all carp perished, but a small 

number of the larger goldfish survived both 

4 and 5 p.p.b. All fish of the 12 species 

were eradicated by 10 p.p.b.

Caged rainbow trout of finger ling size were 

placed in the pools each 24 hours. Their 

survival showed that the toxicant degraded 

to a safe level for the species within 8 days 

in every test in all pools.

A cold-weather test in the 0.01-acre pools 

demonstrated that Fintrol-5 is effective against 

fish in cold, shallow, clear, or turbid waters. 

The pools were maintained at 2 feet deep 

during the 3-week trial. Water temperatures 

ranged from 3.4° to 5.5° C.,pH from 7.4 to

8.2, total hardness from 260 to 320 p.p.m., 

and alkalinity from 235 to 260 p.p.m. The 

Secchi disk reading was 6 inches in four 

turbid pools and to the bottom in four clear 

pools.

Juvenile or adult brown trout, carp, bluegill, and largemouth bass in clear pools 

succumbed within 2 to 7 days to 5 p.p.b. of 

antimycin and within 1 to 3 days at 10 p.p.b. 

Death was delayed in turbid water; the fish 

died within 7 to 12 days at 5 p.p.b. and within 

3 to 7 days at 10 p.p.b. Large goldfish were 

the most resistant fish, but all were killed 

by 5 p.p.b. of antimycin within 15 days in 

clear water and within 18 days in turbid 

water; the kill at 10 p.p.b. occurred within 

11 days in clear water and within 16 days 

in turbid water.

Finger ling yellow perch in live cages were 

used to detect the degradation of Fintrol-5 

in the pools. The process was slow in the 

cold water, but degradation occurred sooner
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 17

TABLE 14. --Toxicity of sand-formulated antimyein to juveniles or adults of 12 species of fish in 0.01-acre pools

Species

Goldfish. ................

Do. ...................

Carp. ....................

Qaillback. ...............

Bluegill.................

Largemouth bass ..........

RlofiV r»T»QTvrff^

Number 

per concentration

10 

20 

20 

10

30 

10

35 

8 

6 

40 

30 

10 

35

Length (in.)

Average

9.9 

7.5 

4.7 

20.0

3.8 

6.9

12.1 

13.9 

14.8 

3.6 

6.0 

7.6 

9.8

Range

8.8-11.0 

6.5- 8.3 

3.5- 5.2 

12.0-22.5

3.0- 5.0 

4.8- 8.1

7.4-22.0 

8.0-16.0 

13.8-15.7 

2.8- 4.4 

4.2- 7.8 

5.4- 8.6 

8.0-11.0

Percent mortality at concentrations of (p.p.b. )

1

100

10

0 

0

0

86 

43

2

100

50

30 

0

33

100 

100 

100 

50

3

100

100

70 

30

96

100

100 

100 

100

4

100

100

80 

100

100

100 

100

5

100

100

100 90'

100 

100

100 

100

10

100 

100 

100 

100

100 

100

100

100 

100

20

100 

100 

100 

100

100 

100

100

100 

100

Control

0 

0 

0 

20

10 

0

3 

0 

0 

10 

5 

0 

20

in clear water than in turbid water. Five and 

10 p.p.b. of antimycin disappeared within 8 

and 13 days respectively in clear water and 

within 9 and 17 days in turbid water.

Water temperature has greater influence 

than turbidity on the response of fish to 

antimycin, but mortality of the fish is merely 

retarded rather than reduced in cold and 

turbid water.

TOXICITY OF INJECTED ANTIMYCIN

Injections of antimycin into the peritoneal 

cavities of fish are toxic, and the order of 

toxicity is similar to that observed when 

fish are immersed in solutions of antimycin. 

Moreover, the behavior of injected and immersed fish is similar.

Of three species, rainbow trout are the most 

sensitive to the injected toxicant. Some trout 

died at 0.01 mg. of antimycin per kg. of body 

weight, and all died within 24 hours at 0.02 

mg./kg. (table 15). Carp are intermediate in 

sensitivity to injected antimycin, with some 

dying at 0.14 mg./kg. and all dying at 0.40 

mg./kg. or more within 72 hours. In contrast, 

not less than 20 mg./kg. cause mortalities

among black bullheads, and 30 mg./kg. or more 

are needed for complete kills within 24 hours.

There were no deaths among the control 

fish of the three species which were injected 

with the ethanol-water solvent.

STABILITY OF ANTIMYCIN

The shelf life of acetone-antimycin in stock 

solutions is good in cool, dark storage. Samples held for 2 years were checked periodically 

for potency against fingerling rainbow trout. 

The 96-hour EC 50 fs and confidence intervals 

at 12° C. exhibited no greater differences in 

range than expected when using different lots 

of the same test species. Similarly, the shelf 

life of the sand formulation appears to be 

good if it is kept cool and dry, but the shelf 

life has not been measured specifically.

Antimycin can be destroyed by exposure to 

high heat for an adequate period of time. 

Crystalline antimycin which had been subjected to dry heat at 200° C. for 60 minutes 

or longer, and then dissolved in acetone and 

bioassayed was not toxic at 5 or 25 p.p.b. 

to fingerling rainbow trout within 96 hours 

(table 16). Crystals which were heated at 

200° for only 15 or 30 minutes remained as 

toxic to fish as the unheated control.
18 Investigations in Fish Control 26: Bureau of Sport Fisheries and Wildlife

TABLE 15. Toxicity of intraperitoneal injections of antimycin at 12°C.

Species

Do..................

Do. .................

Do..................

Do. .................

Do..................

Do. .................

Do..................

Do. .................

Do..................

Do..................

Do. .................

Do. .................

Do. .................

Do. .................

Do. .................

Do. .................

Weight (grams)

Average

33 

33 

33 

33

320 

335 

360 

320 

333 

300 

290 

340 

325

270 

118 

121 

150 

105 

110

Range

30-34 

30-34 

30-34 

30-34

300-330 

290-390 

300-430 

280-360 

300-370 

280-320 

265-310 

310-350 

306-340

240-300 

100-130 

110-130 

120-170 

90-140 

105-120

Injection

mg./kg.

0.002 

0.010 

0.020 

Control

0.100 

0.140 

0.160 

0.180 

0.200 

0.400 

0.600 

1.000 

Control

10.00 

20.00 

25.00 

30.00 

35.00 

Control

Fish alive/dead at~

24 

hours

5/0

Vl 

0/5 

5/0

5/0

5/0 

5/0 

5/0 

Vl 

5/0

4/0 

2/3

lA

0/5 

0/5 

5/0

48 

hours

5/0 

2/3

5/0

5/0 

Vl 

3/2 

Vl 

5/0 

2/3 

0/5 

0/5 

5/0

4/0 

2/3 

1A

5/0

72 

hours

5/0 

2/3

5/0

5/0 

2/3 

3/2 

2/3 

5/0 

0/5

5/0

4/0 

2/3 

1A

5/0

96 

hours

5/0 

2/3

5/0

5/0 

2/3 

2/3 

1A 

4/1

5/0

4/0 

2/3 

1/4

5/0

120 

hours

5/0

2/3 

2/3 

0/5 

Vl

5/0

4/0 

2/3 

1/4

5/0

TABLE 16.--Effects of oven-heating at 200° C. on the toxicity of crystalline and sand-formulated antimycin to 

fingerling rainbow trout at 12°.

[Results presented in numbers of fish alive/dead at selected intervals]

Bioassay 

time 

(hours )

0.25.......

0.50.......

1.00.......

2.00.......

3.00.......

24.00.......

96.00.......

Controls

30/0 

30/0 

30/0 

30/0 

30/0 

29/1 

29/1

Crystals at 5 p.p.b.

Nonheated

10/0 

10/0 

10/0 

10/0 

0/10

Heated (min. )

15

10/0 

10/0 

10/0 

10/0 

0/10

30

10/0 

10/0 

10/0 

10/0 

0/10

60

10/0 

10/0 

10/0 

10/0 

10/0 

10/0 

10/0

Crystals at 25 p.p.b.

Nonheated

10/0 

10/0 

0/10

Heated (min. )

30

10/0 

3/7 

0/10

60

10/0 

10/0 

10/0 

10/0 

10/0 

10/0 

10/0

120

10/0 

10/0 

10/0 

10/0 

10/0 

10/0 

10/0

Fintrol-5 at 25 p.p.b.

Nonheated

10/0 

10/0 

0/10

Heated (min. )

30

10/0 

10/0 

8/2 

3/9 

0/10

60

10/0 

10/0 

10/0 

10/0 

10/0 

10/0 

10/0

120

10/0 

10/0 

10/0 

10/0 

10/0 

10/0 

10/0

DETOXIFICATION WITH POTASSIUM 

PERMANGANATE

Although antimycin degrades rapidly in water 

(Derse and Strong, 1963; Walker, Lennon, and 

Berger, 1964), it may sometimes be desirable 

to detoxify treated waters. Potassium permanganate was included among candidate detoxifiers because of its activity as a strong 

oxidizer and the fact that fishery managers 

are familiar with it.

Crystalline potassium permanganate was 

dissolved in water and added at concentrations 

of 5 to 500 p.p.b. to 15-liter bioassay solutions which contained 5 p.p.b. of antimycin at 

12° C. Fingerling bluegills were added to the 

vessels 6 or 24 hours later, and their responses were noted over the following 96 

hours. The results reveal that 300 p.p.b. of 

potassium permanganate detoxifies 5 p.p.b. of 

antimycin within 6 hours. On the basis of 

these results, a detailed investigation was
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 19

initiated on the detoxification of antimycin 

by potassium permanganate; this will be reported separately.

DISCUSSION

These studies provide abundant evidence 

that antimycin has a fine potential as a fishery 

tool. It is a pure compound which fortunately 

can be formulated simply and with great 

integrity. The crystals are easily dissolved 

in quantities of acetone or ethanol which 

themselves are not harmful to fish. The 

formulations in Carbowax coated on fine sand 

also are precise and uniform. Consequently, 

fish can be exposed easily to exact quantities 

of active ingredient and with no influence 

from the carriers.

Because of these advantages, we are using 

antimycin as a reference compound in routine 

bioassays of unknown chemicals. Fish of any 

species may vary from lot to lot and from 

season to season in their sensitivity to a 

chemical. Also, fish within a lot may increase or decrease in sensitivity to a chemical depending on stresses involved in their 

holding and acclimation at the laboratory. 

These possible variations in sensitivity are 

not apparent in tests with compounds of unknown activities. We expose all lots of 

bioassay fish to antimycin, therefore, 

as a check on their sensitivity to a toxicant.

The order of toxicity of antimycin to 31 

species of fish is summarized in table 17. 

In static 96-hour bioassays, 1 p.p.b. of the 

toxicant kills the most susceptible fishes, 

including trouts, walleye, and yellow perch. 

Five p.p.b. kill fish of intermediate sensitivity, including carp and green sunfish 

which are often target coarse fish. Of the 

31 species, 27 are eliminated by 10 p.p.b., 

but up to 25 p.p.b. are needed to kill shortnose gar, bowfin, and channel catfish. White 

catfish, flathead catfish, and black bullheads are comparatively resistant to antimycin and up to 200 p.p.b. is required for 

eradication.

TABLE 17. Order of toxicity of antimycin to 31 

fishes, including various life stages at different 

water temperatures and qualities

1.0 p.p.b: 

Rainbow trout 

Brown trout 

Brook trout 

Lake trout 

Walleye 

Yellow perch

5.0 p.p.b.: 

White sucker 

Smallmouth bass 

Freshwater drum 

Black crappie 

Bigmouth buffalo 

Quillback 

Spotted sucker 

Northern pike 

Carp

Longear sunfish 

Bluegill

5.0 p.p.b:--Continued 

Redear sunfish 

Pumpkinseed 

Green sunfish 

Fathead minnow 

Northern redbelly dace 

Brook stickleback 

Largemouth bass

7.5 - 10.0 p.p.b.: 

Goldfish

25 p.p.b.: 

Shortnose gar 

Bowfin 

Channel catfish

200 p.p.b.: 

White catfish 

Flathead catfish 

Black bullhead

In addition to the species above, other fish 

are known to be killed by antimycin. Walker, 

Lennon, and Berger (1964) listed gizzard shad 

(Dorosoma cepedianum), stoneroller (Campostoma anomalum), golden shiner (Notemigonus 

crysoleucas). yellow bullhead (Ictalurus 

natalis), brown bullhead (Ictalurus nebulosus), 

white crappie (Pomoxis annularis). and Iowa 

darter (Etheostoma exile). Howell 1 found that 

antimycin at 9 p.p.b. is toxic to larvae of the 

sea lamprey (Petromyzon marinus) within 

21 hours. Lowe (1966) determined that the 

48-hour ECso for acetone-antimycin against 

spot (Leiostomus xanthurus) at 25° C. is 

0.23 p.p.b. In his trials of sand-formulated 

antimycin on juvenile fish, Lowe also found 

that 10 p.p.b. killed all longnose killifish 

(Fundulus similis) within 48 hours, and that 

the 48-hour EC50 *s for sea catfish (Galeichthys 

felis) and sheepshead minnow (Cyprinodon 

variegatus) at 19° and 23° C. are 10 and 32 

p.p.b. respectively. Meyer 2 reported that grass 

carp (Ctenopharyngoden idellus) are killed 

by 3 p.p.b. of antimycin and tilapia (Tilapia 

mossambica) by 5 p.p.b. within 24 hours in 

aquaria at room temperature.

1 Letter from John Howell, Supervisory Fishery 

Biologist, Hammond Bay Biological Station, Bureau of 

Commercial Fisheries, Millersburg, Mich., 1966.

2 Letter from Dr. Fred P. Meyer, Chief, Fish Farming 

Experimental Station, Bureau of Sport Fisheries and 

Wildlife, Stuttgart, Ark., 1966.

338-447 O - 69 - 5
20 Investigations in Fish Control 26 : Bureau of Sport Fisheries and Wildlife

Antimycin has another advantage as a fish 

control agent: fish are not repelled or excited 

by its presence in water. This, coupled with 

the order of toxicity and effectiveness on 

various life stages, suggests that the toxicant 

has possibilities for partial or selective control of fish. The lethal effects on fish eggs, 

for example, indicate that it might be employed effectively in spawning areas for partial 

control of unwanted species. Or it might be 

useful for control of trash fish in catfish 

production ponds. There are also possibilities 

worth investigating that the sand formulations, Fintrol-5 and Fintrol-15, might be 

used in littoral zones or epilimnions of 

thermally stratified lakes to remove stunted 

or unwanted fish.

Certain facts disclosed by the studies point 

to a possible usefulness of antimycin in reclaiming streams. They include the lack of 

color, odor, or repellency in the toxicant, 

the relatively brief exposures needed to kill 

fish, the relatively rapid rate of degradation, 

and the susceptibility of the antibiotic to 

detoxification with potassium permanganate.

Also, from the point of view of fishery 

management, the toxicant is effective in a 

variety of water qualities. High pH contributes 

to more rapid degradation of antimycin, but 

this might be an advantage in certain situations so long as the concentrations applied 

persist through an effective contact time. 

Temperature has less effect on the activity 

of the toxicant than pH, but somewhat greater 

concentrations may be required in very cold 

waters and under ice than in waters of 

moderate temperature. Water hardness has 

less influence on antimycin than pH or temperature, but toxicity is slightly greater in 

soft water than in hard water.

A mineral turbidity may retard or reduce 

the toxicity of antimycin to fish, depending 

on the amount of material in suspension and 

whether it remains in suspension or settles 

out. Similarly, Ferguson et al. (1966) reported that muds reduce the bioactivity of 

chlorinated hydrocarbon insecticides on fish.

As an outgrowth of these laboratory trials, 

the development of antimycin as a fishery 

tool has begun to include comprehensive 

tests of its toxicity to birds and mammals 

(Vezina, 1967), and experimental applications against fish in lakes and streams 

(Lennon, 1966; Berger, 1966). Lennon, 

Berger, and Gilderhus (1967) adapted seed 

spreaders for distributing sand-formulated antimycin in field operations. Powers 

and Bowes (1967) used antimycin to control predaceous fish in a grebe refuge in 

Guatemala. Hogan (1967) and Burress 

and Luhning (1969) investigated the utility of 

antimycin in channel catfish production. 

Walker (1967) has further defined the amounts 

of potassium permanganate needed to detoxify various concentrations of antimycin 

in water.

CONCLUSIONS

1. Antimycin in water or injected intraperitoneally is toxic to fish. Various life 

stages of some species of fish were included in tests, and the antibiotic was 

toxic to all, egg through adult.

2. Solutions of antimycin crystals in acetone 

orethanolor dry preparations in Carbowax 

on sand are stable in storage, irreversibly 

toxic to fish in waters of various qualities 

and temperatures, and subject to detoxification by potassium permanganate.

3. Natural degradation occurs sooner in hard, 

alkaline waters than in soft, acid waters. 

The degradation products are not toxic 

to fish. The exposure of the antibiotic to 

dry heat at 200° C. for short periods of 

time reduces or destroys its toxicity to 

fish.

4. The purity of the compound, the integrity 

of its formulations, and its lack of repellency to fish are characteristics which 

enhance its use for general, partial, or 

selective control of unwanted fish.
Berger, Lennon, and Hogan: Antimycin A as a Fish Toxicant 21

REFERENCES

Berger, Bernard L.

1966. Antimycin (FINTROL) as a fish toxicant. Proceedings of the 19th Annual Conference of Southeastern Association of Game and Fish Commissioners, Tulsa, Okla., October 10-13, 1965, 

p. 300-301.

Burress, Ralph M., and Charles W. Luhning.

1969. Investigations in fish control: Field trials of 

antimycin as a selective toxicant in channel catfish ponds. U.S. Bureau of Sport Fisheries and 

Wildlife. 12 p.

Derse, P. H., and Fe M. Strong. 

1963. Toxicity of antimycin to fish. Nature, vol. 200, 

no. 4906, p. 600-601.

Ferguson, Denzel E., J. Larry Ludke, James P. Wood, 

and Johnny W. Prather.

1966. The effects of mud on the bioactivity of pesticides on fishes. Journal of the Mississippi Academy 

of Science, vol. 11, p. 219-228.

Hogan, James W.

1967. Antimycin as a fish toxicant in catfish culture. 

Proceedings of the 20th Annual Conference of Southeastern Association of Game and Fish Commissioners, Asheville, N.C., October 24-26, 1966.

Lennon, Robert E.

1966. Antimycin a new fishery tool. Wisconsin Conservation Bulletin, vol. 31, no. 2, p. 4-5.

____ , Bernard L. Berger, and Philip A. Gilderhus.

1967. A powered spreader for antimycin. Progressive Fish-Culturist, vol. 29, no. 2, p. 110-113.

__^_ , and Charles R. Walker.

1964. Investigations in fish control: 1. Laboratories 

and methods for screening fish-control chemicals. 

U.S. Bureau of Sport Fisheries and Wildlife, Circular 185. 15 p.

Litchfield, J. T., Jr., and F. Wilcoxon. 

1949. A simplified method of evaluating dose-effect 

experiments. Journal of Pharmacology and Experimental Therapeutics, vol. 96, no. 2, p. 99-113.

Loeb, Howard A.

1964. Some notes concerning the toxicity of antimycin 

A to carp and other fish. New York Fish and Game 

Journal, vol. 11, no. 2, p. 160-161.

Lowe, Jack I.

1966. Quarterly Program Progress Report, Biological Laboratory, Bureau of Commercial Fisheries, 

Gulf Breeze, Fla.; April 1-June 30, 1966, p. 4.

Powers, James E., and Anne LaBastille Bowes.

1967. Elimination of fish in the Giant Grebe Refuge, 

Lake Atitlan, Guatemala, using the fish toxicant, 

antimycin. Transactions of the American Fisheries 

Society, vol. 96, no. 2, p. 210-213.

Strong, Frank M., and Philip H. Derse.

1964. Method of killing fish with antimycin. Patent 

3,152,953, U.S. Patent Office, Washington, October 

13. 2 p.

Valentine, Joseph John.

1966. Effects of antimycin A upon the development of 

zebra fish embryos. Masters thesis (unpublished), 

University of Connecticut. 21 p.

Vezina, Claude.

1967. Antimycin A, a teleocidal antibiotic. In Symposium on nonpharmaceutical uses of antibiotics: 

Antibiotics in wildlife management, Paper 155. 

Sixth Interscience Conference on Antimicrobial 

Agents and Chemotherapy, October 1966. p. 757-766.

Walker, Charles R.

1967. Detoxification of antimycin A with KMnO4 

and effects of water chemistry and temperature. 

15th Annual Meeting of the Midwest Benthological 

Society, Carbondale, 111., April. 16 p.

Walker, Charles R., Robert E. Lennon, and Bernard L. 

Berger.

1964. Investigations in fish control: 2. Preliminary 

observations on the toxicity of antimycin A to fish 

and other aquatic animals. U.S. Bureau of Sport 

Fisheries and Wildlife, Circular 186. 17 p.
INVESTIGATIONS IN FISH CONTROL

27. Field Trials of Antimycin A 

as a Fish Toxicant

By Philip A. Gilderhus, Fishery Biologist, 

Bernard L. Berger, Chemist, and 

Robert E. Lennon, Fishery Biologist

United States Department of the Interior

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Washington, D.C. . February 1969
CONTENTS

	Page 

Abstract. ....................................... 3

Materials and methods .............................. 4

Antimycin A .................................. 4

Degradation or detoxification of antimycin .............. 5

Sites of field trials.............................. 5

Pre- and post-treatment surveys .................... 8

Standing water.............................. 8

Flowing Water. ............................. 8

Results. ........................................ 8

Trials in ponds and lakes. ......................... 8

Berlin, New Hampshire........................ 8

Cape Vincent, New York ....................... 10

Stuttgart, Arkansas. .......................... 11

Valentine, Nebraska .......................... 12

Saratoga, Wyoming. .......................... 13

West Salem, Wisconsin ........................ 14

Madison, Wisconsin .......................... 14

Oxford, Wisconsin ........................... 15

Trials in streams. .............................. 15

Viroqua, Wisconsin. .......................... 15

Plymouth, Wisconsin. ......................... 16

Cataract, Wisconsin .......................... 17

Westfield, Wisconsin. ......................... 17

Madison, Wisconsin .......................... 18

Effects on non-target animals. ...................... 18

Discussion ...................................... 19

Conclusions. ..................................... 20

References ...................................... 21 (
FIELD TRIALS OF ANTIMYCIN A AS A FISH TOXICANT

By Philip A. Gilderhus, Bernard L. Berger, and Robert E. Lennon

Bureau of Sport Fisheries and Wildlife 

Fish Control Laboratory, La Crosse, Wisconsin

ABSTRACT. Antimycin A was subjected to field trials as a fish toxicant in 20 ponds and lakes and 5 streams in the East, Midwest, and West 

of the United States, 'rhe formulations of toxicant included three on sand 

grains which are designed to release antimycin uniformly within certain 

depths, and one formulation in a liquid. Ten parts per billion or less of 

the toxicant were effective against most of the 54 species of fish we encountered, including carp, suckers, and green sunfish. Differences in 

sensitivity among fish suggest possible use of antimycin as a selective 

toxicant. The efficacy of the toxicant is influenced by pH and water temperature, with slightly higher concentrations necessary at high pH or in 

cold water. Antimycin does not repel fish, and its toxic action on fish appears to be irreversible. It degrades rapidly, usually within a week. Fishkilling concentrations have little or no effect on other aquatic animals.

The development and registration of a fish 

toxicant require that the candidate chemical 

be tested thoroughly in the laboratory and in 

the field to evaluate its toxicity to different 

forms of invertebrate and vertebrate life, its 

efficacy on fish, and its residues in water and 

fish. The trials in the field must involve at 

least three ecologically different sites, and 

target and other organisms typical of those 

sites. Also, they must be organized, executed, 

and reported as controlled experiments, and 

the data from them are reviewed in detail by 

regulatory agencies at Federal and State 

levels before the toxicant may be registered 

for use. Notably, the regulatory authorities 

warn against submitting the once-common 

testimonial type of reports on field trials.

The field trials of antimycin A followed intensive testing in the laboratory which demonstrated its potential as a toxicant specific to 

fish (Walker et al., 1964; Vezina, 1967; 

Herr et al., 1967; and Berger et al., 1969). 

The sites were chosen and the trials conducted with the requirements for registration 

in mind. Thus, waters in the East, Midwest,

and West of the United States were included. 

Soon after each of the early trials, a report 

was submitted to the Pesticide Regulation 

Division of the U.S. Department of Agriculture for review and for suggestions on points 

to consider in subsequent trials.

The objectives of the field trials were:

1. to evaluate the efficacy of antimycin A in 

several formulations against as many 

species of fish as possible in cold and 

warm waters, acid and alkaline waters, 

and clear and turbid waters,

2. to determine concentrations of antimycin 

which are effective against such prime 

target fish as carp, suckers, and green 

sunfish,

3. to observe any effects of the toxicant on 

other aquatic animals,

4. to detect whether or not the toxicant repels 

fish,
4 Investigations in Fish Control 27; Bureau of Sport Fisheries and Wildlife

5. to find out if the toxic action in fish is irreversible,

6. and to observe the rates of natural and induced degradation of antimycin in water.

The early trials were conducted on very 

small ponds for two reasons. First, the tests 

were easier to control and evaluate than in 

larger waters. Second, the quantities of 

formulated antimycin were limited because 

pharmacologists of the producing company 

were then in the midst of developing and perfecting the Fintrol formulations.

Concurrently, field trials by other investigators bolstered the development of antimycin 

as a fish toxicant (Loeb, 1964; Lennon, 1966; 

Lennon et al., 1967; Powers and Bowes, 1967; 

Powers and Schneberger, 1967; Radonski, 

1967; Burress, 1968; and Burress and 

Luhning, 1969a and 1969b).

The successful accomplishment of field 

trials was made possible only through the 

generous cooperation of many people. We are 

indebted especially to fishery personnel of 

State conservation departments who provided 

experimental sites, stocked fish, and manpower; to fishery and wildlife personnel in 

Bureau hatcheries, refuges, and laboratories 

who also provided trial sites, fish, and aid; to 

Wisconsin Alumni Research Foundation, 

owners of antimycin, for advice and aid; to 

Ayerst Laboratories, producers of antimycin, 

for supplying the pure and formulated toxicant 

at no charge; and to personnel of the Pesticide Regulation Division, U.S. Department of 

Agriculture, for counsel on the scope and 

depth of experimental data needed for registration of antimycin as a fishery tool.

MATERIALS AND METHODS

Antimycin A

The early development of antimycin A as a 

fish toxicant included much consideration and 

investigation of formulations to meet the requirements of fish managers. A liquid formulation was needed for application in streams 

and in the very shallow waters of ponds and

marshes. Accordingly, an experimental 

Fintrol-Liquid was prepared, consisting of 

crystalline antimycin dissolved in acetone or 

ethanol with a small amount of surfactant 

added.

We recognized the long-standing problem 

that fish managers have experienced in getting 

adequate distribution of liquid or powered 

toxicants into the deeper waters of ponds and 

lakes, especially when thermal stratification 

exists. We sought granular formulations, 

heavier than water, which would release 

antimycin within selected depths. Thus, the 

cumbersome and often imperfect job of pumping a toxicant into the depths of a lake would 

be avoided. As a result of cooperative efforts 

among scientists of Ayerst Laboratories, 

Wisconsin Alumni Research Foundation, and 

the Bureau of Sport Fisheries and Wildlife, 

experimental formulations of antimycin on 

sand were developed.

The sand formulations consist of antimycin 

incorporated in Carbowax^ and coated on 

sand in such a way that the toxicant is released into the water within certain depths as 

the sand grains sink toward the bottom. Because we expected that most of the early applications of antimycin would be in production 

ponds, farm ponds, and small lakes, we chose 

formulations on sand which would release the 

toxicant evenly within the first 5, 15, and 30 

feet of depth. They are called Fintrol-5, 

Fintrol-15, and Fintrol-30, respectively. Of 

them, only Fintrol-5 is registered and on the 

market. Formulations for release of toxicant 

over greater depths or for delayed release 

on the bottom are possible and may be developed later.

All of the formulated antimycin used in the 

field trials was prepared and furnished by 

Ayerst Laboratories, New York, N.Y.

The liquid formulation of antimycin was 

applied to streams and shallows of ponds by 

means of spray apparatus or metering pumps. 

In most cases, a strong solution of FintrolLiquid in water was prepared on site and 

promptly dispensed. Metering pumps of the 

type described by Anderson (1962) gave the 

best performance.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant

The formulations of antimycin on sand were 

broadcast by hand, by hand-operated seed 

spreader, or by powered seed spreaders 

mounted on boats (Lennon et al., 1967). An 

attempt was made on each job to achieve as 

rapid and as even distribution as possible.

Degradation or Detoxification 

of Antimycin

The degradation of the toxicant in ponds 

was determined by field bioassays. Fingerling 

rainbow trout or bluegills were placed in live 

cages and submerged at selected sites and 

depths in the ponds at least 24 hours prior to 

the application of antimycin. Each live cage 

contained at least 10 specimens of a species 

and size of fish.

Following application of the toxicant, the 

fish in live cages were checked frequently 

during the first 36 to 48 hours to detect the 

rate and amount of mortality. As soon as all 

specimens of a species in a live cage were 

dead, a replacement lot was provided. The 

survival of all specimens in a live cage for 

at least 48 hours was indicative that the toxicant had degraded below the lethal concentration or had flowed from the vicinity.

Potassium permanganate was used during 

two field trials to detoxify the antimycin in 

effluent waters. Solutions or crystals of

KMnC>4 were applied to obtain concentrations 

of 1 to 2 p.p.m. in the water.

Sites of Field Trials

The 13 sites selected for field trials of 

antimycin included 20 ponds or lakes and 5 

streams (tables 1 and 2). The first trials were 

conducted on Bureau property and involved 14 

ponds which are not subject to public fishing. 

These selections were made not only to obtain good tests of the toxicant, but also as a 

precaution against undue risks to the public 

until we knew more about the performance of 

antimycin in the field.

The ponds and lakes ranged in area from 

0.25 to 63 surface acres and in volume from 

0.45 to 787 acre-feet (table 2). The streams 

were small and ranged in volume of flow 

from 2 to 20 c.f.s. The ranges in water constituents were: pH, 7.0 to 8.8; total hardness, 

10 to 350 p.p.m.; and total alkalinity, 13 to 

350 p.p.m. (tables 2 and 3). Water temperatures ranged from 5° to 20° C., and all temperatures in this report are expressed in 

Celsius.

Fifty-four species of freshwater fish were 

represented in the trials, and they included 

such problem species as carp, white suckers, 

and green sunfish (table 4). In the early trials 

in small ponds, known numbers and sizes of 

fish were stocked to facilitate evaluations on 

the performance of the toxicant.

TABLE 1. Sites of field trials with antimycin A

Town and state

1. Berlin, N.H. .......

2. Cape Vincent, N.Y. . 

3. Stuttgart, Ark..... 

4. Valentine, Neb.....

6. West Salem, Wis....

8. Oxford, Wis........

9 V"? T*nmifl UT? ss

11. Cataract, Wis......

12. Westfield, Wis..... 

13. Marshall, Wis......

Site

Ponds and lakes

Berlin MFH1

Cape Vincent MFH 

Warmwater Fish Cultural Laboratory 

Valentine NWR2

Venterans Memorial Park

Streams

Mullet River

Westfield Creek 

Waterloo Creek

Owned or managed by

Bureau of Sport Fisheries and Wildlife 

Bureau of Sport Fisheries and Wildlife 

Bureau of Sport Fisheries and Wildlife

La Crosse County, Wisconsin

State of Wisconsin 

State of Wisconsin

1 national Fish Hatchery

2 National Wildlife Refuge
6 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

TABLE 2. Physical and chemical characteristics of ponds and lakes

Site

1. Berlin NFH......

2. Cape Vincent NFH

3. Warmwater Fish

Cultural

Laboratory .

4. Valentine NWR. ..

5. Saragoga NFH....

6. Veterans

Memorial Park.

7. Lake Katrine....

8 . Parker Lake .....

Date

9/64

10/64

3/65

12/65

5/65

10/65

11/65

5/66

10/66

in/66

Pond 

or

lake

PI

P2

P3

PI

P2

P3

PI

P2

P3

P4

P5

P6

LI

L2

PI

P2

--

..

Surface 

area 

(acres)

_

1.00

1.00

1.00

0.25

0.25

0.25

0.25

0.25

0.25

19.40

0.25

1.80

0.50

1.79

4.78

2.70 2

30.00

ft^ nn

Volume 

(acrefeet)

0.45

1.16

0.55

2.93

2.55

2.74

0.58

0.58

0.58

0.58

0.58

0.58

42.68

0.58

3.24

1.95

5.84

21.51

10.01

118.00

7rt7 nn

Water 

temp.

(°c.)

12

13

12

12

12

12

17

17

17

17

17

17

12

12

19

20

9

13

17

18

q

Chemical characteristics

DO 

(p. p.m.)

9.6

9.4

9.0

8.9

8.7

8.0

9.6

10.4

9.6

10.4

9.6

10.4

10.8

7.4

8.3

--

COa 

(p. p.m.)

0.1

0.1

0.1

2.5

3.0

3.2

1.0

1.0

1.0

1.0

1.0

1.0

_

0.0

0.9

--

--

PH

7.0

7.2

7.2

8.1

7.9

8.1

8.0

8.1

8.2

8.2

8.1

8.2

8.6

7.9

8.4

7.9

7.7

7.8

6.8-8.5

8.2

rt.5

Total 

hardness 

(p. p.m.)

10.0

10.0

10.0

153.0

159.0

155.0

59.0

58.0

55.0

58.0

60.0

52.0

112.0

120.0

107.0

142.0

237. O1

223.0

32.0

iQ7.n

Total 

alkalinity 

(p. p.m.)

14.2

12.8

14.5

110.5

118.0

118.0

81.0

78.0

72.0

77.0

79.0

70.0

110.0

148.0

155.0

258.0

184.0

188.0

25.0

35.0

1 Total dissolved solids

2 Partial treatment (small bay)

TABLE 3. Physical and chemical characteristics of streams

Site

9. Sidie Hollow Creek.

10. Mullet River.......

11. Rathbone Creek. ....

12. Westfield Creek....

13. Waterloo Creek.....

Date

8/65

9/66

11/66

6/67

7/67

(c.f.s.)

1.76

10.0

10.7

21.7

4.3

Length of

section

(mi.)

3.5

2.5

6.0

3.0

1.0

(ft.)

4

18

9

20

30

Water

temp.

( C.)

10 -18

20 -22

5

20

25

Chemical

characteristics

PH

8.3

8.4

7.5

8.8

8.6

Total

hardness

(p. p.m.)

240

210

24

170

350
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 7

TABLE 4.--Fish exposed to antimycin in field trials

Common name

American brook lamprey. ........

Paddlef ish. ....................

Bowfin. ........................

Gizzard shad ...................

Rainbow trout ..................

Brook trout. ...................

Central mudminnow. .............

Stoneroller. ...................

Goldfish. ......................

Golden shiner. .................

Common shiner. .................

Bluntnose minnow. ..............

Fathead minnow. ................

Blacknose dace. .................

Longnose dace. .................

Creek chub .....................

Fallfish. ......................

White sucker. ..................

Northern hog sucker. ...........

Smallmouth buffalo. ............

Bigmouth buffalo. ..............

Buffalo hybrid. ................

White catfish. .................

Blue catfish. ..................

Black bullhead .................

Yellow bullhead. ...............

Brown bullhead .................

Channel catfish. ...............

Tadpole madtom. ................

Flathead catfish. ..............

Mosquitofish. ..................

Brook stickleback. .............

White bass. ....................

Rock bass. .....................

Warmouth. ......................

Orangespotted sunfish. .........

Bluegill.......................

Smallmouth bass ................

Largemouth bass ................

White crappie. .................

Black crappie ..................

Iowa darter. ...................

Fantail darter. ................

Johnny darter. .................

Yellow perch. ..................

Walleye ........................

Freshwater drum. ...............

Scientific name

Lampetra lamottei

Polyodon spathula

Amia calva

Dorosoma cepedianum

Salmo qairdneri

Salmo salar

Salmo trutta

Salvelinus fontinalis

Umbra limi

Esox lucius

Campostoma anomalum

Carassius auratus

Cjrprinus carpio

Uotemigonus crysoleucas

Notropis cornutus

Pimephales notatus

Pimephales promelas

Rhinichthys atratulus

Rhinichthys cataractae

Semotilus atromaculatus

Semotilus corporalis

Catostomus commersoni

Hypentelium nigricans

Ictiobus bubalus

Ictiobus cyprinellus

Ictalurus catus

Ictalurus furcatus

Ictalurus melas

Ictalurus natalis

Ictalurus nebulosus

Ictalurus punctatus

Noturus gyrinus

Pylodictus olivaris

Gambusia af finis

Eucalia inconstans

Roccus chrysops

Ambloplites rupestris

Chaenobryttus gulosus

Lepomis cyanellus

Lepomis gibbosus

Lepomis humilis

Lepomis macrochirus

Micropterus dolomieui

Micropterus salmoides

Pomoxis annularis

Pomoxis nigromaculatus

Etheostoma exile

Etheostoma flabellare

Etheostoma nigrum

Perca flavescens

Stizostedion vitreum vitreum

Aplodinotus grunniens

Cottus bairdi

Sites where found 

(by number)

11, 12

3

2

3

1, 2, 3, 6, 8, 9, 12

1

2, 6, 9, 10

1, 2, 5, 11

6, 10, 11

1

2, 4, 6, 10, 13

9

3

2, 3, 4, 6, 7, 8, 10, 12, 13

1, 2, 3, 6

1

12

4, 5, 6, 7, 12

1, 9, 12

9

1, 5, 9, 10, 12

1

1, 2, 6, 9, 10, 11, 12, 13

9

3

3

3

3

3

3, 4, 6, 7

3

1, 2

3, 6

3

3

3

9, 11, 12

2

2, 10

3

3, 4, 6, 10

1, 2, 6, 8, 12

3

1, 2, 3, 4, 6, 8, 10, 12

1, 2

1, 2, 3, 4, 10, 12

6

2, 3, 4, 10

5

12

9, 10, 11, 12

1, 2, 4, 8

2

2

9, 12
8 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife 

Pre- and Post-treatment Surveys RESULTS

STANDING WATER

The ponds and lakes were mapped carefully, 

including depths and contours. Their volumes 

in acre-feet were calculated from measurements of area and depth. Analyses of water 

chemistry were made on site and correlated 

with any historical data available. The species, abundance, and sizes of fish were assessed before the trials from stocking records, or by netting or electrofishing. The 

post-treatment presence of fish was detected 

by netting, electrofishing, or by draining the 

ponds.

The populations of bottom fauna and plankton were sampled by standard techniques before and after applications of antimycin, and 

attempts were made to correlate changes in 

composition or abundance with causative 

factors.

FLOWING WATER

The streams were mapped and sounded, and 

the volumes and velocities were measured 

with a current meter. Measurements of 

stretchout and dilution were accomplished in 

soft water by the salt-resistivity technique 

(Lennon, 1959; Lennon and Parker, 1959) and 

in hard water by use of the rhodaminefluorometer technique (Buchanan, 1964). The 

losses in concentration of salt or rhodamine 

dye between selected stations on a stream 

were assumed to equal the losses of a toxicant in the same flow and distance. On the 

basis of these data, the sites of fortifying 

stations were located and the amounts of toxicant to be added at each station were determined.

Analyses of the water were made routinely 

by standard techniques. The populations of 

fish were sampled before and after applications of antimycin by electrofishing.

Trials in Ponds and Lakes

BERLIN, NEW HAMPSHIRE

Three, small earth ponds were selected at 

the Berlin National Fish Hatchery as typical 

of cold, soft, trout water in northern New 

England (tables 2, 5, and 6). Sixteen species 

of wild and hatchery-reared fish were stocked 

in known numbers at least 1 week prior to the 

experimental reclamation.

We chose a wide range of concentrations of 

antimycin because this was the first trial in 

soft water. One pond was treated with 0.13 

p.p.b., another with 1.22 p.p.b., and the third 

with 12.00 p.p.b. It was also the first field 

trial of the sand formulation, Fintrol-5.

Nine of the 12 species exposed to 0.13 

p.p.b. suffered mortalities. Only common 

shiners had a complete kill; the other species 

had partial mortalities ranging from 18 to 75 

percent. The fish in this pond, however, received only a 24-hour exposure to the toxicant. There was a large loss of water from 

the pond because of seepage, and fresh water 

had to be added each 24 hours. The fish unaffected by the relatively brief exposure to 

the low concentration were chain pickerel, 

brown bullheads, and bluegills.

The toxicant at 1.22 p.p.b. caused complete 

kills of 12 species within 72 hours, and it degraded in 120 hours. A few bluegills and 

smallmouth bass and all brown bullheads 

survived.

The 12 p.p.b. of antimycin killed the most 

sensitive species within 10 hours and all fish 

except brown bullheads within 48 hours. 

More than 2 weeks were required for this 

concentration of toxicant to degrade below 

fish-killing levels.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant

TABLE 5. Applications of antimycin and rates of degradation in field trials

Site

1. Berlin NFH. ........

2. Cape Vincent NFH...

3. Wannwater Fish

Cultural

Laboratory

March 1965

December 1965. . . .

4. Valentine MWR. .....

5 . Saratoga NFH. ......

6. Veterans Memorial

Park.

7. Lake Katrine

May 1966.........

Oct. 1966........

8. Parker Lake. .......

9. Sidie Hollow Creek.

10. Mullet River.......

(Plymouth Pond)

11. Rathbone Creek.....

(Cataract Pond)

12. Westfield Creek....

13 . Waterloo Creek. ....

Pond 

or 

lake

PI

P2

P3

PI

P2

P3

PI

P2

P3

P4

P5

P6

LI

L2

PI

P2

Formulation 

(percent 

active)

Fintrol-5, 0.19

Fintrol-5, 0.19

Fintrol-5, 0.88

Fintrol-5, 0.10

Fintrol-5, 0.29

Fintrol-5, 0.96

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-5, 1.0

Fintrol-15, 1.5

Fintrol-30, 3.2

Liquid

Liquid

Liquid,

0.37-0.52

Liquid, 10.0

Fintrol-5, 1.0

Liquid, 10.0

Liquid, 10.0

Total ' 

formulation

38 g.

940 g.

1,000 g.

3,790 g.

3,395 g.

3,675 g.

360 g.

360 g.

540 g.

540 g.

720 g.

720 g.

53 kg.

400 g.

4,018 g.

2,480 g.

T7 J. f -Kg ICCT .

22 kg.

5,000 g.

431 kg.

288 kg.

175 kg.

159 kg.

__

43 1.

1,540 ml.

11.6 kg.

6,250 ml.

1,825 ml.

Antimycin 

(g.)

0.07

0.76

8.22

3.70

9.85

35.40

3.60

3.60

5.40

5.40

7.20

7.20

526.64

4.00

40.18

24.80

17.20

220.00

50.00

4,313.00

2,883.00

2,647.00

5,130.00

100.00

_

206.50

154.00

115.70

625.00

182.00

Cone, of 

antimycin 

in water 

(p.p.b.)

0.13

1.22

12.00

1.02

3.12

10.40

5.00

5.00

7.50

7.50

10.00

10.00

10.00

10.00

10.00

10.00

10.00

10.00

4.00

7 f » -><j ^n 

10.00

15 for

5 hours

7.5 for

8 hours

7.5 for

8 hours

7.5

10 for

10 hours

10 for

5 hours

Degradation 

time 

(hrs.)

24

120

>330

96

96

96

168

168

168

168

168

168

120

120

24

120

144

96

120

168

__

--

--

TABLE 6. Effects of antimycin on fish at Berlin NFH

Fallfish.................

Bluegill. ................

Size

(inches)

3.4-3.7

4.0-4.6

10.0-12.0

4.7-5.0

2.0

3.8-4.0

4.6-4.8

9.8-10.6

10.0-10.5

5.5-6.3

7.5-7.9

4.5-4.8

3.6-6.0

7.0-8.7

Number

pond

115-116

21-22

111-112

11-12

4

3-4

13-14

8

8-9

16

9-10

12-14

9

23-28

8-11

12

F

0.13 p.p.b.

18

46

0

100

50

31

0

50

0

38

75

33

ercent killed

1.22 p.p.b.

100

100

100

100

100

100

100

100

0

100

44

86

100

100

at

12.0 p.p.b.

100

100

100

100

100

100

100

100

0

100

100

100

100

100
10 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

The results at Berlin NFH were important 

to subsequent field trials and to further development of the toxicant. Although the 0.13 

p.p.b. of antimycin was too small a concentration for a large kill of fish, the no-kill and 

partial-kill of certain species confirmed 

laboratory findings that some species are 

more sensitive than others, and that antimycin has potentials for selective control of 

sensitive fish. The concentration of 1.22 

p.p.b. was also too small for a complete kill 

of scale fish. On the other hand, the concentration of 12 p.p.b. was too high. We concluded 

that the optimum concentration for scale fish 

in the cold, soft water might have been 4 or 

5 p.p.b.

The results also confirmed laboratory observations that bullheads are very tolerant of 

concentrations of antimycin which kill most 

scale fish. This could be an advantage in 

some situations, and a disadvantage in others. 

We concluded, however, that the presence or 

absence of bullheads could be ignored in most 

of our field trials because the amounts of 

toxicant used would be too small to affect 

them.

This first test of antimycin formulated on 

sand, Fintrol-5, demonstrated that the preparation is easy and clean to handle and distribute, and the results supported a decision 

to continue development of sand formulations. 

We did recommend that a coarser grade of

sand be used as the carrier because the fine 

sand could float on surface film of water or 

could be blown from the path or distribution 

by the wind. The manufacturer then changed 

from 60-mesh sand to 40-mesh.

The pond waters were clear and colorless 

and afforded good observation of the fish during and after the application of antimycin. 

The formulation contributed no color or odor 

to the water, and the fish were not repelled by 

it. Moreover, it killed the fish slowly and unspectacularly.

CAPE VINCENT, NEW YORK

Three 1-acre ponds at the Cape Vincent 

NFH were stocked with 20 species of fish and 

treated with the sand formulation of antimycin. The water was harder and more fertile than at Berlin NFH, and the ponds contained substantial amounts of rooted, aquatic 

vegetation.

We narrowed the range of test concentrations to 1.02, 3.12, and 10.4 p.p.b. of antimycin (table 7). The lowest concentration 

killed all trouts, certain minnows, white 

suckers, and yellow perch. Seven species had 

partial mortalities ranging from 17 to 97 percent, and seven species had no mortalities. 

Only bowfin and brown bullheads and some of 

the pumpkinseeds, smallmouth bass, largemouth bass, and black crappies survived

TABLE V. Effects of antimycin on fish at Cape Vincent NFH

Species

Bluegill................

Walleye

Size 

( inches )

16.2-18.8 

7.7-9.0 

9.0-10.3 

9.9-10.7 

14. 5-17.1 

2.3-2.5 

16.8-17.4 

2.4-3.0 

2.9-3.1 

17.1-19.2 

4.2-5.3 

15.4 

7.0-8.0 

4.5-6.2 

7.6-8.2 

11.5 

12.0-14.0 

6.8-8.0 

7.2-8.0 

12.1-16.5 

16.0-18.0

Number 

per 

pond

1 

5-10 

5-6 

5-6 

2-3 

100 

1 

70-80 

29 

2-8 

29-30 

0-1 

7-8 

10-22 

9-30 

0-1 

19 

10-12 

9 

4-5 

1-2

Percent killed at

1.02 p.p.b.

0 

100 

100 

100 

0 

94 

0 

100 

97 

100 

0 

0 

17 

45 

88 

0 

0 

70 

100 

50 

0

3.12 p.p.b

0 

100 

100 

100 

100 

100 

100 

100 

100 

100 

0

100 

88 

100 

63 

63 

67 

100 

100 

100

10.4 p.p.b.

0 

100 

100 

100 

100 

100

100 

100 

100 

0

100 

100 

100 

100 

100 

100 

100 

100 

100
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 11

exposure to 3.12 p.p.b. Notably, the species 

eliminated by this concentration included 

juvenile and adult carp, minnows, and white 

suckers.

Exposure to 10.4 p.p.b. of antimycin killed 

17 of the 19 species, leaving only bowfin and 

brown bullheads. Comparing the results obtained with 3.12 and 10.4 p.p.b., we concluded 

that the latter concentration was too high for 

most of the species involved in the trials.

The sand formulation worked well in the 

presence of aquatic plants. The sand sank 

through the submerged weeds, and it sifted 

nicely through some dense patches of emergent vegetation with no sticking to leaves and 

stalks. Its advantages over liquid toxicants in 

weedy water were very apparent.

Among the abundant invertebrates in the 

ponds, the fresh-water shrimp and aquatic 

insects were unaffected by the antimycin. 

Rotifers, copepods, and cladocerans, however, were reduced in numbers in ponds 

treated with 3.12 and 10.4 p.p.b., but there 

was question whether the declines of the 

autumnal pulses were natural or caused 

wholly by the toxicant.

STUTTQUART, ARKANSAS

Two series of trials were conducted in 1965 

at the Bureau's Warmwater Fish Cultural 

Laboratory. The first, in March, included 

three pairs of one-quarter acre ponds which 

were stocked heavily with fish. We narrowed 

the range of concentrations further, and

treated the ponds with 5.0, 7.5, and 10.0 p.p.b. 

of antimycin in sand formulation. The lowest 

concentration eliminated 12 of the 14 species, 

including such important target fish as goldfish, carp, and green sunfish (table 8). There 

was a partial kill of channel catfish and 

warmouth. The concentrations of 7.5 and 10.0 

p.p.b. removed all species but channel catfish 

which suffered 3-percent mortalities at each 

concentration. An examination of the dead 

catfish disclosed that they were hosts to 

heavy infestations of Ichthyophthirius.

The second series of trials took place in 

December in a 20-acre reservoir and a 

0.25-acre pond. The fish in the reservoir 

were well-established populations, some of 

which were seined and stocked in the small 

pond. The waters were turbid, and colder and 

harder than during the March trials. Consequently, we elected to try a concentration of 

10 p.p.b. of antimycin in each body of water.

The experimental conditions were heightened because the reservoir had been drawn 

down to an average depth of about 2 feet, and 

the bottom was very soft mud. The small 

pond, on the other hand, ranges from 3 to 4 

feet in depth, and the bottom is relatively 

firm. A comparison of results with Fintrol-5 

would indicate whether there was significant 

loss of antimycin in the reservoir because 

the sand particles sank into the soft muck before releasing all of the toxicant.

Arrangements also were made to determine 

the minimum duration of exposure necessary 

to kill a species of fish. Live cages were

TABLE 8. --Effects of antimycin on fish at the Warmwater Fish Cultural Laboratory, March 1965

Species

Carp (Israeli), small.... 

Carp (Israeli), large....

Orangespotted sunfish. . . .

Size 

(inches)

4.9-9.1 

0.8-1.4 

3.0-8.5 

3.5-6.0 

23.0-26.0 

2.8-4.5 

5.5-13.0 

12.0-20.0 

12.0-18.0 

3.5-5.5 

2.5-7.0 

2.5-3.0 

4.0-6.5 

10.0-12.0

Number 

per 

pond

159-176 

237-321 

643-728 

530-688 

2-6 

302-511 

32-72 

76-99 

43-99 

14-26 

171-273 

39-59 

46-56 

28-40

Percent killed at

5.0 p.p.b.

100 

100 

100 

100 

100 

100 

100 

100 

2 

85 

100 

100 

100 

100

7.5 p.p.b.

100 

100 

100 

100 

100 

100 

100 

100 

3 

100 

100 

100 

100 

100

10.0 p.p.b.

100 

100 

100 

100 

100 

100 

100 

100 

3 

100 

100 

100 

100 

100
12 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

placed in the reservoir and each contained 

10 adult bigmouth buffalo. After a 2-, 3-, 4-, 

5- or 6-hour exposure to antimycin, the fish 

were transferred to an untreated pond. Subsequent observations revealed that the fish 

exposed to antimycin for 2 hours survived. 

Those fish exposed to the toxicant for 3 or 

more hours died.

Among the 19 species present in the reservoir, gizzard shad were the most sensitive to 

the toxicant, and all died in about 24 hours 

(table 9). The carp, buffalo, and most other 

species died within 72 hours. Survivors included paddlefish, catfishes, mosquitofish, 

and a few warmouth.

The toxicant produced a much quicker kill 

of fish in the 0.25-acre pond, with heavy mortalities occurring within 24 hours. All species 

except paddlefish and catfishes were dead at 

48 hours. All of the paddlefish, however, succumbed in about 72 hours in contrast with no 

kill of that species in the reservoir.

The trial demonstrated that antimycin 

works well in hard, cold, turbid water against 

scalefish without harm to 7 species of catfish. Among the scalefish, mosquitofish and 

warmouth were relatively tolerant to the 

toxicant.

The more rapid and complete kill of fish in 

the deeper, 0.25-acre pond was attributed to

a better release of toxicant than occurred in 

the reservoir. We believe that the sand particles sank into the soft bottom of the reservoir before releasing all of the antimycin. 

Thus, there is risk of an incomplete kill if the 

5-foot-release formulation is used in very 

shallow water over soft bottom.

VALENTINE, NEBRASKA

The first tests of antimycin in natural ponds 

occurred at Valentine NWR. Pond 1 has an 

average depth of only 1.8 feet and a relatively 

soft bottom. The target fish were wild, 

yearling carp and green sunfish. In addition, 

some northern pike and largemouth bass 

from a nearby lake were stocked prior to the 

trial (table 10). Pond 2 is an old dugout pond 

with an average depth of 4.2 feet, and at the 

time, it had overflowed its banks onto adjacent pasture. This pond receives heavy use 

by range cattle, and it is highly polluted by 

manure in the water and along the shore. It 

contained seven species of stocked fish, including large carp.

Both ponds were treated with the Fintrol-5 

formulation although the average depths were 

less than 5 feet. A concentration of 10 p.p.b. 

was selected because of the relatively high 

total alkalinity.

Five species of fish were eliminated from 

Pond 1 within 48 hours. They included the

TABLE 9. Effects of antimycin on fish at the Warmwater Fish Cultural Laboratory, December

1965

Species

Paddlefish..............

Goldfish. ...............

White catfish. ..........

Blue catfish. ...........

Yellow bullhead .........

Flathead catfish. .......

Orangespotted sunfish. . .

Size

(inches)

43.0-57.0

5.3-6.6

5.0-8.0

10.4-13.8

7.2-19.6

1.6-2.8

3.0-6.5

1.7-3.5 

2.5-4.2

5.3-16.0

3.2-9.7

Reservoir

Abundance

b d t

scarce

common

scarce

ere

common

(10 p.p. p.)

Percent 

killed

0

100

100

100

100

0

0

0

0

0

0

0

99

99

100

100

-] fin

100

1 r\r\

Pond (l

Abundance

scarce

--

D p.p.b.)

Percent 

killed

-] r\r\

-i nn

0

0

0

--
Gilderhus, Berger, and Lennon.- Field Trials of Antimycin A as a Fish Toxicant 13

TABLE 10.--Effects of antimycin on fish at Valentine NWR

Species

Yellow perch. ...........

Size

(inches)

14.0-24.0

10.0-26.0

1.8-2.9

2.0-8.2

6.0-15.0

7.2-8.5

5.5-9.0

Pond 1 (

Number 

present

6

197

0

42

0

169

56

1

90

10 p.p.b.)

Percent 

killed

100

100

0

100

100

100

100

Pond 2 (1

Number 

present

12

1,045

32,000

3

2 304

27

14

14

30

0 p.p.b.)

Percent 

killed

33

100

100

0

100

100

64

36

100

fathead minnows, carp, and green sunfish. 

There were partial kills of northern pike, 

largemouth bass, and black crappies ranging 

from 33 to 64 percent. Black bullheads survived.

The kill of fish was more rapid and complete in the deeper water of Pond 2, indicating a better release of the toxicant from the 

sand formulation. Most of the carp and other 

species were dead within 24 hours. We were 

unable to determine what influence the pollution by manure may have had on the activity 

of the toxicant.

There was no evidence of harm to aquatic 

insects in the ponds, and daphnia remained 

abundant, especially in Pond 2, after the 

treatment.

The principal highlights of the trial at 

Valentine were that antimycin is effective 

in alkaline water, in cattle-polluted 

water, and may eradicate carp and green 

sunfish at a concentration which permits 

survival of adult northern pike and largemouth bass.

SARATOGA, WYOMING

The Bureau's Division of Fish Hatcheries 

requested that we attempt to eradicate fish 

with antimycin in Lake Creek Lake at the 

Saratoga NFH. The 1.79-acre lake is springfed and serves as the water supply for the 

hatchery. The average depth is 3.25 feet, the 

maximum depth is 6 feet, and the water is 

clear and colorless. Thus, the lake afforded 

an excellent opportunity to further test the 

non-repellency of antimycin to fish and the 

performance of the sand formulation in

bottom springs. The hatchery's objective was 

to rid the lake of fish which might serve as 

vectors for diseases (table 11). Previous attempts with rotenone and chlorine had failed 

because the fish were repelled and fled into 

the springs to avoid contact.

The springs cause a complete exchange of 

water in the basin of the lake every 27 hours. 

Because of this, adequate exposure of fish to 

the toxicant was a critical consideration. 

Thus, we arranged to maintain at least 10 

p.p.b. of antimycin in the cold, relatively 

hard water for a minimum of 8 hours. This 

dose was achieved by making an initial application of 10 p.p.b. of Fintrol-5, followed 

by light applications at 6 and 8 hours later to 

compensate for spring inflows. Uniform distributions of the sand formulation over the 

surface were obtained by means of a seed 

spreader, and the sand grains sank readily 

into the large, bottom springs.

The water remained clear and colorless 

during and after the distribution of toxicant. 

The fish were easy to observe, and they exhibited no alarm or tendency to escape from 

the treated water. The first evidence of toxic 

effects was apparent 2 hours after the initial 

application. The dense schools of large, 

northern creek chubs began to break up. 

Otherwise normal in appearance, the chubs

TABLE 11. Effects of antimycin on fish at Saratoga NFH

Species

Brook trout, small

Brook trout, large

Fathead minnow. ....

Creek chub

Size 

(inches)

3.2-8.2

11.2-20.1

2.3-3.0

3.4-9.2

2.5

Number 

present

117

35

several hundred

1,152

10

Percent 

tilled at 

10 p.p.b.

100

100

100

100

100
14 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

seemed to lose their orientation with respect 

to schooling. None sought relief in springs. 

Most of them were dead within 24 hours, and 

all were dead within 48 hours.

Brook trout in the lake ranged from onethird ounce to 6.6 pounds, and we watched 

them carefully throughout the operation. They 

began to die after 3 hours of exposure, and 

all were dead within 24 hours. None had 

moved into the springs or tried to escape via 

the outlet. The responses of the numerous 

fathead minnows and the small numbers of 

Iowa darters were similar to those of the 

creek chubs and brook trout.

The antimycin on sand produced a complete 

kill of fish in Lake Creek Lake. The toxicant 

was flushed from the basin by spring flows 

within 40 hours, and it was detoxified effectively in the 3-c.f.s. outlet stream by a continual application of 1 p.p.m. of potassium 

permanganate for 40 hours.

WEST SALEM, WISCONSIN

Park Pond is a 4.78-acre, impounded oxbow 

of the La Crosse River in Veterans Memorial 

Park, and it is managed for trout on a putand-take basis. It is fed by bottom springs 

and an artesian well with cold, very hard 

water. Occasionally, however, the pond is inundated by the river and becomes contaminated with carp and panfish (table 12). When 

abundant, the invaders are considered a 

nuisance, and attempts are made periodically 

to reduce or eliminate them.

TABLE 12. Effects of antimycin on fish in Veterans Memorial 

Park Pond

Species Size 

(inches)

9.6-11.3

7.8-13.0

4 0 av

3.9-10.0

16.0-27.0

4.9-6.1

3.3 av.

7

rt

4.1-9.0

3.6

2.0-4.1

2.0-3.9

Number 

present

6

54

3

44

49

1

100+

2

1

19

3

Percent 

killed at 

10 p.p.b.

i nn

i nn

100

100

100

100

100

100

0

0

100

100

100

We cooperated with the Wisconsin Conservation Department to test antimycin in the 

Fintrol-5 forumlation in Park Pond against 

the numerous carp, minnows, ans stunted pan 

fish. The trial also afforded an opportunity to 

observe any effects of the toxicant on a large 

flock of semi-tame mallards on the pond.

The treatment consisted of 10 p.p.b. of 

antimycin and the sand formulation was distributed by seed spreader from a boat. Rainbow trout, brown trout, and northern pike 

were the most sensitive, and many were dead 

within 5 hours. Large numbers of carp and 

tens of thousands of fathead minnows died 

within 12 hours. The kill of scale fish was 

complete within 48 hours, and only catfishes 

survived.

The mallards gorged themselves on dead 

fathead minnows and suffered no ill effects 

from the toxicant or the poisoned fish. The 

toxicant degraded in 6 days.

Nine days after the application of antimycin, Park Pond was treated with 5 p.p.m. 

of rotenone to check on the kill of carp and 

other fish. The treatment confirmed that no 

scale fish survived the antimycin, and only 

bullheads and a few channel catfish had remained.

MADISON, WISCONSIN

Lake Katrine, a 30-acre natural lake with 

warm, soft water, was selected for trials of 

antimycin against carp eggs in the spring and 

for total eradication of carp and fathead minnows in the fall.

Two days after the commencement of 

spawning by carp, a 2.7-acre bay was treated 

with 4 p.p.b. of antimycin in Fintrol-5. It, 

and an adjacent bay serving as a control, contained hundreds of thousands of fertilized 

carp eggs. Within 48 hours, the treated eggs 

had turned white and opaque, and many were 

covered with fungus. In contrast, the untreated 

eggs were alive and reaching the eyed stage. 

At 96 hours, most of the treated eggs had 

disintegrated, and extensive sampling failed 

to disclose any live eggs or fry. The eggs in 

the control bay, however, were hatching normally and fry were abundant.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 15

During the course of the test, some eggs 

from the treated and untreated bays were 

taken to the laboratory. Only 2 percent of the 

treated eggs hatched, and the fry died within 

24 hours. Ninety-seven percent of the untreated eggs hatched, and the fry lived for 

several weeks until discarded. We concluded 

that antimycin has potential for killing the 

spawn of carp in the field.

Several months later, all of Lake Katrine 

was treated with 7.5 p.p.b. of antimycin in 

Fintrol-5 to kill carp and fathead minnows. 

The distribution was made in an hour by seed 

spreaders mounted on two boats. A heavy kill 

of fish was apparent within 24 hours, and 

sampling with large seines two weeks later 

indicated that the carp and fatheads had been 

eliminated.

OXFORD, WISCONSIN

We were asked by the Wisconsin Conservation Department to try antimycin on the carp 

in Parker Lake, a 63-acre natural body of 

water with a maximum depth of 40 feet. The 

problem was the abundance of young-of-theyear carp which followed an incomplete 

reclamation with toxaphene the previous year 

(table 13).

The cold, hard water was treated with 10 

p.p.b. of antimycin in October. Fintrol-5 was 

applied in the littoral zone, 0 to 10 feet deep. 

Fintrol-15 and Fintrol-30 were applied to 

areas of the lake ranging from 11 to 20 feet 

deep and 21 to 40 feet deep, respectively. 

Some Fintrol-Liquid was sprayed on very 

shallow areas along the shore.

The water in the lake was clear and permitted good observation of fish. Thousands of 

carp and some rainbow trout and bluegills

TABLE 13.--Effects of antimycin on fish in Parker Lake

Species Size

( inches )

13-18

2-12

3-7

2-5

3-9

Abundance

Percent 

killed at 

10 p.p.b.

100

100

T nn

~\ <~\r\

100

were dead within 24 hours. Although we estimated that 60 percent of the fish were dead 

within 48 hours, the heavy mortality continued 

for 2 weeks. One month after treatment, one 

fingerling bluegill was caught in a fyke net. 

Intensive netting during the following spring 

failed to capture any fish, and we concluded 

that the antimycin had eradicated carp and 

other species.

The good performance of the deeper water 

formulations, Fintrol-15 and Fintrol-30, 

justified their further development for management use.

Trials in Streams

VIROQUA, WISCONSIN

The Wisconsin Conservation Department 

wanted to rid Sidie Hollow Creek of rough 

fish before filling a new impoundment which 

is to be managed for trout. The job offered an 

opportunity to test antimycin against a variety 

of fish in the cold, hard water of a small trout 

stream.

We formulated the liquid toxicant at the 

site by dissolving technical-grade antimycin 

in ethanol. By means of drip stations, a concentration of 15 p.p.b. of antimycin was maintained for 5 hours at any given site on the 

stream.

The concentration was too high, and it produced rapid results. Some fish exhibited distress within an hour. Most species were in 

distress within 3 hours, and mortality of fish 

was nearly complete in 12 hours (table 14). 

The bolt of toxicant moving downstream did 

not repel fish, and there was no evidence of 

fish fleeing ahead of the bolt. Rather, fish 

tended to drift involuntarily downstream when 

they became distressed and unable to maintain their positions in the current.

A post-treatment survey with electrofishing 

gear demonstrated that the 11 species of fish 

had been exterminated. This success led to 

further development and testing of FintrolLiquid for field application.
16 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

TABLE 14. Effects of antimycin on fish in streams

Species

American brook lamprey. .

White sucker. ...........

Bluegill....... .........

Sidle Hollow Creek 

15 p.p.b. -5 hrs.

Abundance

scarce 

scarce

common

abundant 

common 

common 

common 

scarce 

common

common 

scarce

Percent 

killed

100 

100

100

100 

100 

100 

100 

100 

100

100 

100

Mullet River 

7.5 p.p.b.-8 hrs.

Abundance

scarce

common 

scarce

abundant

common 

common

scarce 

scarce

scarce 

scarce 

scarce

common

Percent 

killed

100

100 

100

99+

100 

100

100

100

100 

100 

100

100

Rathbone Creek 

7.5 p.p.b.-8 hrs.

Abundance

common

common 

common

common 

common

common

Percent 

killed

100

100

0

99+ 

99+

100

Westfield Creek 

10 p.p.b.-lO hrs.

Abundance

common 

scarce

abundant 

abundant 

common 

abundant

common 

abundant

scarce

scarce 

common 

common

common 

common 

common

Percent 

killed

50 

100

100 

100 

100 

100

100 

100

100

100 

100 

100

100 

100 

100

Waterloo Creek 

10 p.p.b.-lO hrs.

Abundance

scarce 

abundant

abundant

Percent 

killed

100 

100

100

PLYMOUTH, WISCONSIN

The sport fishery on a portion of the Mullet 

River had deteriorated because of an abundance of carp, suckers, green sunfish, and 

other non-game fish. We cooperated with the 

Wisconsin Conservation Department in reclaiming a 2.5-mile portion of the river, including two small impoundments, with 

antimycin. Prior to the treatment, one impoundment was drained to stream bed, and 

the other was lowered to a pool containing 

3 acre-feet of water.

The test section was characterized by a 

slow flow of warm, very hard water. The 

speed of flow was measured between application stations by use of fluorescein dye. Estimates were made on the stretchout and dilution of a toxicant between stations.

A liquid formulation of antimycin in acetone 

was prepared at the site. We installed drip 

stations and tried to maintain a concentration 

of 7.5 p.p.b. for a minimum of 8 hours at any 

given point along the stream. The 3 acre-feet 

of impoundment were treated with Fintrol-5 

coincident with the arrival of the flowing bolt 

of toxicant. When the toxicant reached the 

downstream dam, both dams were closed. The

refilling of the impoundments thus allowed 

dilution and degradation of the toxicant.

Creek chubs, white suckers, green sunfish, 

and small black crappies began to die after 2 

hours of exposure. Carp were distressed 

within 2 to 5 hours near sites where the 

toxicant was introduced. Many adult carp 

moved into shallow water and took up to 72 

hours to die. Nine tons of carp were collected 

from less than 2 miles of the stream.

An electrofishing survey made 5 days after 

the reclamation turned up seven carp, two of 

which appeared to be in distress from antimycin. We estimated that more than 99 percent of the carp and 100 percent of the other 

fish had been eliminated by the toxicant 

(table 14).

The relatively slow and imcomplete kill of 

carp indicated that the concentration of toxicant was marginal. We surmise that the loss 

of toxicant between fortifying stations was 

greater than estimated. Thus, the concentration of antimycin was less than 7.5 p.p.b. in 

places. This error points up the necessity of 

accurately measuring the stretchout and dilution of a toxicant in streams and fortifying as 

indicated to maintain an effective concentration along the entire course of target water.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 17

CATARACT, WISCONSIN

Rathbone Creek provided a different experimental situation than the previous 

streams. It is a small, soft water, trout 

stream flowing through an infertile sand 

plain. The object of the reclamation was to 

reduce or eliminate white suckers to enhance 

intensive management of the stream for brook 

trout.

The 6 miles of test water were characterized by sand bottom and boggy shoreline. Two 

ponds were included; the upper one was 

drained to stream bed; and the lower pond, at 

the downstream limit of test water, was partially drained to a pool of 12 acre-feet. The 

salt-resistivity technique was used to estimate the amounts of toxicant needed at 

several stations to maintain a concentration 

of 7.5 p.p.b. of antimycin for a minimum of 

8 hours at any given point in the stream. The 

pool in the lower pond was treated with 

Fintrol-5 coincident with the arrival of the 

bolt of toxicant in the stream. The selection 

of concentration and duration of exposure was 

based on the fact that the water temperature 

was only 5°C.

Dead and dying fish appeared in the following order after the treatment commenced; 

brook trout in 2 to 3 hours, white suckers in 

3 to 6 hours, brook sticklebacks and minnows 

in 5 to 6 hours (table 14). All rainbow trout 

and fathead minnows in live cages throughout 

the treatment area were dead within 24 hours. 

The results, however, were assessed by 

electrofishing several days later. One fingerling white sucker, two brook sticklebacks, 

and numerous mudminnows were collected in 

four sample areas totalling 0.75 miles of 

stream.

An incomplete distribution of antimycin in 

the numerous spring seeps and backwaters 

may have enabled the sucker and sticklebacks 

to survive. It was apparent, nevertheless, 

that more than 99 percent of each species 

succumbed to the toxicant. On the other hand, 

the mudminnows were unaffected by the treatment. A subsequent bioassay of antimycin

against mudminnows from Rathbone Creek 

showed that an 8-hour exposure to 15 p.p.b. 

was necessary to kill them. Since mudminnows were eliminated by 10 p.p.b. of antimycin in other field trials, we concluded that 

the Rathbone strain was relatively resistant.

WESTFIELD, WISCONSIN

The experimental reclamation of a 3-mile 

portion of Westfield Creek was an attempt to 

eradicate the abundant carp and suckers 

(table 14). Power dams are located at the 

upper and lower ends of the test portion, and 

the volume of stream flow ranged from 

8 c.f.s. at the upper end to 22 c.f.s. at the 

lower end. The pool of the lower pond was 

drained to stream channel. Rhodamine-B dye 

was used to estimate the stretchout and dilution of a toxicant.

Because of the relatively high pH and total 

hardness of the water, we elected to apply 

10 p.p.b. of antimycin in Fintrol-Liquid 

formulation and to maintain the concentration 

for at least 10 hours. Most of the toxicant was 

metered into the stream, but two crews in 

boats endeavored to spray antimycin on 

backwaters and pockets off the mainstream.

The target carp and suckers began to exhibit distress in about 8 hours, and many 

were observed swimming slowly with the current. In the meantime, large numbers of 

creek chubs, other minnows, bluegills, largemouth bass, and darters were drifting helplessly downstream. We estimated that 98 

percent of the fish in the stream were dead 

at 24 hours, and all were dead at 96 hours. 

Approximately 23,000 pounds of fish were 

collected and carp comprised 95 percent by 

weight.

An electrofishing survey a week after the 

reclamation resulted in the capture of one 

brook stickleback and a few small minnows. 

We believe that these specimens had passed 

through the upper power dam after the treatment. The target species, carp and suckers, 

were absent.
18 Investigations in Fish Control 27: Bureau of Sport Fisheries and Wildlife

MADISON, WISCONSIN

Waterloo Creek was selected to test the 

effects of a brief exposure to antimycin on 

carp. A 1-mile portion of the small, very 

slow stream was blocked off by anchored 

seines, and observations on flow characteristics were made with rhodamine-B dye. The 

experimental nature of the reclamation was 

accented by the fact that the water contained 

a heavy load of effluent from a municipal, 

sewage-treatment plant.

A concentration of 10 p.p.b. of antimycin 

was maintained for 5 hours in the test portion 

of stream. Fish reacted rapidly, and carp and 

white suckers began to die within 2 hours. 

Within 24 hours, thousands of dead carp and 

suckers and a few northern pike littered the 

shores, and we found no survivors (table 14). 

No other species were present.

Although the water at 25° C. was warmer 

than in any of the previous field trials, we 

believe that it was not the sole cause for the 

rapidly toxic action of the antimycin. The 

sewage effluent may have enhanced the activity of the toxicant or reduced the resistance 

of the fish.

The dose of antimycin at 10 p.p.b. for 5 

hours was considered very effective on carp 

in this situation.

Effects on Non-target Animals

Every opportunity was taken to observe any 

effects of antimycin on invertebrate and 

vertebrate animals. In most situations, the 

fish-killing concentrations of antimycin had 

no significant effects on invertebrates (table 

15). The first of two exceptions occurred at 

Cape Vincent NFH when autumn pulses of 

rotifers, water fleas, and copepods were 

greatly reduced in ponds treated with 3 and 

10 p.p.b. of antimycin. Although we are inclined to believe that the toxicant contributed 

to the loss of zooplankton, the season's first 

killing frosts at the time of the experiment 

may have played some part in the declines.

TABUS 15.--Effects of antlmyoin on invertebrates

Technical 

name

Rotatoria .

Tubificidae....

Cladocera. .....

Daphnla

Ceriodaphnia

Bosmina

Copepoda... ....

Ostracoda. .....

Anphipoda ......

Decapoda. ......

Ephemeroptera . .

Odonata. .......

Hemiptera

Corixidae. .. .

Notonectidae.

Diptera

Tendipedidae .

Common name

Rotifers

Aquatic earthworms

Water fleas

Copepods

Seed shrimps

Scuds

Crawfish

Freshwater shrimp

Mayflies

Damselflies

Water boatmen

Backswimmers

Midge

Effect

99 percent kill

no effect

99 percent kill

99 percent kill

no effect

99 percent kill

no effect

99 percent kill

no effect

Partial mortality

no effect

no effect

Partial mortality

no effect

no effect

no effect

no effect

no effect

Concentration 

of antimycin 

(p-P-b.)

3.12

3.12

3.12

10.40

3.12

10.40

3.12

3.12

10.40

4.0

1.04

10.0

10.0

10.4

10,0

10.4

10.4

12.0

TABU) 16. Effect of antimycin on vertebrates exposed to treated water 

or which fed on fish killed by antimycin

Technical name

Ambystomidae .....

Tadpoles 

Adults

Chelydridae...... 

Colubridae. ......

Common name

Mole salamanders

Turtles 

Water snake

Effect

no effect

no effect 

no effect

no effect 

no effect 

no effect

no effect

Cone entrat ion 

of antimycin 

(p.p.b.)

10.0

10.0 

10.4

10.0 

10.0 

10.4

10.0

10.0

10.4

10.0

The second exception involved the freshwater shrimp at Saratoga NFH. Most of the 

shrimp in the pond were exposed to 10 p.p.b. 

of antimycin without harm. Some, however, 

were exposed to temporarily higher concentrations in springs, and they perished.

Vertebrates exposed to antimycin during 

the field trials have included frogs, salamanders, water snakes, turtles, waterfowl, 

and wading birds (table 16). Many were observed eating antimycin-killed fish. We saw 

no evidence of mortality or harm among these 

animals.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 19

DISCUSSION

Antimycin proved to be an effective toxicant 

for many species of fish in lakes and streams. 

We endeavored to estimate a minimum effective concentration for the target species in 

each trial, and as might be expected, we were 

too high with some concentrations and too 

low with others. The results, however, permit some generalizations. For example, less 

toxicant may be required in soft water then 

in hard water; less is required in warm 

water than in cold water; and less is required in water with low pH than high pH. 

Prime target species such as carp and suckers can be eliminated by concentrations of 3 

to 10 p.p.b. of antimycin, depending on water 

quality and temperature. Goldfish, bowfin, and 

gar are more resistant and may require considerably more than 10 p.p.b. for control. 

Bullheads and catfish are the most resistant, 

and they were relatively unharmed by the 

concentrations used in the trials. The differences in sensitivity of various species to 

antimycin are leading to tests of the chemical 

as a selective toxicant.

The reactions of fish to antimycin are slow 

and unspectacular. The first stages of distress are characterized by the fish losing 

their orientation and swimming slowly along 

the shore or near the surface. They have 

progressively less reaction to stimuli until 

they can be picked up easily by hand. In 

streams, they drift involuntarily downstream, 

feebly trying to maintain their position. They 

soon lose their equilibrium and turn over on 

their sides or backs. The final stages are 

characterized by short alternate periods of 

quiescence and feeble, erratic swimming. Infrequently, a fish will thrash about on the 

surface for short periods of time.

The most sensitive species such as trout 

and yellow perch usually show symptoms of 

distress in a few hours whereas more resistant ones such as largemouth bass and 

carp may not be affected for 10 to 24 hours. 

Mortality of fish is usually complete within 

72 to 96 hours after treatment.

Our trials to date have indicated that the 

effects of antimycin are irreversible. Once

fish exhibit symptoms of distress, they die, 

even if placed in fresh water. In some 

streams where the chemical moved on past 

the fish, they lived for many hours in fresh 

water before dying.

In no case did we see fish exhibit an avoidance reaction to antimycin. They do not seek 

out springs or untreated areas. The lack of 

repellency is a significant advantage in 

spring-fed lakes and in streams.

The formulations of antimycin on sand are 

effective, easy to apply, and safe to handle. 

They are almost dust-free when broadcast 

by hand or by means of mechanical seed 

spreaders. Fintrol-5 was registered in the 

United States and Canada, largely as a result 

of the trials reported here. The formulations 

for deeper water, Fintrol-15 and Fintrol-30, 

are to be developed further and registered.

The results in one pond at Stuttgart, 

Arkansas, and another at Valentine, Nebraska, 

demonstrated that Fintrol-5 should not be 

used in water less than 3 feet deep when the 

bottom is very soft. Under such conditions, 

the sand grains may sink into the mud before 

releasing all of the antimycin. The concentration of toxicant in the water may be less, 

therefore, than desired. A liquid formulation 

would be better in these circumstances.

The liquid formulation of antimycin performed well in shallow waters of ponds and 

marshes and in streams. It can be sprayed 

over the water or dispensed into the water by 

a metering pump. A surfactant in the formulation aids dispersion in the water. We are 

confident that Fintrol-Liquid will be registered by the U.S. Department of Agriculture 

in the near future.

The evaluation of a candidate fish toxicant 

in the field is difficult because the techniques 

involved in the reclamation of lakes or 

streams are primitive, inexact, or unproven. 

The volumes of lakes are more often estimated 

than measured. Estimates on the volume 

of flow and velocity in streams are frequently and seriously inaccurate. The saltresistivity and dye-fluorometer techniques
20 Investigations in Fish Control 27; Bureau of Sport Fisheries and Wildlife

for detecting the flow characteristics of 

streams need further development to make 

them more widely applicable and useful. The 

influences of water chemistry and temperature on toxicants are not well understood, and 

additional research is required. The means of 

dispensing toxicants in various formulations 

need improvement. Also, more attention must 

be given to defining the best ways for measuring pre- and post-treatment populations of 

fish to improve the assessment of reclamations. And, field techniques must be developed 

for detecting and measuring concentrations 

of toxicants in lakes and streams.

The deficiencies in the technology of 

reclamation have caused fishery managers to 

resort to overdoses of toxicants to obtain 

satisfactory results. This is a poor and 

hazardous solution to the problem, and it is 

unacceptable to authorities who regulate 

pesticides.

In retrospect, the outstanding lesson derived from the field trails was that lakeside 

or streamside bioassays of a toxicant should 

be made against target species immediately 

prior to a reclamation. Preferrably, the fish 

and the water in the bioassays are taken from 

the target lake or stream. Also, the temperatures of the bioassays and the target water 

should be approximately the same. Moreover, 

several concentrations of the toxicant which 

bracket the proposed concentration should be 

tested. The results of such bioassays should 

indicate the concentration and formulation of 

toxicant which are most likely to produce the 

desired results in the reclamation; the presence of favorable influences of water quality 

or temperature; and the presence of unusually sensitive or resistant strains of 

target fish.

The routine use of lakeside or streamside 

bioassays would benefit efficiency and economy because the number of imperfect 

reclamations would be reduced or the overdosing of target waters would be decreased. 

The idea of on site bioassays is not new. The 

procedure was recommended, for example, 

in reclaiming streams by Lennon and Parker

(1959) and in anesthetizing fish in the field by 

Schoettger and Julin (1967).

CONCLUSIONS

1. Antimycin is effective as a fish toxicant 

in standing and flowing waters.

2. The effective concentration for most 

species, including such prime target 

species as carp, suckers, and green sunfish, is 10 p.p.b. or less in waters below 

pH 8.5. Catfishes are not vulnerable, 

however, to concentrations which are 

lethal to scale fishes.

3. Fish eggs are killed by the same concentrations used to control free-swimming 

fish.

4. Antimycin degrades rapidly, especially 

under alkaline conditions, and most 

waters can be restocked with fish within 

2 weeks after treatment.

5. Antimycin in water can be detoxified by 

1 p.p.m. or less of potassium permanganate.

6. The effects of antimycin in fish appear to 

be irreversible.

7. The toxicant in liquid or sand formulations does not repel fish.

8. The concentration of toxicant to be used 

in a reclamation should be determined by 

preliminary bioassays on site against 

target fish in target water.

9. Antimycin in fish-killing concentrations 

is largely specific to fish and causes no 

harm to most of the other aquatic animals.

10. Concentrations greater than 10 p.p.b. are 

required in waters of high pH and 

alkalinity.
Gilderhus, Berger, and Lennon: Field Trials of Antimycin A as a Fish Toxicant 21

REFERENCES

Anderson, Gaylord A.

1962. Three portable feeders for metering chemical into streams for control of sea lamprey. 

The Progressive Fish-Culturist, vol. 24, No. 4, 

p. 190-192.

Berger, Bernard L., Robert E. Lennon, and James W. 

Hogan

1969. Investigations in Fish Control: 26. 

Laboratory studies on antimycin A as a fish 

toxicant. U.S. Bureau of Sport Fisheries and 

Wildlife.

Buchanan, Thomas J.

1964. Time of travel of soluble contaminants in 

streams. Journal of the Sanitary Engineering 

Division, American Society of Civil Engineers, 

vol. 90, No. SA3, Proceedings Paper 3932, 

p. 1-12.

Burress, Ralph M.

1968. Antimycin for controlling sunfish populations 

in ponds. Farm Pond Harvest, vol. 1, No. 2, 

p. 11-12, 22.

Burress, Ralph M., and Charles W. Luhning

1969a. Investigations in Fish Control: 27. Field 

trials of antimycin as a selective toxicant in 

channel catfish ponds. U.S. Bureau of Sport 

Fisheries and Wildlife.

1969b. Investigations in Fish Control: 28. Use of 

antimycin for selective thinning of sunfish populations in ponds. U.S. Bureau of Sport Fisheries 

and Wildlife.

Herr, F., E. Greselin, and C. Chappel

1967. Toxicology studies of antimycin, a fish 

eradicant. Transactions of the American 

Fisheries Society, vol. 96, No. 3, p. 320-326.

Lennon, Robert E.

1959. The electrical resistivity meter in fishery 

investigations. U.S. Bureau of Sport Fisheries 

and Wildlife, Special Scientific Report 

Fisheries No. 287. 13 p.

Lennon, Robert E.

1966. Antimycin - a new fishery tool. Wisconsin 

Conservation Bulletin, vol. 31, No. 2, p. 4-5.

Lennon, Robert E., and Philip S. Parker

1959. Reclamation of Indian and Abrams creeks in 

Great Smoky Mountains National Park. U.S. 

Bureau of Sport Fisheries and Wildlife, Special 

Scientific Report Fisheries No. 306. 22 p.

Lennon, Robert E., Bernard L. Berger, and Philip A. 

Gilderhus

1967. A powered spreader for antimycin. The 

Progressive Fish-Culturist, vol. 29, No, 2, 

p. 110-113.

Loeb, H. A.

1964. Some notes concerning the toxicity of 

antimycin A to carp and other fish. New York 

Fish and Game Journal, vol. 11, p. 160-161.

Powers, James E., and Anne LaBastille Bowes 

1967. Elimination of fish in the Giant Grebe 

Refuge, Lake Atitlan, Guatemala, using the fish 

toxicant, antimycin. Transactions of the American Fisheries Society, vol. 96, No. 2, p. 210-213.

Powers, James E., and Edward Schneberger

1967. Antimycin: promising in carp control. 

Wisconsin Conservation Bulletin, vol. 32, No. 2, 

p. 14.

Radonski, Gilbert C.

1967. Antimycin: useful in perch control?

Wisconsin Conservation Bulletin, vol. 32, No. 2, 

p. 15-16.

Schoettger, Richard A., and Arnold M. Julin 

1967. Investigations in Fish Control: 13. 

Efficacy of MS-222 as an anesthetic on four 

salmonids. U.S. Bureau of Sport Fisheries and 

Wildlife, Resource Publication 19. 15 p.

Vezina, Claude

1967. Antimycin A, a teleocidal antibiotic. 

Antimicrobial Agents and Chemotherapy-1966. 

American Society for Microbiology, p. 757-766.

Walker, Charles R., Robert E. Lennon, and 

Bernard L. Berger

1964. Investigations in Fish Control: 2. Preliminary observations on the toxicity of antimycin A to fish and other aquatic animals. U.S. 

Bureau of Sport Fisheries and Wildlife, Circular 

186. 18 p.
INVESTIGATIONS IN FISH CONTROL

28. Use of Antimycin

for Selective Thinning of 

Sunf ish Populations in Ponds

By Ralph M. Burress, Fishery Biologist and

Charles W. Luhning, Physical Science Technician

United States Department of the Interior

Fish and Wildlife Service

Bureau of Sport Fisheries and Wildlife

Washington, D.C. . February 1969
CONTENTS

Page

Abstract. ....................................... 3

Methods and materials .............................. 4

Ponds and fish populations......................... 4

Application of toxicant. ........................... 5

Treatment evaluation ............................ 5

Results. ........................................ 5

Henry Pond. .................................. 5

Todd Pond. ................................... 5

Slaughter Pond. ................................ 7

Hill Pond .................................... 7

Reynolds Pond. ................................ 7

Diggers Pond. ................................. 7

Discussion ...................................... 7

Summary ....................................... 9

References ...................................... 9
USE OF ANTIMYCIN FOR SELECTIVE THINNING 

OF SUNFISH POPULATIONS IN PONDS

By Ralph M. Burress, Fishery Biologist 

and Charles W. Luhning, Physical Science Technician

Bureau of Sport Fisheries and Wildlife

Southeastern Fish Control Laboratory

Warm Springs, Georgia

ABSTRACT. Selective removal of bluegills, redear sunfish, and redbreast sunfish was accomplished in six soft-water ponds in west central 

Georgia by applications of 0.4, 0.6, 0.8, and 1.0 parts per billion (p.p.b.) 

of antimycin in the Fintrol-5 formulation. Successful treatments were 

made during winter, spring, and late summer at water temperatures 

ranging from 46° to 75° F. and under a wide variety of weather conditions. The amount of toxicant applied per treatment was calculated according to total pond volume. The 0.4-p.p.b. treatment made at 75° F. 

removed 2.9 pounds per acre of largemouth bass less than 6 inches long 

and 69 pounds per acre of all sizes of sunfishes. The 0.6 p.p.b. applied at 

47° F. reduced the numbers of bluegills less than 4 inches in length by 

about half with very little effect on largemouth bass or larger bluegills. 

Bass, bluegills, and redear sunfish which survived multiple exposures to 

antimycin in concentrations up to 1.0 p.p.b. were able to reproduce normally. The toxicant is easy to apply, and costs only $0.64 per acre-foot at 

the 0.4-p.p.b. concentration.

During the past 15 years, fishery managers 

have made increasing use of the technique of 

selectively thinning overcrowded sunfish 

populations in small impoundments by applying rotenone in shallow areas (Swingle, 

Prather, and Lawrence, 1953; Hooper and 

Crance, 1960; Bennett, 1960; Thomaston, 

1962). Although the technique is fairly effective under favorable circumstances, its usefulness is rather seriously limited by weather 

conditions, water temperatures, and other uncontrollable factors which strongly influence 

fish behavior and distribution within the impoundment. Because of these limitations, 

there is only a relatively short time each year 

when the method can be employed. The results 

of this study indicate that light applications of 

antimycin can be used to accomplish selective

thinning of sunfish populations over a much 

longer period of time each year and under a 

much wider range of weather and water conditions than previously has been possible.

The purpose of the tests was threefold: 

(1) To determine what segments of the fish 

population would be eliminated by different 

concentrations of antimycin, (2) to measure 

the effects of given concentrations of antimycin under different experimental conditions, and (3) to learn whether fish exposed to 

sublethal concentrations of antimycin would 

reproduce normally.

The tests were conducted from December 

1966 to September 1967 in six privately owned 

ponds which contained unbalanced fish populations. The ponds are in the vicinity of Warm
Investigations in Fish Control 28: Bureau of Sport Fisheries and Wildlife

Springs, Ga., and they were referred to us by 

the Work Unit Conservationist, Pine Mountain 

Soil Conservation District.

Our sincere thanks are expressed to the 

following whose cooperation made this study 

possible; Mr. P. A. Gantt, whose help in obtaining the use of ponds for experimental purposes was invaluable; Messrs. W. A. Diggers, 

Joe Henry, Render Hill, J. F. Reynolds, 

W. S. Slaughter, and R. A. Todd, owners of 

the ponds; Wisconsin Alumni Research Foundation, owner of antimycin; and Ayerst Laboratories, New York, producer of antimycin.

METHODS AND MATERIALS

Surface areas of most larger ponds were 

determined by measuring aerial photographs, 

and volumes were estimated from soundings. 

Areas and volumes of the remaining ponds 

were calculated from field-drawn contour 

maps. The ponds were treated with one or 

more of the following concentrations of antimycin: 0.4, 0.6, 0.8, and 1.0 parts per billion 

(p.p.b.). Not more than three concentrations 

were used in a single pond, and treatments 

were made at intervals of not less than 1 

month. Intensive efforts to recover dead fish 

were continued from 4 to 22 days after each 

application depending upon water temperatures. Surface water temperatures were taken 

each day, and average values were calculated 

for the time during which fish were collected. 

Henry Pond contained a dense growth of cattails and supported such a heavy plankton 

bloom that it was lowered to about half its 

original depth prior to the first treatment to

enhance recovery of dead fish. All other ponds 

were overflowing when treated. Final evaluations of the effects of treatment were made in 

different ways, as explained below.

PONDS AND FISH POPULATIONS

The ponds contained soft water, were spring 

fed, and were relatively infertile (table 1). 

They ranged in size from 0.69 to 9.80 acres, 

were from 3 to 6 feet in average depth, and 

overflowed at rates from 3.5 to 106.0 gallons 

per mintue (g.p.m.).

Henry Pond contained a dense stand of cattail (Typha latifolia). and it was lowered about 

3 feet prior to the first treatment to facilitate 

recovery of fish. Only sparse growths of 

rooted aquatic vegetation were present in the 

other ponds.

Each pond contained largemouth bass 

(Micropterus salmoides) and overcrowded 

populations of one or more of the following 

species of sunfishes: bluegill (Lepomis 

macrochirus). redear sunfish (Lepomis 

microlophus). and white crappie (Pomoxis 

annularis). Other species encountered included redbreast sunfish (Lepomis auritus). 

orange spotted sunfish (Lepomis humilis), 

golden shiner (Notemigonus crysoleucas), 

brown bullhead (Ictalurus nebulosus), channel 

catfish (Ictalurus punctatus). and mosquitofish (Gambusia affinis), (table 2). All of the 

ponds except Reynolds Pond were to be 

drained eventually and converted to production 

of channel catfish, hence their fish populations 

were expendable.

TABLE 1. Some physical and chemical characteristics of six ponds treated with antimycin

Characteristics

Dates of treatment ....

Surface area (acres)..

Average depth ( feet ) . .

Volume (acre-feet)....

Overflow rate (G.P.M.)

Secchi disk. ...........

transparency (inches)

Surface temperature (°F.)

Total hardness (p. p.m.)

Total alkalinity (p. p.m. )

pH.....................

Henry Pond1

12/05/66 1/13/67 3/08/67

0.16 0.16 0.77

3.0 3.0 4.0

0.48 0.48 3.08

5.3 5.3 5.3

10 13 18

47 50 61

8.0 10.0 10.0

11.0 11.0 9.0

7.32 6.87 6.90

Todd Pond

12/08/66 1/09/67 3/07/67

0.69

5.0

3.45

3.6

60 60 60

52 46 57

12.0 12.0 15.0

12.0 12.0 12.0

7.09 7.09 6.90

Hill Pond

1/31/67 3/07/67

2.25

5.0

11.25

3.5

36 17

56 59

7.0 8.0

7.5 7.5

6.98 6.75

Slaughter 

Pond

3/13/67

2.24

6.0

13.44

6.6

18

64

8.0

8.0

6.55

Reynolds 

Pond

3/27/67

9.80

4.1

40.18

5.5

10

68

8.0

8.0

6.84

Biggers 

Pond

9/i:i/67

2.48

4.7

11.67

106.0

12

75

10.0

14.0

7.20

1 Pond area, depth, and volume increased as pond filled during period of treatment.
Burress and Luhning: Antimycin for Thinning Sunfish Populations

TABLE 2. Species of fish indicated by X were present in six ponds treated 

with antimycin

Species

Redbreast sunfish 

Orangespotted sunfish. .

Henry 

Pond

--

Todd 

Pond

-

y^

Hill 

Pond

J£

--

Slaughter 

Pond

T£

X

Reynolds 

Pond

X

y^

-

X

X

Biggers

Pond

X

X

X

X 

X 

X

T£

APPLICATION OF TOXICANT

In each case, antimycin in the Fintrol-5 

formulation was used. The toxicant, which 

was supplied by Ayerst Laboratories, was a 

1-percent formulation of antimycin coated on 

sand with Carbowax. The amounts of toxicant 

applied per treatment ranged from 0.8 ounces 

to 6.56 pounds, and were based on pond volume without regard to maximum depth or 

amount of overflow. A boat was used to distribute the toxicant from a beaker, a handoperated seed spreader, or a powered 

spreader such as described by Lennon, 

Berger, and Gilderhus (1967), depending upon 

the size of the area to be treated. We were 

able to make applications of antimycin without regard to the time of day since diurnal 

elevations in pH were small in each pond.

TREATMENT EVALUATION

Henry and Todd ponds were drained as 

much as possible soon after the last application of antimycin, and the remaining fish 

were recovered by seining and heavier application of toxicant. The percentages of the 

populations recovered after each application 

were calculated, and comparisons of relative 

effectiveness of each treatment made.

Draining of Hill and Slaughter ponds was 

postponed until September, so that reproductive success of the treated fish could be 

evaluated. Upon draining, the fish were recovered, processed, and the effect of the 

treatment was assessed.

Reynolds Pond could not be drained. The 

effectiveness of its treatment was judged by 

the numbers and sizes of bass and sunfishes

killed and collected within 5 days. Since the 

pond was large, a representative sample of 

small fish was picked up along segments of 

shoreline amounting to about one-fourth of 

the total. All larger bass and sunfish were 

picked up around the entire pond margin. The 

pond was seined 5 months later, in late August 

and early September, to measure reproductive 

success of treated fish and to check on the 

general condition of the fish population.

Biggers Pond will not be drained until further tests are made, hence the results of 

treatment were evaluated simply by comparing the numbers and sizes of bass and sunfishes recovered.

RESULTS

Because there were such wide variations in 

pond characteristics, dates and conditions of 

treatment, and methods of evaluating results, 

we will discuss each pond separately.

HENRY POND

The first treatment with 0.4 p.p.b. of antimycin killed about 10 pounds per acre of 

bluegills and redear sunfish, 99.5 percent of 

which were less than 4 inches long (table 3).

Although 50 percent more antimycin was 

used in the second treatment, results were 

virtually nil because of rain which caused the 

pond to discharge through the overflow pipe 

which had been lowered to dewater the pond. 

In addition to diluting the toxicant considerably, the runoff water caused turbidity that 

hampered recovery of the few fish which 

were killed.

The final application of 0.8 p.p.b. of antimycin was made under better conditions, and 

it killed all of the sunfishes except for one 

redear sunfish. About three-fourths of the 

small largemouth bass and one-third of the 

larger bass also died.

TODD POND

The 0.4-p.p.b. application killed no fish 

other than 30.1 percent of the small bluegills 

(table 3). Throughout the 2-week-long recovery period many of these fish were observed in distress. Their moribund condition
Investigations in Fish Control 28; Bureau of Sport Fisheries and Wildlife

TABLE 3. Numbers and weights in pounds per acre and percentages (in parentheses) of various size groups of fishes recovered in

six ponds following treatment with antimycin and at draining1

Pond

Todd .......

Hill.......

Slaughter. .

Biggers. ...

Reynolds, . .

Date

12/05/66

1/13/67

3/08/67

3/20/67

12/08/66

1/09/67

3/07/67

3/20/67

1/31/67

3/07/67

9/18/67

3/13/67

9/07/67

9/1D/67

3/27/67

Average 

temp.

( F *)

59°

54°

69°

48°

47°

62°

52°

65°

65°

75°

69°

Treatment

(0.4 p.p.b.)

Antimycin

(0.6 p.p.b.)

Antimycin

(0.8 p.p.b.)

Drained

(0.4 p.p.b.)

Antimycin

(0.6 p.p.b.)

Antimycin

(0.8 p.p.b.)

Drained

(0.8 p.p.b.)

Antimycin

(1.0 p.p.b.)

Drained

Antimycin

(0.6 p.p.b.)

Drained

Antimycin

(0.4 p.p.b.)

Antimycin

(0.6 p.p.b.)

Combined sunfish species

Lengths 

1.0-3.9 in.

Number

(8.7)

9.0

(0.1)

6,885.0

(91.2)

0

(0.0)

1,380.0

(30.1)

801.4

(17.5)

2,388.4

(52.1)

14.5

(0.3)

(95.9)

11.6

(0.4)

108.9

(3.7)

4,333.0

(88.9)

542.4

(11.1)

2,627.03

6,326.5

Weight

5.1

0.1

61.2

_

8

1

5.4

15.7

25.5

TR.

58.8

50.0

63.3

Lengths 

4.0 or more in.

Number

3.0

(i.o)

0

(0.0)

303.0

(98.7)

1.0

(0.3)

0

(0.0)

1.4

(2.5)

55.1

(97.5)

0

(0.0)

289.3

(97.0)

0

(0.0)

8.9

(3.0)

303.1

(92.6)

24.1

(7.4)

* 263.7

11.8

Weight

0.2

_

19.9

TR. 2

1.5

_

12.3

_

21.8

19.0

1.2

Largemouth bass

Lengths 

1.0-5.9 in.

Number

0

(0.0)

0

(0.0)

5.0

(71.4)

2.0

(28.6)

0

(0.0)

2.9

(5.4)

46.4

(86.6)

4.3

(8.0)

13.3

(78.7)

2.7

(16.0)

0.9

(5.3)

20.1

(34.4)

38.4

(65.6)

264.5

27.4

Weight

_

0.6

TR.

0.2

0.4

0.1

0.4

2.7

0.1

Lengths 

6.0 or more in.

Number

0

(0.0)

0

(o.o)

6.0

(31.6)

13.0

(68.4)

0

(0.0)

0

(0.0)

7.2

(13.1)

47.8

(86.9)

1.3

(12.2)

7.1

(67.0)

2.2

(20.8)

3.1

(31.6)

6.7

(68.4)

1.2

2.5

Weight

_

5.5

_.

8.7

0.3

4.8

4.0

0.2

2.2

Collection 

period

(days)

7

11

7

14

22

7

13

6

9

4

5

1 Reynolds and Diggers ponds were not drained following treatment.

2 TR. = trace, or less than 0.1 pounds per acre.

3 This group included fish up to 4.9 inches in length.

* This group included only fish 5.0 inches or more in length.

was evidenced by blotchy discoloration and 

by shreds of mucus which hung from their 

bodies giving some of them a very ragged appearance. Large bass were observed feeding 

on moribund bluegills on several occasions.

The 0.6-p.p.b. treatment killed an additional 

17.5 percent of the small bluegills, 2.5 percent of the sparse population of larger bluegills, and 5.4 percent of the bass less than 6 

inches long. Behavior and appearance of the 

larger bass were normal, but some of the 

smaller bass which did not die became much

darker in color and their eyes became somewhat grayish and opaque in appearance.

The 0.8-p.p.b. treatment eliminated nearly 

all remaining bluegills, and left only 8.0 percent of the small bass. About 87 percent of 

the adult bass survived, and more than a 

third of these exhibited the same darkening of 

body color and change in eye color previously 

shown by the smaller bass.

When the pond was drained, several adults 

were sent to the National Fish Hatchery in
Burress and Luhning: Antimycin for Thinning Sunfish Populations 7

Marion, Alabama, for breeding tests. None of 

the scores of channel catfish in the pond 

were harmed by the treatments.

SLAUGHTER POND

We recovered 85 pounds of fish per acre 

following a 0.6-p.p.b. application of antimycin 

(table 3). Approximately 90 percent of the 

bluegills of all sizes were killed, as were 

about a third of all sizes of bass.

We recovered 71.4 pounds of fish per acre 

when the pond was drained. Survival of adult 

redear sunfish was greater than that of adult 

bluegills, as was true in all ponds in which 

both species occurred. Reproductive success 

of largemouth bass and sunfishes had been 

good.

HILL POND

The first treatment on January 31 with 0.8 

p.p.b. of antimycin killed about 96 percent of 

the sunfishes of all sizes, nearly 79 percent 

of the bass less than 6 inches in length, and 

12 percent of the larger bass. Since the water 

was cold and deep, the recovery of fish undoubtedly was not as complete as it was following the other tests.

The second treatment amounted to 1.0 

p.p.b., and was made on March 7. It killed a 

few more sunfish, and an additional 16 percent 

of the small bass and 67 percent of the larger 

bass.

The few surviving fish reproduced successfully during the summer, and at draining we 

found a total population amounting to 26.7 

pounds per acre. Large bass finger lings comprised the largest single group by weight in 

the population, amounting to 11.5 pounds per 

acre, while fingerling sunfishes amounted to 

8.0 pounds per acre.

REYNOLDS POND

We recovered 64.5 pounds of sunfishes and 

2.3 pounds of largemouth bass per acre following a single application of 0.6 p.p.b. on 

March 27 (table 3). A few mosquitofish were 

killed, but none of the brown bullheads were 

affected by the treatment.

Reproductive success of bluegills and redear sunfishes was very limited in that only 

four sunfish fry were taken in six short hauls 

with a small-mesh seine on August 29. On 

September 12, four 100-foot hauls made after 

dark with a 75-foot, 1/2-inch-mesh seine took 

131 fingerling bass, 6 bass 5 to 7 inches long, 

28 redear sunfish about 5 inches long, 2 bluegills 6 inches long, and 11 brown bullheads 4 

to 8 inches long, but no sunfish less than 5 

inches long or adult bass were taken.

DIGGERS POND

Following a single application of 0.4 p.p.b. 

of antimycin to this 2.48-acre pond on September 11, we recovered the following weights 

of fish per acre: 2.9 pounds of largemouth 

bass less than 7 inches long; 69 pounds of 

sunfishes including bluegills, redear sunfish, 

redbreast sunfish, and orangespotted sunfish; 

9.0 pounds per acre of fingerling crappie; and 

50.5 pounds of golden shiners from 4 to 9 

inches in length. The treatment had no effect 

on channel catfish or brown bullheads. The 

surface temperature was 75° F. at time of 

treatment and conditions for recovery of fish 

were good, hence the effectiveness of this 

treatment was considerably greater than that 

measured in similar trials conducted in winter. Further tests are to be conducted in this 

pond before it is drained, hence we have no 

way at present to determine what percentages 

of the various groups of fishes were removed 

by the treatment.

DISCUSSION

The results of our exploratory attempts to 

evaluate the use of antimycin in selective 

thinning of sunfishes in small impoundments 

were quite encouraging. Trials made in six 

pounds under a wide variety of weather conditions and temperatures demonstrated that 

low concentrations of antimycin are quite 

selective against populations of panfishes as 

compared to those of largemouth bass, especially at lower temperatures. Treatments 

with a concentration of 0.4 p.p.b. of antimycin 

in December killed upjto 8.4 pounds per acre 

of bluegills less than 4 inches long without 

killing larger bluegills or bass of any size.
8 Investigations in Fish Control 28: Bureau of Sport Fisheries and Wildlife

The same concentration applied in September 

killed 2.9 pounds of small bass and 69 pounds 

of sunfishes of all sizes per acre. Remedial 

stocking with fingerling bass can be done 

easily if it is deemed necessary.

The 0.6-p.p.b. treatments made in small 

ponds less than 8 feet deep in cold weather 

removed up to 13.8 pounds per acre of the 

bluegills less than 4 inches long while killing 

only 0.01 pounds of the small bass. Similar 

treatments in warmer weather killed 80.6 

pounds per acre of bluegills and only 4.4 

pounds of bass in Slaughter Pond, and 64.5 

pounds per acre of sunfishes and 2.3 pounds 

of bass in Reynolds Pond.

The 0.8-p.p.b. treatment proved to be excessively high for use in soft-water ponds in 

which pH values at time of treatment ranged 

from 6.75 to 6.98. Sunfish populations were 

virtually eliminated in three ponds by this 

concentration, bass less than 6 inches long 

were reduced by 78.7 to 94.7 percent, and 

larger bass were reduced by 12.2 to 31.6 percent.

The 1.0-p.p.b. treatment at a temperature 

of 65° F. was entirely too severe, leaving 

only 6.7 percent of the sunfish and 26.1 percent of the bass population.

The costs per acre-foot for treatments reported above when based on the list price of 

$48.00 for an 8.25-pound can of Fintrol-5 

were as follows: 0.4 p.p.b., $0.64; 0.6 p.p.b., 

$0.97; 0.8 p.p.b., $1.28; and 1.0 p.p.b., $1.60. 

If treatments of soft-water ponds such as ours 

were made in warm weather, there is a distinct possibility that concentrations even 

lower than 0.4 p.p.b. would be adequate. A 

treatment in summer might be especially appropriate in ponds in which neither bass nor 

sunfish reproduction was adequate, and in 

which selective removal of a sizeable percentage of the sunfishes could be followed 

shortly by supplementary stocking of bass 

finger lings.

Trials in which fish were held in live boxes 

in water below the 5-foot level showed that 

mortality usually occurred more slowly and

sometimes was reduced in the deeper water. 

Thus, the concentration of antimycin should 

be calculated on the basis of pond volume 

above the thermocline rather than on total 

pond volume if lower levels were stratified or 

uncirculated by wind or other factors. Otherwise, the concentration might be higher than 

intended, with a correspondingly greater reduction in the fish population. In the case of 

Diggers Pond, for example, the 578 grams of 

toxicant used to produce a 0.4-p.p.b. concentration of antimycin in the entire pond volume 

would have produced a 0.5-p.p.b. concentration if all of the antimycin had been confined 

to the area above the 5-foot depth at which the 

thermocline was located. Had this occurred, 

the concentration would have been 25 percent 

greater than intended, which would have made 

a considerable difference in results. In any 

case, conservative calculation of the volume 

of water to be treated is preferable to reduce 

the possibility of overdosage.

Weather and water conditions were regarded as major causes for poor results following the 0.4- and 0.6-p.p.b. treatments of 

Henry Pond. However, there also is a definite 

possibility that little benefit was derived from 

the antimycin which was not released before 

the sand-formulated material sank into the 

soft, muddy bottom of the partially dewatered 

pond. Thus, lowering a pond prior to treatment with a given amount of Fintrol-5 will not 

necessarily yield better results than would 

have been achieved if the pond had not been 

lowered. Furthermore, complete eradication 

of fish often is easier to achieve in a full pond 

than in one which has been drained. This is 

true because pond bottoms usually contain 

irregularities which may hold enough water to 

keep fingerling fish alive for several days, 

and it is difficult to be certain that fish in all 

pockets of water have been eliminated.

We found conclusive evidence that largemouth bass, bluegills and redear sunfish were 

able to reproduce successfully after one or 

more exposures to antimycin. Adult bass 

which were exposed to successive treatments 

of 0.4, 0.6, and 0.8 p.p.b. of antimycin during 

the period December 8, 1966, to March 7, 

1967, were able to reproduce normally in
Burress and Luhning: Antimycin for Thinning Sunfish Populations

broodponds at the National Fish Hatchery, 

Marion, Alabama in April 1967 1 . Bass, bluegill and redear sunfish which survived exposure to concentrations of 0.8 and 1.0 p.p.b. 

on January 1 and March 7, 1967, spawned 

successfully in Hill Pond, as did the same 

species in Slaughter and Reynolds ponds 

which were treated with a concentration of 

0.6 p.p.b. of antimycin. One interesting observation was made in relation to the effect 

of antimycin on adult fish. During the period 

from March 7 to March 28, 30 of 39 adult 

bass found dead in five ponds were gravid 

females. Thus, females apparently are more 

vulnerable than males just prior to the spawning season.

We found no difference in results obtained 

by the three methods used to apply Fintrol-5 

during these trials. The simplest and easiest 

method was to dribble the material out a 

small hole in a container held over the bow of 

the boat. Dispersion of toxicant was adequate 

in open water of the larger ponds even when 

successive passes of the boat were about 30 

feet apart. However, in shallow, weedy areas 

where circulation was restricted we applied 

the material at intervals of not more than 10 

feet in an effort to avoid gaps in coverage.

The Fintrol-5 formulation of antimycin 

gives very good selective control of sunfishes 

in soft-water ponds at comparatively low cost. 

The material is easy to apply, and applications can be made over a very wide range of 

water temperatures and with a minimum of 

regard for weather conditions. Much remains 

to be done in working out techniques suited to 

waters of different qualities and in devising 

variations in methods for application. Possibly liquid formulations of antimycin could be 

introduced well below the surface to reduce 

populations of crappie or other species that 

inhabit deeper water; manipulation of water 

flows might be used to attract or to concentrate certain species which then could be 

treated; concentrations of spawning fishes or 

nest areas might be treated; shoreline applications of antimycin might be used to cut 

treatment costs even further.

1 Personal communication from Jack R. Snow, 

Station Director, Marion NFH, Marion, Alabama, 1967.

SUMMARY

1. Selective removal of sunfishes was accomplished in six soft-water ponds in west 

central Georgia by applications of 0.4, 0.6, 

0.8, and 1.0 parts per billion (p.p.b.) of 

antimycin in the Fintrol-5 formulation. 

The treatments were made during winter, 

spring, and late summer at water temperatures ranging from 46° to 75° F. and 

under a variety of weather conditions. 

\

2. Smaller fish of each species are more 

susceptible than adults; redear sunfish 

are more resistant than bluegills; and 

even fingerling bass are more resistant 

than adult sunfishes.

3. Response to treatment occurred more 

slowly in colder water, and all species, 

especially largemouth bass, appeared to 

be more resistant to antimycin at low 

temperatures.

4. The 0.8- and 1.0-p.p.b. concentrations 

were too high even in winter, and there 

are indications that concentrations less 

than 0.4 p.p.b. might be adequate when 

water temperatures are 75° F. or more 

and the pH is about neutral.

5. The toxicant is easy to apply, and costs 

only $0.64 per acre-foot at a concentration of 0.4 p.p.b.

6. Largemouth bass, bluegill and redear sunfish which survived multiple exposures to 

antimycin were able to reproduce normally.

7. Use of antimycin for selective thinning of 

sunfishes will enable fishery managers to 

utilize this valuable technique for a longer 

time each year than previously was possible.

REFERENCES

Bennett, George W.

1962. Management of artificial lakes and ponds. 

Reinhold Publishing Corporation, London, 

England. 283 p.
10 Investigations in Fish Control 28: Bureau of Sport Fisheries and Wildlife

Hooper, Archie D., and Johnie H. Crance.

1960. Use of rotenone in restoring balance to 

overcrowded fish populations in Alabama lakes. 

Transactions of the American Fisheries Society, 

vol. 89, No. 4, p. 351-357.

Lennon, Robert E., Bernard L. Berger, and Philip A. 

Gilder hus.

1967. A powered spreader for antimycin. 

Progressive Fish-Culturist, vol. 29, No 2, 

p. 110-113.

Swingle, H. S., E. E. Prather, and J. M. Lawrence.

1953. Partial poisoning of overcrowded fish populations. Agricultural Experiment Station of Alabama 

Polytechnic Institute, Circular No. 113. 15 p.

Thomaston, W. W.

1962. The results of population alteration and factors affecting balance in farm ponds in Georgia. 

Proceedings of the Sixteenth Annual Conference 

of the Southeastern Association of Game and Fish 

Commissioners, Charleston, South Carolina, 

October 14-17, p. 361-370.

U. S. GOVERNMENT PRINTING OFFICE : 1969 O - 338-447