UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

DEC 1 3 2006 

OFFICE OF 

PREVENTION, PESTICIDES AND 

TOXIC SUBSTANCES 

MEMORANDUM 

SUBJECT: Alternatives Analysis for Antimycin A and Rotenone in Lakes and 

Streams (DP# 3 10753 and 307400) 

FROM: Monisha Kaul, Biologist C; ! L'L?~~-' /i f/.tui z 

Nicole Zinn, Biologist 

Biological Analysis Branch 

John Faulkner, Economist 

Economic Analysis Branch &$- 

Biological and Economic Analysis Division (7503P) 

THRU: Arnet Jones, Chief 

Biological Analysis Branch 

Id r+upi-Lt\ Richard Keigwin, Acting Chief ,Y-rx-' xL-"i"-i , :p 

Economic Analysis Branch 

Biological and Economic Analysis Division (7503P) 

TO: Lance Wormell, Chemical Review Manager 

Katie Hall, Chemical Review Manager 

Special Review and Reregistration Division (7508P) 

Peer Review Panel: November 29,2006 

Summary 

Rotenone and antimycin A are the only two broad spectrum piscicides registered in the 

United States. Rotenone and antimycin A appear to have niche uses, although both can 

be applied in a variety of situations. In general, antimycin A is used to repopulate native, 

threatened, or endangered trout species in streams by eliminating nonnative fish species, 

particularly in high-altitude alpine lakes and streams because it is effective in cold alpine 

waters and where pH is low. In addition, this piscicide may be used at low 

concentrations, which makes it easy to transport to isolated or hard to reach mountainous 
streams. Rotenone is most often used in standing water, such as large lakes and 

reservoirs. It is often applied to maintain sport fisheries, sample fish populations, and in 

rearing ponds. The costs of rotenone and antimycin A are similar. For sampling fish 

populations alternatives to rotenone, such as electrofishing, appear to be available. 

However, for water bodies requiring selective or complete kill of certain fish species, 

rotenone and antimycin A are effective. Dewatering is effective for complete kill in a 

water body. In select cases, gill netting, which generally only reduces fish populations, 

has been used to remove all fish from certain mountain lakes in California. 

Although some uses of rotenone and antimycin A coincide, they are not complete 

replacement for each other because each has niche uses. Because there are no other 

broad spectrum piscicides available, the only possible alternatives are non-chemical fish 

control methods and none are applicable for all uses of rotenone or antimycin A. In 

situations where dewatering or electrofishing are potential replacements, it is not clear if 

these are more cost effective methods. 

Background 

BEAD has conducted an alternatives analysis for antimycin A and rotenone as part of the 

risk mitigation and reregistration process. Occupational and ecological risks of concern 

were identified for rotenone primarily associated with inhalation of the dust formulation, 

contamination of the liquid formulations with trichloroethylene and the strong reliance of 

the formulated end product on aromatic hydrocarbons. Risks of concern for antimycin A 

were not identified because HED did not conduct a quantitative risk assessment due to 

the absence of data; however, the concerns for formulated endproduct were not as great 

since antimycin is less reliant on co-solvents. Antimycin A and rotenone are the only two 

EPA registered piscicides. The product Fintrolo, manufactured by Aquabiotics 

Corporation, contains the active ingredient antimycin A. It is an antibiotic produced fkom 

Streptomyces bacteria, which kills fish by blocking cellular respiration. Rotenone is 

derived from certain tropical plants in the Leguminosae family and also inhibits cellular 

respiration (Finlayson, et al., 2000; Ware, 2000). BEAD has evaluated the two 

registered piscicides as alternatives to each other and to other non-chemical fish control 

methods. In the case of rotenone, which may also be used to sample fish populations, 

BEAD reviewed several other sampling techniques available. 

Antimycin A Use and Usage 

Antimycin A is used to selectively or completely kill fish species from freshwater 

streams and shallow lakes and ponds. The FintrolB label recommends that it be applied 

to lakes and ponds by boat bailer or spray. Boat bailer and drip tube applications are 

useful for depths greater that 1 foot. Backpack sprayers may be used for isolated areas. 

Drip stations may be used for stream applications. Aircraft applications are not 

recommended according to the label. 

Antimycin A either completely or selectively kills fish based on the concentration used. 

Fish species and sizes also vary in their sensitivity. For example, the label indicates trout 
are more sensitive to antimycin than catfish. The label recommended concentrations 

range &om 0.5 to 25 parts per billion (ppb) and varies based on the pH and temperature 

of the water. Therefore, the appropriate concentration must be determined based on 

several factors. Complete kills require concentrations greater than five ppb. Bioassays 

are required to determine the correct concentration, particularly for selective kills. 

EPA proprietary data indicate that antimycin A accounts for less than five percent of the 

area treated with piscicides or 4,000 acre-treatments in 1998 and the total use was less 

than 200 pounds. In addition, the primary use is for endangered fish repopulation efforts. 

More recent usage information is not available, although available publications indicate 

that limited quantities of antimycin A are available (Finlayson et al, 2000; Marking, 

1992). 

A common use for Antimycin A is to repopulate native, threatened, or endangered trout 

species to streams by eliminating nonnative fish species. Antimycin A is particularly 

usell in high alpine lakes and streams because it is effective in cold alpine waters and 

where pH is low (Schenk, 2002; Stevens, 2001). In addition, this piscicide may be used 

at low concentrations, which makes it portable to isolated or hard to reach mountainous 

streams. Antimycin A is effective for removal of unwanted salmonids, which is 

important for the reintroduction of native fish. Another advantage of antimycin A use in 

streams is that it may be neutralized it with potassium permanganate in downstream 

locations. A disadvantage is that multiple applications may be needed because antimycin 

A breaks down quickly. In addition, potassium permanganate may be harmful to some 

fish. 

Commercial catfish production is the primary form of aquaculture in the U.S (Mississippi 

State University Extension Service, 2006) Antimycin A is can be used to remove 

unwanted scaled fish from catfish production ponds (Wynne, 2002). Catfish are less 

sensitive to Antimycin A and therefore may be able to tolerate this piscicide, while other 

unwanted fish are removed. Antimycin A may also be used to remove unwanted fish 

without harming catfish in ponds used for recreational fishing (Cichra, 2003). 

Antimycin A has also been used for restoration of alkaline, hardwater streams in 

southwestern U.S. (Weedman et al., 2005). A stream restoration project in Arizona 

involving the removal of two nonnative fish, green sunfish and small mouth bass, used 

two formulations of antimycin A, a liquid concentrate and coated sand grains. Multiple 

applications at concentrations of 50 to 100 ppb were used to successfully remove the 

target fish. 

Rotenone Use and Usage 

A U.S. and Canadian survey of rotenone use was done to obtain information on rotenone 

use and usage, as well as determine other issues with its use, as part of the development 

process for the rotenone stewardship plan for the Rotenone Stewardship Program 

(McClay, 2000). Responses were received from agencies in 48 states. Nearly all of the 

rotenone (97.5%) applied between 1 988 and 1997 was applied to standing water. 
Rotenone was applied for a number of different reasons. In terms of number of 

treatments, rotenone was most commonly used to maintain sport fisheries, sample fish 

populations, and in rearing ponds. In terms of amount of standing water treated, rotenone 

was largely used to maintain fisheries and to eradicate exotic species. In terms of length 

of flowing water treated, rotenone was used largely to maintain fisheries, for disease 

eradication, and restoration of threatened and endangered species. (McClay, 2000) These 

same uses of piscicides are described in the Rotenone Use in Fisheries Management: 

Administrative and Technical Guidelines Manual (Finlayson et al, 2000). 

Pounds of rotenone used were calculated from the survey results. Between 1988 and 

1997, approximately 209,000 lbs active ingredient (ai) were applied, including 

approximately 46,000 lb ai for one particularly large project (McClay, 2000). According 

to sales data, approximately 23,000 lb ai of rotenone were applied in 1998. The main use 

site was catfish ponds in the south (EPA proprietary data, 1998). 

The application rates found in various publications are also those found on rotenone 

labels. A Mississippi publication on farm pond use of rotenone lists application rates 

between 0.025 and 0.150 ppm ai (Brunson, 2004). A South Carolina publication for 

rotenone suggests similar rates, with a range of 0.025 to 0.2 ppm, and for selective 

control suggests rates of 0.005 to 0.007 ppm ai rotenone (Whetstone, Smith, and Watson, 

2001) The wide range of rates reflects the need to use higher rates to control certain fish 

species (Rotenone labels; Brunson, 2004; Whetstone, Smith, and Watson, 2001). The 

rotenone labels also list a preimpoundment treatment above dams which include higher 

rotenone rates of 0.15 to 0.25 ppm ai. The exception to these labels is prenfishm Grass 

Carp Management Bait (EPA Reg. # 655-795), which is designed specifically to attract 

and kill grass carp. 

According to EPA source data, piscicide usage varies from year to year depending on the 

projects being done to remove fish. In 1998, less than 1 percent of surface water acreage 

in the U.S. was treated with a piscicide, with nearly half of the treatments occurring in the 

South. Most applications occur in the fall. The method of application varies with the 

body of water treated. Lakes and reservoirs are treated by boat, streams with a drip 

applicator, and small water bodies by hand fi-om the edge of the water body. Most 

piscicides sold are of the liquid formulation. For rotenone, the liquid formulation is 

primarily used by private applicators whereas the powder formulation is used by 

government agencies (EPA proprietary data, 1998). 

Fish species vary in their sensitivity to rotenone. Some species, such as catfish, are less 

susceptible to rotenone than other fish (Brunson, 2004). In addition, the rotenone labels 

state that "factors such as pH, temperature, depth and turbidity will change 

effectiveness." 

Rotenone can be used to sample fish populations and communities. Although rotenone 

has advantages over other sampling methods, such as the ability to use to sample large 

streams, one disadvantage is that most fish will not survive (Finlayson et al, 2000). 
Like antimycin A, rotenone can be neutralized with potassium permanganate (Finlayson 

et al, 2000). 

Alternatives Analysis 

There are several methods that can be used to remove unwanted fish: electrofishing, 

angling, netting, or use of piscicides. 

Piscicides 

The only available registered broad spectrum piscicides are antimycin A and rotenone. 

Both rotenone and antimycin a may be used in fish ponds, although for different 

purposes. Antimycin A is used to selectively control certain fish species in ponds 

whereas rotenone is generally used for reclamation, which involves removing all fish and 

then restocking with the desired fish species. In some cases, selective treatments with 

rotenone may be possible with certain application techniques or if the target fish species 

is particularly sensitive to rotenone. (Wynne, 2002) 

Rotenone is effective in larger water bodies where antimycin A is not. While rotenone is 

more effective at higher pH levels than antimycin A, it may degrade slower and may be 

more harmful to non-target macroinvertebrates. Although antimycin A generally takes 

days to degrade, rather than days to weeks in the case of rotenone, at high pH values it 

may degrade within hours (Lennon, et al., 1971). Another disadvantage of rotenone is 

that it may repel fish because it is detected by fish. Rotenone requires higher quantities 

as compared to antimycin A, which limits its use in isolated areas because it is less 

portable. Both rotenone and antimycin A may cause temporary loss of potable water. 

Antimycin A may not be available or registered in all states (Finlayson et al, 2000). 

Lampricides 

Two lampricides are registered in the U.S. These chemicals are TFM (3-trifluoromethyl4-nitrophenol) and niclosamide. Both of these chemicals are registered for the control of 

sea lampreys, and niclosamide is also registered for the control of snails. In general the 

lampricides, particularly TFM, do not kill fish, although some fish species may be 

susceptible (Great Lakes Fishery Commission, 2004). These lampricides are not 

expected to be alternatives to rotenone and antimycin A. 

Dewatering 

Dewatering an area and application of piscicides are described as the only ways to 

eliminate all fish fi-om an area (McClay, 2000; Finlayson et al, 2000). However, 

dewatering may be detrimental to non-target organisms or have other environmental 

consequences (Finlayson et al, 2000). 

Gill Netting 

There are several methods of fish netting. Gill netting is a common practice that may 

reduce but generally does not completely eliminate fish populations. Gill netting is not 

considered a complete alternative to rotenone and antimycin A. 
As mentioned above, dewatering an area and application of piscicides are often described 

as the only ways to eliminate all fish from an area (McClay, 2000; Finlayson et al, 2000). 

However, in at least some mountain lakes, gill netting appears to be feasible to eliminate 

fish. Gill netting causes fish to become trapped in a net, thus eliminating at least a part of 

the population from an ecosystem. Nets are available in different sizes, which may allow 

for some selectivity of species and within species. In one study it was possible to 

eliminate trout from a mountain lake in California over a two to three year period. 

However, gill netting was described as not being feasible for all mountain lakes. Gill 

netting was successful at removing trout in the study because the lake is relatively small, 

not very deep, there was little stream flow into and out of the lake, and there was no fish 

stocking (Knapp and Matthews, 1998). In addition, gill netting may not be feasible in 

areas where non-target fish or other non-target organisms are present. A survey of lakes 

near the study area found that in 15 to 20 percent of the lakes, gill netting may be a 

feasible alternative to eliminate trout. It was also noted that in lakes where gill netting is 

not feasible, removal of trout would need to be done with rotenone (Knapp and 

Matthews, 1998). A subsequent presentation and discussion by Knapp indicated that 

intensive gill netting has been successfbl in several mountain lakes (Knapp, 2005). 

Netting may also be difficult to implement in mountainous stream settings and would 

need to be repeated only to keep populations low. Gill netting can be effective in lakes 

up to 2 hectares in size that are clear of debris (US Department of the Interior, 2003). 

However, gill nets may harm non-target species such as birds. Additionally, netting is 

labor and time intensive (Pfeifer et al., 2001). 

Electrojishing 

Electrofishing involves stunning and then capturing fish by applying electricity to water 

(Allen-Gil, 2000). This is a commonly used technique for fish surveys such as 

population counts. In terms of complete fish removal, it appears that electrofishing has 

had mixed results. Buktenica et al. (2001) successfully reduced the population of 

unwanted brook trout using diver-directed electrofishing over several years. Moore et al. 

(2001) indicate that electrofishing is useful for reduction of targeted fish such as rainbow 

trout. Other sources indicate that electrofishing may not be useful for all fish types and 

that fish may sense the current and hide from netters. Injury to fish is possible with 

electrofishing, with one of the worst effects being broken backs. However, it is noted 

that in general there is no substantial impact on the population. Several factors may result 

in variability in electrofishing effectiveness. These factors include fish species, size, and 

other fish characteristics, water temperature, time of year, and other factors (Temple and 

Pearsons, 2005). For example, large fish are more susceptible to electrofishing than 

smaller fish (Allen-Gil, 2000). Electrofishing may be ineffective in complex stream 

habitats. It appears to be common practice to follow electrofishing with a piscicide 

application to ensure complete eradication. 

Other 

Angling is described as ineffective way to control fish populations for several reasons, 

one of which is that some species may not be susceptible to angling (Finlayson et al, 
2000). Increased angling pressure appears to be somewhat successful for reducing 

unwanted fish populations from streams. This method is not effective for elimination of 

all fish as smaller fish are generally not caught (Moore et al., 2005). Anglers are also less 

likely to reach isolated mountain streams. Increased angling may provide only temporary 

population reduction. 

An article from Taiwan comparing rotenone to clove oil indicated that clove oil could be 

used to sample and collect fish, while keeping them alive, in subtropical intertidal areas 

(Wen, et al, 2005). However, it does not appear that this use of clove oil is registered in 

the U.S. 

Economics 

Piscicides 

The costs of rotenone and antimycin A are comparable. The cost of rotenone per acrefoot in 1998 varied from about $2 - 13 at low application rates and $45 - 137 at high 

application rates, while the cost of antimycin A was about $47 per acre-foot (EPA 

proprietary data, 1998). The cost of applying these piscicides is generally more costly 

than the piscicides themselves depending on the situation. Antimycin A has the 

advantage of being active in smaller amounts and thus may be less costly to apply in 

remote areas. 

Gill Netting 

A study compared the costs of fish eradication using of rotenone to that of gill netting in 

a small mountain lake (Knapp and Matthews, 1998). The total costs including 

application costs were comparable for both methods. However, most of the cost of 

rotenone was applying it by helicopter. Where economies of scale of applying rotenone 

by helicopter may be applicable in larger lakes, rotenone may be less costly than gill 

netting. Also, in less remote locations other application methods of applying rotenone 

may be less costly than helicopter application; and therefore, less costly than gill netting. 

Other application methods 

We have not found costs for the alternatives that could be compared to the cost of using 

piscicides. For example, some costs are available using electrofishing for sampling fish, 

but it is not clear what these costs would be for eliminating all fish of a species. The 

costs of dewatering would vary widely from draining an aqua-culture pond to dewatering 

a large lake where significant capital costs could be incurred with excavation equipment 

and structures required to hold and to control the water. 

Economic conclusion 

Because the costs, feasibility, and efficacy of the alternatives vary widely depending on 

the situation, we cannot conclude which method is most cost effective. It depends on the 

situation. 
References 

Allen-Gil, S.M., ed., 2000, New Perspectives in Electrofishing, U.S. 

Environmental Protection Agency, Office of Research and Development, Report # 

EPA/600/R-991108 

Brunson, M.W., Last Modified 2004, Using Rotenone to Renovate Fish Populations in 

Farm Ponds, Mississippi State university Extension Service, Web address: 

htt~://msucares.com/pubs/vublicationslv 1 954.htm 

Buktenica, M.W., B.D. Mahoney, S.F. Girdner, and G.L. Larson, 2001. Response of 

resident bull trout population to nine years of brook trout removal, in Sun Creek, Crater 

Lake National Park, Oregon. Practical approaches for conserving native inland fishes of 

the west abstracts. Missoula, MT, 6-8 June 2001. Web Address: 

http://www .fisheries.org~AFSmontana~Misc/Symposium%2OAbstracts/Abstracts.pdf. 

Cichra, C.E, 2003. Managing Florida ponds for fishing. University of Florida IFAS. 

Web Address: httv://edis.ifas.ufl.edu/FAOOl . 

Finlayson, B. J., R. A. Schnick, R. L. Cailteux, L. DeMong, W. D. Horton, W. McClay, 

C. W. Thompson, and G. J. Tichacek. 2000. Rotenone use in fisheries management: 

administrative and technical guidelines manual. American Fisheries Society, Bethesda, 

Maryland. Accessible at htt~://www.fisheries.ordrotenone/Rotenone Manual.vdf 

Great Lakes Fishery Commission, 2004, Larnpricides and Facts about Stream 

Treatments, Fact Sheet 4a, Web address: http://www.glfc.orglpubs/FACT-4a.pdf 

Knapp, R.A. and K.R. Matthews, 1998, Eradication of Nonnative Fish by Gill Netting 

from a Small Mountain Lake in California, Restoration Ecology, Vol. 6 No. 2, pp. 207- 

213. 

Knapp, R., 2005, "Turning Back the Clock: Restoring Lake Ecosystems by Eradicating 

Introduced Fish," Transcript of Presentation and Discussion at New Currents in 

Conserving Freshwater Systems, Spring Symposium 2005, Center for Biodiversity and 

Conservation, American Museum of Natural History, Web address: 

ht~://cbc.amnh.ordsynvosia~fieshwater/index.html 

Lemon, E. R., J.B. Hunn, and R.A. Schnick, 197 1. Reclamation of ponds, lakes, and 

streams with fish toxicants: A review. FA0 Fish. Tech. Pap. (100):99. Web Address: 

http://~~~.fao.orn/docre~/003/B0465E/B0465E05 .htm 

Marking, L.L., 1992. Evaluation of toxicants for the control of carp and other nuisance 

fishes. Fisheries, 17(5):6-13. 

McClay, W., 2000, Rotenone Use in North America (1988-1997), Fisheries, Vol. 25, No. 

5. 
Mississippi State Universtity Extension Service, 2006. Aquaculture: Catfish. Web 

Address: http://msucares.com~aquaculture/catfi~hlinde~.ht~nl) 

Moore, S., M. Kulp, and J. Hamrnonds. Brook trout restoration, Great Smoky Mountains 

National Park: Lessons for today. Practical approaches for conserving native inland fishes 

of the west abstracts. Missoula, MT, 6-8 June 2001. Web Address: 

http://www.fisheries.org/AFSmontana~Misc/Symposium%20Abstracts/Abstracts.pdf. 

Pfeifer, B. M. Swayne, and B. Curtis, 2001. Washington Department of Fish and 

Wildlife's High lakes fishery management program. Web Address: 

http://wdfw.wa.gov/fish/hinh lakeshigh lakes final vart2b.pdf. 

Stevens, D.R., 2001. Resotoration of native fish to Rocky Mountain National Park. 

Practical approaches for conserving native inland fishes of the west abstracts. Missoula, 

MT, 6-8 June 2001. Web Address: 

http:Nwww.fisheries.org/AFSmontana~Misc/Symposium%2OAbstracts/Abs~acts.pdf. 

Temple, G.M. and T.N. Pearsons, 2005, Backpack and Drift Boat Electrofishing Design 

Considerations and Sampling Protocols, Washington Department of Fish and Wildlife, 

Web address: 

http://~w~.vnamp.org//web/w0rk~o~v~/FPM~meeting~/2005 1205/2005 1202Electrofis 

hing.doc 

US Department of the Interior, 2003. Mountain lakes fishery management environmental 

impact statement public scoping meetings, March 2003. National Park Service, North 

Cascades National Park Service Complex. Web Address: 

htt~://www.nvs.gov/archive/noca/Mtnlakeinl .htm. 

Ware, G.W., 2000, The Pesticide Book, 5th Edition, Fresno, CA: Thompson Publications 

Weedman, D.A, P. Sponholtz, S. Hedwall, 2005. Fossil creek native fish resotoration 

project: Final project report, November, 2005. Arizona Game and Fish Department. 

U.S. Fish and Wildlife Service. Web Address: 

htt~://ww~.az~rfd.rrov/~dfs/w cltech revorts/Fossi1%2OCreek%2ORestoration.vdf 

Wen, K-C, K-T Shao, L-T Ho, and L-S Chen, Accepted 2005, A Comparison between 

.Clove Oil and Rotenone for Collecting Subtropical Intertidal Fishes, J. Fish. Soc. Taiwan, 

32(1):29-39. 

Whetstone, J.M., D.C. Smith, and M. Watson, 2001, Use of Rotenone for Management of 

Fish Populations, Clemson extension, Web address: 

htt~://hgic.clemson.edu/factsheets/HGIC 17 13 .htm 

Wynne, F., 2002, Removal of Undesirable Fishes from Warmwater Ponds, Kentucky 

State University Cooperative Extension Program, Accessed 2006, Web address: 

http:llaquanic.ornlpublicat/state/k~/unwanted.htm