INVESTIGATIONS IN FISH CONTROL

22. Efficacy of Quinaldine as an Anesthetic 

for Seven Species of Fish

23. Toxicity of Quinaldine 

to Selected Fishes

24. Quinaldine as an Anesthetic 

for Brook Trout, Lake Trout, 

and Atlantic Salmon

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. (Bureau Circular 185.) 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. (Bureau 

Circular 186.) 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. (Resource Publication 7.) 1966. 16 p.

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

Robert G. Needham. (Resource Publication 8.) 1966. 16p.

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

Toxaphene, by Donald C. Warnick. (Resource Publication 9.) 1966. 9 p.

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

Ahmed Mahdi. (Resource Publication 10.) 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. (Resource Publication 11.) 1966. 7p.

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

Alaska, by William R. Meehan and William L. Sheridan. (Resource Publication 12.)

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. (Resource Publication 13.) 1966. 12p.

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

(Resource Publication 14.) 1966. lOp.

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

Schoettger and Arnold M. Julin. (Resource Publication 15.) 1966. lip.

(Reports 12 through 17 are in one cover.)

12. Toxicity of MS-222 to Selected Fishes, by Leif L. Marking. (Resource Publication 18.)

1967. lOp.

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

Arnold M. Julin. (Resource Publication 19.) 1967. 15p.

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

Schoettger. (Resource Publication 20.) 1967. lOp.

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

Richard A. Schoettger. (Resource Publication 21.) 1967. lip.

16. Annotated Bibliography on MS-222, by Richard A. Schoettger. (Resource Publication 22.) 

1967. 15p.

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. (Resource Publication 33.) 1967. 14p.

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 
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Schoettger, Ri

1969. Investi

The efficacy o

for seven spec

Sport Fisherie

37-85 millilit

Delete: Bove, 

Meist

Ch

Steen
INVESTIGATIONS IN FISH CONTROL

22. Efficacy of Quinaldine as an Anesthetic 

for Seven Species of Fish

By Richard A. Schoettger and Arnold M. Julin, Fishery Biologists

23- Toxicity of Quinaldine to Selected Fishes 

By Leif L. Marking, Chemist

2k. Quinaldine as an Anesthetic for Brook Trout, 

Lake Trout, and Atlantic Salmon

By David 0. Locke

United States Department of the Interior

Fish and Wildlife Service 

Bureau of Sport Fisheries and Wildlife
CONTENTS

Pages

Efficacy of Quinaldine as an Anesthetic for Seven Species

of Fish, by Richard A. Schoettger and Arnold M. Julin . 1-10

Toxicity of Quinaldine to Selected Fishes, by Leif L.

Marking ........................ 1-10

Quinaldine as an Anesthetic for Brook Trout, Lake Trout,

and Atlantic Salmon, by David 0. Locke ........ 1-5
INVESTIGATIONS IN FISH CONTROL

22. Efficacy of Quinaldine as an Anesthetic 

for Seven Species of Fish

By Richard A. Schoettger and Arnold M. Julin, Fishery Biologists

UNITED STATES DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

Bureau of Sport Fisheries and Wildlife 

Washington, D.C. January 1969
CONTENTS

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

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

Results and discussion ...................... 5

Behavior of anesthetized fish ................. 5

Efficacy ............................ 6

Effects of pH ....................... 6

Effects of water hardness ................. 6

Effects of repeated anesthetization ............. 6

Effects of aging ...................... 8

Repeated use of solutions ................. 8

Toxicity to eggs ........................ 8

Metabolism of quinaldine ................... 8

Summary ............................. 9

References ............................ 9
EFFICACY OF QUINALDINE AS AN ANESTHETIC 

FOR SEVEN SPECIES OF FISH

By Richard A. Schoettger and Arnold M. Julin, Fishery Biologists

Bureau of Sport Fisheries and Wildlife 

Fish Control Laboratory, La Crosse, Wisconsin

ABSTRACT.--Quinaldine was tested as an anesthetic for rainbow 

trout, brown trout, brook trout, lake trout, channel catfish, bluegill, 

and largemouth bass. In general, 15 to 70 ppm of the drug induce 

total loss of equilibrium in fish within two minutes . Efficacy is influenced by acid pH and for some species, by temperature, but not 

by water hardness, age of quinaldine solutions, or repeated exposures 

of fish to quinaldine. Assets include rapid action and prolonged 

maintenance of anesthesia, but anesthetized fish retain a degree of 

reflex responsiveness which may interfere with stripping, delicate 

surgical operations, and blood collection. The drug is harmless to 

fertilized rainbow trout eggs at concentrations and exposure times 

normally encountered in spawning operations .

Quinaldine (2-methylquinoline) is obtained 

from coal tar and is used in the manufacture of 

dyes (Turner, 1950). Its anesthetic effect on 

fish was first reported by Muench (1958), who 

found that concentrations of 2.5 to 20 ppm narcotized goldfish, golden shiners, yellow bullheads, green sunfish, and white crappies within 

0.5 to 4 minutes. The relatively small number 

of published reports on the use of quinaldine as 

a fish anesthetic, in contrast to MS-222 

(Schoettger, 1967), suggests that it is not widely 

used by fishery workers. However, in our survey of chemicals used at national fish hatcheries, 

we found that it is employed in handling a variety 

of species including sockeye salmon, chinook 

salmon, coho salmon, rainbow trout, brown 

trout, brook trout, northern pike, goldfish, 

channel catfish, smallmouth bass, largemouth 

bass, and walleye. Natarajan and Ranganathan 

(1960) used quinaldine in fish transport, and 

Greenough (1963) patented a fish-transport 

medium containing a buffer, an antibiotic, and 

quinaldine. Penfold (1965) found the anesthetic 

useful in the live collection of certain marine 

species.

Recent amendments to the Federal Food, 

Drug, and Cosmetic Act require that chemicals 

used on fish be cleared and labeled for their 

specific uses(Lennon, 1967). The information 

needed to clear quinaldine includes its toxicity 

to fish, its efficacy as an anesthetic, its 

residues in fish tissues, and its safety to other 

animalp . The intent of our research was to 

extend Muench's (1958) investigations on efficacy 

to include species more commonly cultured in 

hatcheries, such as fingerling and adult trout, 

catfish, and centrarchids. Also, we wished to 

study the influence of temperature, water quality, 

and repeated narcosis of fish on the efficacy and 

stability of quinaldine solutions, and the toxicity 

of quinaldine to trout eggs.

Spector (1956) cited an oral LD^Q for rats 

of 1.23 g./kg. and a cutaneous toxicity to 

rabbits of 1.87 g./kg. Both values classify 

quinaldine as slightly toxic to mammals. Bell 

(1964) recommended avoidance of vapor inhalation and prolonged skin and eye contact. 

According to personal communication from 

Dr. Hans L. Falk, Associate Director for
Carcinogenesis, National Cancer Institute, Department of Health, Education and Welfare, 

Bethesda, Maryland, November 10, 1966, there 

is no evidence that quinaldine has carcinogenic 

properties, either on the basis of bioassay, or 

on correlation with structural requirements for 

carcinogenicity. Quinaldine N-oxide, the only 

related chemical they tested for carcinogenicity, 

was inactive.

METHODS AND MATERIALS

Quinaldine used in these investigations was 

95 percent technical material purchased from 

Eastman Kodak Company. Efficacy of the 

chemical was tested with rainbow trout, brown 

trout, brook trout, lake trout, channel catfish, 

and largemouth bass of two to six inches and 

seven to 12 inches (table 1). Bluegills of two to 

six inches were also tested. The trials with 

trout were conducted at 7° , 12° , and 17° C., 

and those with channel catfish and centrarchids 

at 7° , 12° , 17° , 22° , and 27° C.

The methods of preparing test solutions and 

various water qualities, acclimating the test 

fish, and evaluating efficacy were essentially 

the same as those described by Schoettger and 

Julin(1967), with some modifications. The 

major modifications were in the preparation of 

stock solutions and in the criteria for efficacy. 

Stock solutions were prepared by diluting the

compound with acetone and water. Sufficient 

acetone was added to produce clear solutions.

The changes in criteria for efficacy were 

related to the differences in behavioral responses 

of quinaldine-treated and MS-222-treated fish. 

The responses of the former are discussed 

later. Concentrations inducing total loss of 

equilibrium (stage 11) within 2 minutes were 

considered effective. Following application of 

anesthesia, the fish were held in the test 

solutions until they entered medullary collapse, 

or for 6 hours, whichever occurred first. This 

period gave a measure of the tolerated exposure 

time The fish were then placed in flowing well 

water for recovery.

During the investigations, we observed 

that pH influenced the effectiveness of quinaldine. 

Additional trials were carried out to better define this influence and to determine whether it 

was reversible with changes in pH. Smallmouth 

bass were tested in solutions containing 20 and 

30 ppm of quinaldine; channel catfish in 50 and 

60 ppm. The pH of solutions was manipulated 

with IN sodium hydroxide and 0.25M phtharlic 

acid. The test solutions were maintained at 

12° C. in water baths.

The influence of water hardness on the 

efficacy of quinaldine was measured with 2.5- 

inch rainbow trout at 12° C. Solutions of 10 and

Table 1. Species and sources of fish

Common name

Rainbow trout.. 

Brown trout..... 

Brook trout....,

Lake trout

Channel catfish,

Bluegill

Smallmouth bass.. 

Largemouth bass..

Scientific name

Salmo gairdneri 

Salmo trutta 

Salvelinus fontinalis

Salvelinus namayacush

Ictalurus punctatus

Lepomis macrochirus

Micropterus dolomieui 

Micropterus salmoides

Source

NFH,]_/ Manchester, Iowa

SFH,2/ Lanesboro, Minn.

SFH, Lanesboro, Minn.

SFH, Osceola, Wis.

NFH, Jordan River, Charlevoix,

Mien.

SFH, St. Croix Falls, Wis. 

NFH, Fairport, Iowa 

NFH, Guttenberg, Iowa 

SFH, Lansing, Iowa 

NFH, Guttenberg, Iowa 

NFH, Lake Mills, Wis. 

NFH, Fairport, Iowa 

NFH, Genoa, Wis.

]_/ National Fish Hatchery 

2/ State Fish Hatchery
180 ppm of total hardness were prepared as 

described by Schoettger and Julin (1967) and 

contained 15 ppm of quinaldine. Ten fish were 

used to bioassay each test solution. Effects on 

efficacy were judged by the times to induce 

total loss of equilibrium (stage 11) in all fish.

The effect of repeated exposures to quinaldine was tested by treating ten 3 .6-inch rainbow 

trout daily in a concentration of 12 ppm at 12° C. 

The times to total loss of equilibrium (stage 11) 

and recovery, and the percent survival were 

used as indexes of sensitivity. After six consecutive treatments, the susceptibility of the 

fish was compared with that of untreated controls .

The potency of quinaldine solutions aged up 

to 50 days at 12° or 27° C. were determined by 

bioassay. The tests at 12° were conducted in 

polyethylene tanks containing 45 liters of a 15- 

ppm solution. Temperature was maintained 

within+2° C. by water baths, and at intervals 

efficacy was checked against ten 5-inch rainbow 

trout. Two-inch bluegills were used in bioassays 

at 27° since trout are difficult to maintain at this 

temperature. A level of 12 ppm was tested at 

27° because, at the time, effective concentrations had not yet been established for bluegills. The volume of some solutions at both 

temperatures was reduced during aging by 

evaporation, but oxygen levels were not 

seriously affected. Water losses were replaced 

with deionized water before the tests .

The quantity of fish which can be anesthetized per milliliter of quinaldine was estimated 

by narcotizing a number of 5-inch rainbow trout 

in the same solution until it became ineffective. 

The test was conducted in 2.5 liters of a 15-ppm 

solution which was aerated and maintained at 

12° C. Five individuals at a time were anesthetized to total loss of equilibrium (stage 11) 

removed, weighed, and placed in fresh water. 

None of the fish was exposed to the chemical 

more than once. The test solution was considered ineffective when, in consecutive trials, 

fewer fish were anesthetized.

The toxicity of quinaldine to fertilized eggs 

of rainbow trout was determined at concentrations of 15, 30, 60, and 120 ppm. Sixty to

70 eggs, 24 hours old, were placed in 2.5 liters 

of each concentration. Fifteen eggs were removed 

from each solution after 15, 30, 60, and 120 

minutes of exposure, rinsed, placed in petri 

dishes, and incubated in well water at 12° C. 

Four groups of control eggs were placed in reconstituted water without quinaldine and then 

incubated like the treated eggs . Mortalities 

among the quinaldine-treated and control eggs 

were recorded 96 hours after treatment, and 

thereafter at intervals until hatching.

RESULTS AND DISCUSSION

BEHAVIOR OF ANESTHETIZED FISH

The behavior of quinaldine-treated fish is 

different, in some respects, from that of fish 

exposed to other anesthetics (McFarland, 1960; 

Schoettger and Julin, 1966). At first, the chemical 

causes irritation which seems to increase in 

intensity with concentration. Shortly thereafter 

they lose equilibrium without entering a pronounced stage of sedation. Anesthesia progresses 

rapidly to total loss of equilibrium (stage 11) 

and then slows . At this level the fish are 

relatively motionless and may rest upright, 

inverted, or on their sides on the bottom of the 

container. They can be handled gently, but 

striking the container or squeezing the caudal 

peduncle or fin induces strong reflex movements. 

Bell (1964) indicated that quinaldine was useful 

for surgical operations on coho salmon, but in 

operations on rainbow trout we observed periodic 

reflex movements that hindered surgery.

Fish can be maintained in total loss of 

equilibrium, (stage 11) for relatively long 

periods, depending on concentration, before the 

onset of loss of reflex and medullary collapse. 

The loss of reflex stage appears to be practically 

nonexistent. Thus, loss of equilibrium is best 

suited for evaluating the efficacy of quinaldine.

The mode of action of quinaldine in fish is 

unknown. Bell (1964) suggested that it may act 

like the barbiturates as depressants on the 

central nervous system and especially the 

respiratory center. We measured opercular 

rates in anesthetized and control rainbow trout. 

The rate in the latter was approximately 60 per 

minute. In treated individuals the rate increased
to more than double the control value after 5 

minutes of exposure. Although the rate in 

treated fish was much faster, the opercular 

movements appeared weak and were interrupted 

by periodic gasps.

EFFICACY

Concentrations of 15 or 16 ppm were, in 

most instances, at least 90 percent effective for 

inducing anesthesia within 2 minutes in rainbow 

trout, brown trout, brook trout, and lake trout 

(table 2). The mean exposures tolerated by the 

trout ranged from 45 minutes to more than 6 

hours. Most individuals recovered in fresh 

water within several minutes, but some required 

over 60 minutes. Temperature and size of trout 

appear to have no influence on efficacy, or on 

exposure and recovery time.

As many as 25 percent of the test fish died 

in some trials (table 2). This was not delayed 

mortality, but resulted from attempts to 

measure the longest exposure tolerated by each 

test group. Since the fish could not be observed 

constantly during the experiments, the most 

susceptible individuals were overexposed. The 

procedure may have contributed to the long 

recovery times noted in some trials. However, 

the mortalities of trout should be minimal when 

the progress of anesthesia can be watched more 

closely.

Channel catfish, bluegills, and largemouth 

bass are more resistant at temperatures of 

17° C. and lower than are salmonids (table 2). 

Catfish were anesthetized by 70 ppm, bluegill 

by 15 to 60 ppm, and bass by 20 to 70 ppm. At 

22° or 27° C., about 15 ppm were effective on 

bluegill and bass, and 30 ppm narcotized catfish. 

The results show that 7- to 12-inch bass are 

much more resistant to quinaldine than smaller 

individuals.

The relatively high concentrations required 

to anesthetize catfish, bluegills, and bass at 

17° C. and below shortened the mean exposure 

and lengthened recovery time (table 2). In 

general, the fish tolerated exposure for about 

5 to 20 minutes at levels exceeding 15 ppm. At 

lower concentrations they commonly tolerated 

exposures of one to more than six hours.

Recovery time appeared to be more related to 

temperature and concentration than to exposure 

time, especially in bluegills and largemouth 

bass. For example, bluegills recovered in 2 to 

4 minutes after a 6-hour exposure to 15 ppm at 

27° C., whereas more than 60 minutes were 

required at 7° after a 0.4-hour exposure to 60 

ppm. This may indicate an effect of low tern - 

perature on the excretion or metabolic de - 

activation of quinaldine.

Effects of pH. --The efficacy trials shown 

in table 2 were carried out at pH 7.0 and 8.5. 

We combined the data since there appeared to 

be no difference in the results at these pH 

values. The trials at pH 5.0 gave quite different 

results. The drug was completely ineffective 

on all seven species. Further trials were 

carried out to determine the approximate degree of acidity which deactivated quinaldine. 

Nine smallmouth bass were anesthetized in a 

20-ppm solution at 12° C. and pH 7.0. The pH 

was changed to 5.0 and the fish recovered in 

20 to 25 minutes. In another experiment the 

pH was changed to 5.7, but the fish did not recover within a 2-hour period. Thus, a pH of 

about 6.0 or above does not deactivate quinaldine.

Acidic solutions apparently do not destroy 

quinaldine. Channel catfish were not affected 

by a 1 -hour exposure to either 50 or 60 ppm of 

the chemical &t pH 5.0. When the pH of the 

former solution was raised to 7.0, and that of 

the latter to 10.3, the fish were narcotized in 

3 to 10 minutes. This suggests that under acid 

conditions the quinaldine molecule shifts from 

an ionic to a non-ionic form which is less 

biologically active.

Effects of water hardness. - -Quinaldine was 

as effective on rainbow trout in soft water (10 

ppm total hardness) as in hard water (180 ppm 

total hardness). Four trials were run in soft 

water and two in hard water, and in each case 

all of the fish were anesthetized within 2 minutes.

Effects of repeated anesthetization. --Daily 

exposure of rainbow trout to 12 ppm of quinaldine 

for 6 days did not influence their sensitivity to the 

drug. The fish were anesthetized within 1 to 

3.5 minutes, and variations in efficacy appeared 

random. They were exposed to the chemical for
Table 2. Concentrations of quinaldine which anesthetize seven species of fish to total 

loss of equilibrium (staqe 11) within 2 minutes

Recovery

Concentration 

Species (ppm)

Rainbow 

trout... 

Do .....

Do.....

Do.....

Do.....

Brown 

trout. . . 

Do.. ... 

Do.....

Do.....

Brook 

trout. .. 

Do.....

Do.....

Do.....

Do.....

Lake 

trout. . . 

Do.....

Do.....

Do.....

Do ..... 

Do.....

Channel 

catfish. 

Do.. .. 

Do.....

Do.....

Do.....

Do.....

Do.....

Do.....

Do

Bluegill. . 

Do.....

Do.... . 

Do.....

Do.....

Do.....

Largemouth 

bass. . . . 

Do.....

Do.....

Do.....

Do.....

Do.....

Do.....

15 

15 

15 

15 

15 

16

16 

16 

16 

16 

16

16 

16 

16 

16 

16

15 

16 

15 

15 

15 

15

70 

70 

70 

70 

70 

30 

30 

30 

30

60 

30 

15 

10 

15 

15

30 

70 

15 

30 

20 

16 

15

Temper- Fish

ature

(° c.)

7° 

7° 

12° 

12° 

17° 

17°

7° 

12° 

12° 

12° 

17°

7° 

7° 

12° 

12° 

17°

7° 

7° 

7° 

12° 

12° 

17°

7° 

12° 

12° 

17° 

17° 

27° 

27° 

27° 

27°

7° 

12°

17° 

22° 

27° 

27°

7° 

7° 

12° 

12°

17° 

22 o

27°

Size Nt 

(in.) t(

2- 6 

7-12 

7-12 

7-12 

7-12 

7-12

7-12 

2- 6 

7-12 

7-12 

7-12

2- 6 

7-12 

2- 6 

7-12 

7-12

2- 6 

2- 6 

7-12 

2- 6 

7-12 

7-12

7-12 

2- 6 

7-12 

2- 6 

7-12 

2- 6 

7-12 

7-12 

7-12

2- 6 

2- 6 

2- 6 

2- 6 

2- 6 

2- 6

2- 6 

7-12 

2- 6 

7-12 

7-12 

2- 6 

2- 6

jmber

Fish in 

anesthesia

ssted (number)

45 

20 

20 

20 

25 

25

20 

10 

15 

5 

20

20 

20 

40 

20 

20

40 

30 

24 

100 

20 

24

42 

70 

30 

70 

10 

10 

5 

10 

5

37 

30 

20 

20 

30 

10

20 

5 

60 

70 

21 

20 

40

43 

19 

19 

20 

16 

25

20 

10 

15 

5 

20

20 

20 

35 

20 

20

35 

30 

24 

100 

20 

20

42 

70 

30 

70 

10 

10 

4 

10 

5

29 

28 

20 

20 

30 

10

19 

5 

59 

70 

19 

20 

39

Mean 

Exposure ! 

Time E:

(percent) (hrs.)

96 

95 

95 

100 

64 

100

100 

100 

100 

100 

100

100 

100 

88 

100 

100

88 

100 

100 

100 

100 

83

100 

100 

100 

100 

100 

100 

80 

100 

100

78 

93 

100 

100 

100 

100

95 

100 

98 

100 

90 

100 

98

0.8 

6.0

2.32/

6.0 

6.0 

3.0

6.0 

>6.0 

6.0 

4.0 

6.0

1.7

6.0 

1.0 , 

0.52 / 

6.0

1.0 

1.8 

6.0 

2.9 

6.0 

6.0

0.1

o.iV

0.1 

1.0 

6.0 

1.2 

>6.0

0.4 

0.3 

6.0 

0.3 

1.0 

6.0

1.8 

0.1

o'.l*/

2.5 

4.5

Safe 

xposure 

Index!/

24 

180

180 

180 

90

180 

^-180 

180 

120 

180

51

180 

30

180

30 

54 

180 

57 

180 

180

3 

3

3 

30 

180 

36 

>180

12 

9 

180 

9 

30 

180

54 

3 

54

75 

135

Mean 

time 

range Survival 

(min.) (percent)

6-13 100 

95 

1-4 100 

100 

3- 5 76 

5-43 76

13-23 100 

10 

5-8 100 

-c?5 100 

4- 6 100

3-21 80 

15-27 95 

3->60 88 

2- 4 100 

95

5-10 75 

1 0->60 90 

-^40 92 

2-15 98 

<30 90 

6-9 100

11-24 100 

5-11 100 

5- 6 100 

4-7 100 

3- 6 100 

3- 4 80 

«£5 100 

1-3 100 

1 100

>60 92 

12->60 100 

4-8 100 

20-35 100 

2-20 93 

2- 4 100

36->60 95 

4o->60 1 00 

10-33 92 

8-13 100 

6-29 95 

2- 3 95 

1-2 100

I/ Index obtained by dividing the time for the first fish to reach medullary collapse by the

time (2 minutes) for fish to reach total loss of equilibrium, stage 11. 

2/ Fish removed from the anesthetic before reaching medullary collapse.
periods of approximately 2 to 20 minutes, and 

all recovered in fresh water within 2 minutes . 

The response of fish receiving six treatments 

was essentially the same as those not treated 

previously.

Effects of aging.--The aging of quinaldine 

solutions at 12° C. appears to have little effect 

on efficacy. Concentrations of 15 ppm which 

were aged for 50 days anesthetized rainbow 

trout within 2.0 minutes . This compares 

favorably with the effectiveness of solutions bioassayed immediately after preparation. At 

27° C . quinaldine was less effective on bluegill 

after the solutions were aged for 21 days 

(table 3). These data show that solutions of the 

anesthetic should be usable over relatively long 

periods, unless fouled by mucous or excrement, 

but they may require aeration. We found that 

aeration for as long as 24 hours does not 

diminish efficacy.

Table 3.--Influence of aging on efficacy of 

12 ppm of quinaldine for b1uegi11s 

at 27° C.

Fish in loss

of equilibrium

Solution

age

(days)

0

1

3

7

14

21

21

Number

of

fish

10

10

10

10

10

10

10

stage

Number

10

10

10

10

10

0

4

11

Time

(Min.)

1.0-2.0

0.5-1.5

1.0-2.0

0.5-1.0

0.5-2.5

-

7.0-9.0

Recovery

in fresh

water

(number)

10

10

10

10

10

10

10

Repeated use of solutions. --The approximate "life expectancy" of quinaldine solutions 

was determined by anesthetizing groups of rainbow trout in a concentration of 15 ppm. A total 

of 3,542 grams of fish were treated in a solution 

containing 0.037 ml. of quinaldine before the 

exposure required for anesthesia exceeded 2 

minutes . This ratio of fish weight to quinaldine 

amounts to 94 .5 kg./ml. Meister and Ritzi 

(1958) made similar measurements for MS-222. 

They found that about 14 kg. of brook trout and 

42 kg. of lake trout could be effectively narcotized per gram of drug.

TOXICITY TO EGGS

Fifteen- to 30-minute exposures of fertilized rainbow trout eggs to concentrations as 

high as 120 ppm of quinaldine were apparently 

not detrimental (table 4). Two-hour exposures 

to concentrations of 60 and 120 ppm killed 

approximately 40 and 100 percent of the eggs 

respectively within 4 days, while mortalities 

at 15 and 30 ppm were relatively light. Some 

random mortalities occurred in the treated 

and control eggs throughout the balance of the 

incubation period. The remaining eggs hatched 

-approximately 21 days later. Since most 

spawning operations would probably be carried 

out with concentrations of 15 to 30 ppm, and 

since fertilized eggs are placed subsequently 

in flowing water, it is unlikely that accidental 

contamination of eggs would be detrimental.

Table 4.--The toxicity of quinaldine to

fertilized, rainbow trout eggs at 

12° C.

Concentration

(ppm)

Control

15

30

60

120

Number

of

eggs

60

15

15

15

15

Number of dead eggs within 4 

days after exposure to quinaldine for

0.25

hours

0

0

0

0

0

0.50

hours

0

0

0

0

0

1.00

hours

0

0

0

2

1

2.00

hours

0

1

1

6

15

METABOLISM OF QUINALDINE

The metabolism of quinaldine in fish has 

not been elucidated. Early investigations with 

other animals indicated that the chemical may 

be converted into natural metabolites. Kusui 

(1931) concluded that frogs oxidized a small 

portion of subcutaneously injected quinaldine 

to quinaldic acid which was excreted in the urine 

Takahashi (1931) reported that chickens and 

rabbits transformed the compound into alphaquinolinic acid, some of which was conjugated 

with glycine. Later studies have shown that 

relatively large amounts of 4 -methylquincline
(lepidin) are oxidized by chickens, but only 

trace quantities of 2 -methylquinoline (quinaldine) 

are changed to quinaldic acid (Tsunoo et al., 

1965). Quinaldic acid is a normal metabolite of 

tryptophan in various mammals and may be conjugated with glycine and excreted in the urine 

(Roy and Price, 1959; Kaihara, 1960; Kaihara 

and Price, 1961). Thus, even in homotherms, 

the metabolic fate of quinaldine is not well understood .

SUMMARY

Concentrations of 15 or 16 ppm of quinaldine 

rapidly induce total loss of equilibrium in trout. 

Fifteen to 30 ppm are effective on channel catfish, bluegills, and largemouth bass at temperatures of 22° and 27° C. At lower temperatures, 

concentrations up to 60 or 70 ppm are needed to 

achieve rapid anesthesia in the largemouth bass. 

Quinaldine solutions with a pH of 5 .0 failed to 

anesthetize fish, but efficacy was restored by 

increasing basicity. Water hardness, age of 

solutions, and repeated exposures of fish to 

quinaldine appear to have little influence on 

efficacy. The chemical is toxic to fertilized 

rainbow trout eggs only after several hours exposure to relatively high concentrations.

The utility of quinaldine as a fish anesthetic 

depends in large part on the needs of the fishery 

worker. Its major assets include rapid action 

and prolonged maintenance of anesthesia. On 

the other hand, anesthetized fish retain a degree 

of reflex responsiveness which may interfere 

with stripping, delicate surgical operations, and 

blood collection.

Kaihara, Masako.

1960. Studies concerning the metabolic fate 

of quinaldic acid-carboxyl-C^ . Journal 

of Biological Chemistry, vol. 235, no. 1, 

p. 136-139.

Kaihara, Masako, andj. M. Price.

1961. Quinaldylglycyltaurine: A urinary 

metabolite of quinaldic acid and kynurenic 

acid in the cat. Journal of Biological 

Chemistry, vol. 236, no. 2, p. 508-511.

Kusui, Kenzo.

1931. Zur Kenntnis der Vergleichenden 

Biochemie. VIII. Uber des Verhalten 

einiger heterocarbocyclischen Verbindungen im Froschorganismus. 

Journal of Biochemistry, vol. XIII, no. 2, 

p. 343-350.

Lennon, Robert E.

1967. Clearance and registration of chemical 

tools for fisheries. The Progressive 

Fish-Culturist, vol. 29, no. 4, p. 187- 

193.

McFarland, William N.

1960. The use of anesthetics for the handling 

and the transport of fishes. California 

Fish and Game, vol. 46, no. 4 , p. 4 07 - 

431.

Meister, Alfred L., and Charles F. Ritzi. 

1958. Effects of chloretone and MS-222 on 

eastern brook trout. The Progressive 

Fish-Culturist, vol. 20, no. 3, p. 104- 

110.

REFERENCES

Bell, Gordon R.

1964 . A guide to the properties, characteristics , and uses of some general 

anesthetics for fish. Fisheries Research 

Board of Canada, Bulletin 148. 4 p.

Greenough, Edward E.

1963. Fish preservation. United States 

Patent Office, patent no. 3, 110, 285. 

4 P.

Muench, Bruce.

1958 . Quinaldine, a new anesthetic for fish. 

The Progressive Fish-Culturist, vol. 20, 

no. 1, p. 4 2 -44 .

Natarajan, M. V., andV. Ranganathan.

1960. A note on the possibilities of utilizing 

quinaldine in transporting live fish. 

Current Science, vol. 29, no. 10, p. 393,

Penfold, Vincent F.

1965. An anesthetic fish-collecting chemical, 

Presented at the American Society of Ichthyologists and Herpetologists Aquarium 

Symposium, Chicago, June 13-15. 1 p.
Roy, J. K., andj. M. Price.

1959. The identification of quinoline

derivatives obtained from the urine of 

normal rabbits and swine. Journal of 

Biological Chemistry, vol. 234, no. 10, 

p. 2,759-2,763.

Schoettger, Richard A.

1967. Investigations in Fish Control: 16. 

Annotated bibliography on MS-222. U.S. 

Bureau of Sport Fisheries and Wildlife, 

Resource Publication 22, 15 p.

_______, 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.

Spector, William S.

1956. Handbook of toxicology. Volume 1. 

Acute toxicities of solids, liquids and

gases to laboratory animals. W. B. 

Saunders Co., Philadelphia, 408 p.

Takahashi, Masao.

1930. Zur Kenntnis^der Vergleichenden 

Biochemie. V. Uber das Verhalten des 

Chinaldins im Organismus des Kaninchens und des Huhns. Journal of Biochemistry, vol. XI, no. 3, p. 437-439.

Tsunoo, Shigeru, Kazuyoshi Horisaka, Shigeru

Sasaki, andKusuo lida.

1965. Uber die Entgiftungsvorg'ange der 

heterocarbocyclischen Verbindungen 

im Huhnerorganismus. Japanese Journal 

of Pharmacology, vol. 15, p. 149-156.

Turner, Francis M.

1950. The Condensed Chemical Dictionary. 

4th edition. Reinhold Publishing Corporation, New York. 726 p.

10
INVESTIGATIONS IN FISH CONTROL

23. Toxicity of Quinaldine 

to Selected Fishes

By Leif L. Marking, Chemist

UNITED STATES DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

Bureau of Sport Fisheries and Wildlife 

Washington, D.C. January 1969
CONTENTS

Page 

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

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

Results ........ ....................... 5

Species and sizes of fish ................... 5

Effects of temperature .................... 5

Effects of water quality ..................... 5

Recovery ........................... 7

Safety indexes ........................ 8

Discussion ............................ 8

Conclusions ............................ 9

References ............................ 10
TOXICITY OF QUINALDINE TO SELECTED FISHES

By Leif L. Marking, Chemist 

Bureau of Sport Fisheries and Wildlife 

Fish Control Laboratory, La Crosse, Wisconsin

ABSTRACT.--Quinaldine, an anesthetic for fish, is toxic to 

various sizes of rainbow trout, brown trout, brook trout, lake 

trout, northern pike, channel catfish, bluegills, largemouth bass, 

and walleyes in 15-, 30-, and 60-minute and 3-, 6-, 24-, 48-, and 

96-hour static bioassays. Toxic concentrations range from 2.0 to 

25 ppm in standard tests at 12° C . in 96 hours . Its toxicity to rainbow trout is significantly greater at higher temperatures, and 96- 

hour LCSO's range from 13.3 ppm at 7° to 1.9 ppm at 17° C. In 

6-hour exposures, quinaldine is more toxic at colder temperatures. 

Bluegills are more sensitive at 22° than at 12° or 17° C. The 

anesthetic is more toxic to fish in hard than in soft water, a condition probably associated with pH. Safety indexes show that 

shorter exposures to quinaldine are safer to fish, although the concentrations may be greater than required in longer exposures . 

Recovery from anesthesia is good among survivors in fish exposed 

to partial-kill concentrations of quinaldine for 96 hours.

Anesthetics are rapidly becoming more important and widely used in fisheries. Varieties 

of anesthetics have been found useful in marking, 

tagging, transporting, and spawning fish of 

various species (Parkhurst and Smith, 1957; 

McFarland, 1960; Bell, 1964). Practical concentrations of chemicals to produce desirable 

anesthesia in fish have been defined under field 

conditions by several workers (Meister and 

Ritzi, 1958; Thompson, 1959). Klontz(1964) 

outlined 14 methods used to anesthetize fish.

Quinaldine was reported to be an anesthetic 

for fish by Muench (1958). More recently, 

Matarajan and Ranganathan (1960) and Greenough (1963) discussed the usefulness of quinaldine in fisheries . A comprehensive study of 

$he compound's efficacy as an anesthetic for 

seven freshwater fish species was made by 

Schoettger and Julin (1968).

Quinaldine (2-methylquinoline) occurs in 

coal tar. It can be manufactured by treatment 

of aniline and paraldehyde with hydrochloric acid 

and heat (Rose and Rose, 1966) or derived from 

aniline, acetaldehyde, and hydrochloric acid 

(Stecher et al., 1960). Quinaldine boils at 246° - 

247° C., darkens from light yellow to brown with 

exposure to air, is soluble in alcohol, ether, 

chloroform, and acetone, but is insoluble in 

water (Rose and Rose, 1966).

This study was undertaken to establish the 

toxicity of practical-grade quinaldine to nine 

species of fish.

METHODS AND MATERIALS

Nine species of fish were obtained from fish 

hatcheries (table 1). Three size groups included 

1- to 3-inch, 3- to 5-inch, and 6- to 9-inch fish.
Table 1. Fishes used in tests of quinaldine

Common name

Rainbow trout.. 

Brown trout.... 

Brook trout.... 

Lake trout.....

Northern pike..,

Channel catfish, 

Bluegi11........

Largemouth bass, 

Walleye.........

Scientific name

Salmo gairdneri 

Salmo trutta 

Salvelinus fontinalis 

Salvelinus namaycush

Esox lucius

Ictalurus punctatus 

Lepomis macrochirus 

Micropterus salmoides 

Stizostedion vitreum

Source

NFH, Manchester, Iowa

NFH, Manchester, Iowa

SFH, Osceola, Wis.

NFH, Jordan River, Mich.

SFH, St. Croix Falls, Wis,

NFH, Garrison Dam, N. D.

NFH, Gavins Point, S. D.

NFH, Fairport, Iowa

NFH, Lake Mills, Wis.

NFH, Genoa, Wis.

NFH, Garrison Dam, N. D.

Ten fish were included at each of 10 or 11 concentrations of quinaldine in 15-liter, static bioassays as described by Lennon and Walker 

(1964). Ten to twenty of the 1 - to 3 -inch fish 

served as controls depending on how many concentrations were tested. The bioassays with 3- 

to 5-inch and 6- to 9-inch fish were made in 

polyethylene tanks containing 45 liters of 

aerated solution. Five concentrations were 

tested against the 9-inch fish, and 10 fish 

served as controls.

Variations in water quality were arranged 

by adding different amounts of reconstituting 

salts to deionized water (table 2). Temperatures of 7° , 12° , 17° , and 22° C. were maintained by placing the bioassay vessels in thermostatically controlled water baths. All 

temperatures listed hereafter are in Centigrade.

Concentrated stock solutions of the practical-grade quinaldine manufactured by Eastman Organic Chemicals were mixed daily to 

insure complete activity and prevent degradation. Acetone was used to dissolve 7.5 milliliter 

of quinaldine and this was diluted with deionized 

water. Approximately 50 percent of the final 

250 milliliter of stock volume was water.

Fish responses to quinaldine were recorded 

for several hours after exposure and daily thereafter throughout the 96-hour bioassay. Dead 

fish were recorded and removed. Live fish were 

readily distinguishable because they were hypersensitive to sound and vibrations up to the.time 

of death. Fish which remained in anesthesia 

throughout a test were placed in fresh water 

until they recovered. The times for recovery 

and survival were noted.

The toxicity data were analyzed according 

to the methods of Litchfield and Wilcoxon (1949) 

to determine LCSO's, variations, slope functions, 

and 95 percent confidence intervals.

Safety indexes were calculated to determine 

the margin of safety between efficacious and 

lethal concentrations of quinaldine. The values

Table 2. Quantities of salts added to deionized water at the Fish Control Laboratories

Classification 

of

water

Soft......

Standard!/ 

Medium. . . . 

Hard......

NaHC03

12 

kQ 

192

Salt added

7.5 

30.0 

120.0 

2ifO.O

in mg./l .

MgSO^

7.5 

30.0 

120.0 

2kO.Q

KCL

0.5 

2.0 

8.0 

16.0

Concentration 

as ppm CaCOo

PH 

range

7.2-7.6 

7.6-8.0 

8. 0-8. ^

Total 

hardness

10-13

160-180 

280-320

Total 

Alkalinity

10-13 

30-35 

110-120

Standard reconstituted water used in routine bioassay
derived are the quotients of effective and lethal 

concentrations.

RESULTS

SPECIES AND SIZES OF FISH

Quinaldine is toxic to coldwater and warmwater fish in 96-hour exposures, and LCSO's 

range from 2.0 to 24 .9 ppm (table 3). Channel 

catfish are the most resistant species irrespective of size and duration of exposure. Northern 

pike show a decreased resistance between 

LCSO's of 20 ppm at 24 hours and 2 ppm at 96 

hours . The decrease may be attributed to a 

combination of starvation and quinaldine intoxication. This species demands a large and 

constant supply of food, but none is supplied in 

the bioassay.

The small sizes of rainbow trout, brown 

trout, lake trout, channel catfish, and large - 

mouth bass are more sensitive to quinaldine 

than large individuals, particularly at 96-hour 

exposures (table 3). The LC50 for 2-inch rainbow trout, for example, is 5.0 ppm while the 

LC50 for 6-inch fish is 15.3 ppm; and the 

LCSO's for 2- and 6-inch brown trout are 3 .5 

and 14 .0 ppm, respectively.

The 2-inch rainbow trout are more resistant 

at 24 and 48 hours in exposures to quinaldine, 

than at 96 hours. Two-inch brown trout respond 

similarly. The LCSO's for lake trout, on the 

other hand, do no vary significantly between the 

48- and 96-hour exposures.

The toxicity of quinaldine was relatively 

uniform to brook trout of the sizes tested. 

Larger individuals appeared to be more sensitive, 

but also had become infected with furunculosis 

just prior to the bioassays. The added stress 

factor may explain these results . The disease 

in these fish was diagnosed following the tests. 

In general, brook trout resistance to the anesthetic was similar to that of the larger rainbow 

and brown trout.

EFFECTS OF TEMPERATURE

In 1- to 6-hour tests at 7° , 12° , and 17° , 

rainbow trout are more resistant to the toxic

effects of quinaldine at 17° than at 12° or 7° 

(table 4). This relationship is reversed at 24 

hours, and rainbow trout are more sensitive 

at 17° . The 1- and 96-hour LCSO's range from 

17.8 to 13.3 ppm at 7° and from 23.8 to 1.9 ppm 

at 17° . The 96-hour LCSO's show significant 

differences intoxicity.

Rainbow trout temperature tests were 

repeated several times since survival and mortality were erratic and results were difficult to 

analyze statistically. The 12° test in table 4 , 

for instance, indicates 50-percent mortality at 

5 ppm. Concentrations of 6 to 12 killed all test 

animals while one often survived 14, 18, and 

20 ppm at 96 hours. These data indicate that 

quinaldine is inconsistent in its toxic effects at 

high concentrations.

Higher temperatures of 12° , 17° , and 22° 

were used to determined the effects of quinaldine 

on bluegills (table 5). The LC50 of 10.1 ppm for 

24, 48, and 96 hours indicates that exposures 

over 24 hours do not increase the toxicity. The 

effect of exposure was also small at 17° but 

bluegills are more resistant than at 12° or 22° . 

The toxicity of quinaldine at 22° increases significantly at 96 hours exposure and bluegills die at 

approximately 6 ppm.

EFFECTS OF WATER QUALITY

Quinaldine toxicity to 2-inch rainbow trout 

is essentially the same in standard and medium 

quality water after 1, 3, 6, and 96 hours exposure (table 6). Quinaldine is significantly less 

toxic in soft water, however, in 1- to 6-hour 

exposures. It is also less toxic in soft water at 

96 hours, but the difference in soft, standard, 

and medium water quality is .not significant at 

this time interval. Toxicity increases with exposure time at every water quality.

Rainbow trout survival in soft and medium 

quality water was erratic and some fish lived in 

surprisingly high concentrations of drug. In 

water of medium hardness one trout survived 

20 ppm of quinaldine, but none survived concentrations between 6 and 20 ppm. In soft water one 

trout survived 18 ppm of the anesthetic while 

none survived concentrations between 8 and 18 ppm 

Survival occurred at the higher concentrations,
Table 3.--Toxicity of quinaldine to fish at 12° C.

Species 

Rainbow trout....

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

DO...........O

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

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

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

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

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

Northern pike.... 

Channel catfish.o 

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

Bluegi 11 .........

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

Largemouth bass. . 

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

Average 

weight 

(grams)

1.0 

23.0 

2.6 

14.3 

27.0 

12.5 

20.0 

37.5 

2.0 

5.6 

35.0 

1.8 

1.9 

5.2 

1.3 

2.8 

0.5 

5.2

Approximate 

length 

(inches)

2 

6 

2 

4 

6 

3 

4 

6 

2 

3 

7 

2

3 

if 

2

3 

1 

if

LC50 (ppm) and 95 percent confidence interval at

2if 

hours

18.7 

18.2-19.2

16.0 

lif. 2-18.1

13.0 

10.9-15.5

18.0 

15.3-21.2

15.0 

13.6-16.5

14.5 

13.1-16.1

15.0 

13.2-17-1

13.2 

12.5-14.0

6.8 

5.8-8.0

14.2 

13.^-15.1

13.0 

12.1-13-9

20.0 

18.8-21.2

21.0 

19.3-22.9

29. if 

28.3-30.6

10.1 

9.4-10.8

12.8 

12.2-13.4

10.4 

9.7-11.1

10.4 

9.8-11.0

48 

hours

17.8 

16.4-19.3

15.3 

13.9-16.8

9.0 

6.0-13.5

17.0 

14.9-19.4

14.8 

13.5-16.3

14.0 

12.8-15.3

14.0 

13.1-15.0

12.4 

11.4-13.5

5.6 

5.0-6.3

13.5 

12.4-14.7

12.6 

11.7-13-6

8.0 

6.3-10.2

20.0 

18.2-22.0

27.4 

25.6-29.3

10.1 

9.4-10.8

12.8 

12.2-13.4

9.4 

8.5-10.3

9.9 

9.3-10.5

96 

hours

5.0 

4.5-5.6

15.3 

13.9-16.8

3.5 

2.1-5.9

16.0 

14.7-17-4

14.0 

12.7-15.4

13.6 

12.5-14.8

13.5 

12.6-14.4

12.0 

10.7-t3.4

5.6 

5.0-6.3

13.5 

12.4-14.7

12.3 

11.3-13.4

2.0 

1.1-4.6

19.9 

18.1-21.9

24.9 

23.3-26.6

10.1 

9.4-10.8

12.6 

11.8-13.5

4.6 

3.5-6.1

6.5 

5.6-7.5
(continued) Table 3. Toxicity of quinaldine to fish at 12° C.

Species

Largemouth bass..

Average 

weight 

(grams)

63.0 

0.7

Approximate 

length 

(inches )

7 

2

LC50 (ppm) and 95 percent confidence interval at

2k 

hours

10.0 

8.8-11.3

10.1 

9.4-10.9

48 

hours

9.7 

8.7-10.9

10.1 

9.3-11.0

96 

hours

9.0 

7.7-10.5

9.8 

8.9-10.8

Table 4. Toxicity of quinaldine to rainbow trout at three temperatures

Temperature 0 C.

7°.....

12°..

17°.....

LC50 (ppm) and 95 percent confidence interval at

1 hour

17.8 

16.2-19.**

19.8 

18.8-20.8

23.8 

21.5-25.^

3 hours

16.1 

15.6-16.7

19.8 

18.8-20.8

23.8 

21. 5-25.^

6 hours

16.1 

15.6-16.7

19.8 

18.8-20.8

23.0 

20.3-26.0

24 hours

15.5 

14.3-16.8

18.7 

18.2-19.2

8.0 

6.2-10.1

48 hours

14.2 

12.6-15.9

17.8 

16.4-19.3

3.2 

2.3-4.5

96 hours

13.3 

11.9-14.9

5.0 

4.5-5.6

1.9 

1.5-2.3

Table 5.--Toxicity of quinaldine to bluegills at three temperatures

Temperature 

0 C.

12°....

17° i / ....

22° £~£- . » . .

LC50

24 

hours

10.1 

9.4-10.8

12.5 

11.9-13.1

11.3 

10.6-12.1

(ppm) and 95 percent confidence

48 

hours

10.1 

9.4-10.8

11.8 

10.9-12.7

11.0 

10.0-12.1

interval at

96 

hours

10.1 

9.4-10.8

11.6 

10.7-12.5

5.8 

5.6-6.0

but mortality was not erratic or unusual at the 

lower end of the lethal range. The trials in 

various water qualities were repeated several 

times to confirm the variations in survival.

RECOVERY

Fish exposed to sublethal concentrations of 

quinaldine usually recovered from anesthesia 

in the test vessel within the 96-hour bioassay.

Anesthesia progresses to partial or total loss of 

equilibrium within 15 to 30 minutes. The effects 

remain for 3 to 6 hours and then diminish. Intermediate concentrations produced anesthesia much 

faster and killed fish at progressively higher 

concentrations. Fish surviving the partial kill 

range, but still in deep anesthesia at 96 hours, 

were removed to fresh water and recovery was 

noted. Recovery was considered complete when 

the fish could swim against a current.
Table 6.--Toxicity of quinaldine to rainbow trout in selected water qualities at 12° C,

Water 

quality

Soft

I/ 1 hour

95. n

21.8-28.7

Standard. 19.8 

18.8-20.8

Medium... 19.1 

17.4-21.0

Hard...-- 91.1

I/Water

18.5-24.0

LC50 (ppm) and 95 percent confidence interval at

3 hours

25.0 

21.8-28.7

19.8 

18.8-20.8

18.5 

16.9-20.3

20.9 

18.4-23.8

qualities correspond to table

6 hours

24.1 

20.8-27.8

19.8 

18.8-20.8

18.4 

16.9-20.1

20.9 

18.4-23.8

2.

24 hours

19.0 

17.1-21.2

18.7 

18.2-19.2

16.7 

15.2-18.3

17.2 

13.8-21.5

48 hours

17.0 

15.3-18.8

17.8 

16.4-19.3

14.5 

12.6-16.7

9.9 

6.8-14.4

96 hours

5.1

4.4-6.0

5.0 

4.5-5.6

4.6 

4.2-5.1

4.3 

3.7-5.0

Northern pike and channel catfish which 

survive partial kill concentrations appear to 

recover faster than the other species and without additional mortality (table 7). The partial 

kill concentrations for these species are 

relatively high. Considering all species, the 

recovery is approximately 95 percent after 96- 

hour exposures, and all except bluegills recover 

quite rapidly. Occasionally one or several of a 

group will require longer periods. This fact 

was noted especially among lake trout and 

largemouth bass.

SAFETY INDEXES

The safety indexes for rainbow trout indicate greater safety in 15-minute exposures 

than in 30- or 60-minute exposures (table 8). 

The EC50 refers to the concentration of quinaldine producing total loss of equilibrium in onehalf of the specimens. This stage and other 

stages of anesthesia are described by Schoettger 

and Julin( 1967).

The maximum safety index is based on 

concentrations producing 99-percent effective 

anesthesia (EC99) and 1-percent mortality 

(LC1). These values were extrapolated from 

the regressions used in determining the EC50 

and LC50. The maximum safety index is lower 

than the safety index and is biased in favor of 

greater safety. Maximum safety indexes also 

indicate greater safety in 15-minute exposures 

(table 8). Indexes for 30- and 60-minute 

exposures are 0.9 and 1.0 and appear marginal

for practical applications of quinaldine. Values 

less than 1.0 indicate that one must expect mortality if 99 percent of the fish are anesthetized.

DISCUSSION

When the toxicities of quinaldine and MS-222, 

another fish anesthetic are compared, it is 

apparent that both drugs elicit similar patterns 

of toxic response among various species and 

sizes of fish. Previous research indicates that 

channel catfish are more resistant than other 

species to quinaldine and MS-222 (Marking, 

1967, and Schoettger et al. 1967). Smaller 

sizes of fish are generally more sensitive to the 

anesthetics, and rainbow trout respond erratically in waters of various qualities. Among the 

trout, lake trout are more sensitive to both 

anesthetics. The drug safety indices indicate 

that shorter exposures are safer and minimize 

mortality.

Actually, quinaldine is more toxic to fish 

than MS-222. The LCSO's for quinaldine range 

from 2.0 to 24 .9 ppm while those for MS-222 

range from 32.0 to 62.1 ppm for all species 

tested in 96-hour exposures at 12° . However, 

quinaldine is effective as an anesthetic at lower 

concentrations than MS-222 so that the safety 

indexes for both are quite similar.

In contrast with MS-222 quinaldine is more 

toxic at colder temperatures to 2-inch rainbow 

trout in 1- to 6-hour exposures. Lethal intoxication is not apparent in brief exposures at 

warmer temperatures, but toxic effects are
Table 7. Recovery from anesthesia of fish exposed to concentrations of quinaldine causing 

partial kills within 96 hours at 12° C.

Species 

(all sizes)

Rainbow trout ..

Northern pike... 

Channel catfish. 

Bluegi'11. .......

Largemouth bass.

Ufa 1 1 pwp

Partial 

kill

concentration 

(ppm)

5-16 

1-16

10-16

6-14

10-24 

12-36 

9-14

2-11 

3-10

Number

Surviving 

at 96 hours

105 

53

43

24

24 

97 

73

68

 aft 30

of fish

Recovering 

after 96 hours

102 

49

42

21

24 

97 

71

60 

35

Minutes to

recover in 

fresh water

2-60 

4-90

3-60

4-120

5-35 

4-16

1 Q 7C

5-120 

5-60

Table 8. Safety and maximum safety indexes of quinaldine against 2-inch rainbow trout in 

brief exposures at 12° C.

Exposure

(minutes)

15....

30....

60....

LC50 (pprn)

35.2

25.2

22.4

Safety index

EC50 (ppm)

13.6

14.0

13.3

LC50/EC50

2.6

1.8

1.7

Maximum safety index

LC1 (ppm) EC99 (ppm)

25.0 20.0

18.5 20.0

17.0 16.4

LC1/EC99

1.3

0.9

1.0

manifest after 24 hours. Quinaldine is also 

more toxic to bluegills at higher temperatures 

but only after 48 hours of exposure.

Quinaldine is less toxic to 2-inch rainbow 

trout in soft than in harder waters . Marking 

(1967) found little difference in the toxicity of 

MS -222 to rainbow trout at various water 

hardnesses. The low salt content and correspondingly low pH value of the soft water 

apparently affect the activity of quinaldine. 

Schoettger and Julin (1968) observed the effects 

of pH on quinaldine and noted that the drug is 

completely ineffective on fish at pH 5° . These 

data agree with the decreased toxicity of 

quinaldine in soft water.

CONCLUSIONS

Quinaldine is toxic to fish, and the 96-hour 

LCSO's for nine species range from 2.0 to 

24 .9 ppm. Channel catfish are the most resistant to the drug.

The anesthetic is more toxic to small fish, 

especially at 96 hours exposure. It is also more 

toxic to small rainbow trout and bluegills at 

higher temperatures in the longer exposure 

period.

Small rainbow trout respond erratically to 

the toxicity of quinaldine at various temperatures 

and water qualities . The fish are more resistant 

to the drug at higher temperatures in 1 - to 6 -hour 

exposures but less resistant in 24- to 96-hour exposures. They are also more resistant to the 

anesthetic in soft water than iji harder waters.

The safety indexes for quinaldine on fish 

indicate that brief exposures are safer for the 

fish and minimize mortalities.

Recovery from anesthesia is good among 

survivors exposed to partial-kill concentrations 

of quinaldine for 96 hours. The recoveries of 

nine species in fresh water occur within 2 to 120 

minutes. The process of recovery from anes - 

thesia in static test solutions begins during the 

bioassay after 6 hours of exposure.
REFERENCES

Bell, Gordon R.

1964. A guide to the properties, characteristics , and uses of some general 

anesthetics for fish. Fisheries Research Board of Canada, Bulletin no. 148, 

4 p.

Greenough, Edward E.

1963. Fish preservation. United States 

Patent Off ice, patent no. 3, 110, 285. 

4 p.

Klontz, George W.

1964. Anesthesia of fishes. From: Proceedings of the Symposium on Experimental Animal Anesthesiology, Brooks 

Air Force Base, December 14-16. 13 p.

Lennon, Robert E., 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.

Litchf ield, 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.

Marking, Leif L.

1967. Investigations in Fish Control: 

Toxicity of MS-222 to selected fishes. 

U.S. Bureau of Sport Fisheries and 

Wildlife, Resource Publication 18. 10 p.

McFarland, William N.

1960. The use of anesthetics for the handling 

and the transport of fishes . California 

Fish and Game, vol. 46, no. 4, p. 407- 

431.

Meister, Alfred L., and Charles F. Ritzi. 

1958 . Effects of chloretone and MS-222 on 

eastern brook trout. The Progressive 

Fish-Culturist, vol. 20, no. 3, p. 104- 

110.

Muench, Bruce.

1958. Quinaldine, a new anesthetic for fish. 

The Progressive Fish-Culturist, vol. 20, 

no. 1. p. 42-44 .

Nararajan, M. V., andV. Ranganathan.

1960. A note on the possibilities of utilizing 

quinaldine in transporting live fish. Current 

Science, vol. 29, no. 10, p. 393.

Parkhurst, Z. E., and M. A. Smith.

1957. Various drugs as aids in spawning 

rainbow trout. The Progressive FishCulturist, vol. 19, no. 1, p. 39.

Rose, Arthur, and Elizabeth Rose.

1966. The condensed chemical dictionary. 

7th edition. Reinhold Publishing Corporation, New York. 1,044 p.

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.

1968. Investigations in Fish Control: 22. 

The efficacy of quinaldine as an anesthetic 

for seven species of fish. U.S. Bureau 

of Sport Fisheries and Wildlife, Resource 

Publication.

_______, Charles R. Walker, Leif L. Marking,

and Arnold M. Julin.

1967. Investigations in Fish Control: MS-222 

as an anesthetic for channel catfish: Its 

toxicity, efficacy, and muscle residues . 

U.S. Bureau of Sport Fisheries and Wildlife, Resource Publication 33. 14 p.

Stecher, Paul G., M. J. Finkel, O. H. Siegmund,

and B. M. Szafranski.

1960. The Merck index of chemicals and drugs, 

Seventh edition. Merck and Company, 

Incorporated, Rahway, New Jersey. 

1,641 p.

Thompson, R. B.

1959. Tricaine methanesulfonate (MS-222) 

in transport of cutthroat trout. The 

Progressive Fish-Culturist, vol. 21, 

no. 2, p. 96.

10
INVESTIGATIONS IN FISH CONTROL

24. Quirmldine as an Anesthetic 

for Brook Trout, Lake Trout, 

and Atlantic Salmon

By David 0. Locke

UNITED STATES DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

Bureau of Sport Fisheries and Wildlife 

Washington, D.C. January
CONTENTS

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

Materials and methods ............... 3

Results ....................... 4

Conclusions .................... 5

References ..................... 5
QUINALDINE AS AN ANESTHETIC FOR BROOK TROUT, 

LAKE TROUT, AND ATLANTIC SALMON

By David O. Locke 

Maine Department of Inland Fisheries and Game, Augusta

ABSTRACT.--Quinaldine (2-methylquinoline) was an effective anesthetic for yearling Atlantic and landlocked salmon and brook and lake 

trout in waters ranging from 10 to 40 ppm total hardness and temperatures ranging from 36° to 40° F. and from 47° to 59° F. Lake trout 

were more sensitive than the other species tested. In tests, anesthetization and recovery rates for five concentrations (5, 10, 15, 20, 

and 25 ppm) at both temperatures (10 ppm) was generally satisfactory 

for lake trout. A concentration of 15 ppm was satisfactory for marking 

and general handling of salmon and brook trout. Quinaldine is one 

twenty-fourth as expensive as MS-222 at 1:12,000, and in view of our 

excellent results this drug warrants wider use as a fish anesthetic.

The comparatively high cost of the popular 

MS-222 as an anesthetic for fish has prompted 

many fishery workers to consider less costly 

drugs as substitutes. This paper reports on 

tests of quinaldine for anesthetizing several 

coldwater fishes. Quinaldine (2 -methylquinoline) 

is currently available in practical grade from 

Distillation Products Industries, Division of 

Eastman Kodak Company, at $14 .35 per 500- 

gram bottle. Quinaldine is also used in the 

manufacture of dyes and explosives. It has not 

been used in medicine as have other quinolines, 

but according to Muench (1958) it may have some 

antiseptic value. The exact mode of action of 

quinaldine on fish is unknown, but it supposedly 

acts like barbiturates, depressing the central 

nervous system, especially the respiratory 

center.

Although quinaldine is used extensively by 

fishery workers as an anesthetic, little has 

been published on its use. Muench (1958) reported its use on green sunfish, white crappie, 

yellow bullhead, golden shiner, and goldfish. 

Leitritz (1962) mentioned that the concentrations used range from 5 to 12 ppm. Bell 

(1964) recommended doses of 6.6 to 10 ppm for 

10-inch coho salmon. We decided to determine 

the usefulness of quinaldine for anesthetizing 

the commonly handled salmonids in the soft 

waters found in Maine.

I wish to thank Donald F. Mairs for his 

assistance and advice. Dr. W. Harry Everhart, 

Robert E . Foye, and Robert S . Rupp critically 

reviewed the manuscript and made many helpful 

suggestions.

MATERIALS AND METHODS

A stock solution was prepared by mixing 

37.85 milliliter of quinaldine with 40 milliliter 

of acetone and enough distilled water to make 

1 liter. The stock solution maintains its 

effectiveness for long periods when stored in 

brown bottles. One milliliter of stock solution 

added to 1 gallon of water gives a concentration 

of 10 ppm.

Tests were conducted on yearling Atlantic 

and landlocked salmon (Salmo salar), brook trout 

(Salvelinus fontinalis), and lake trout (S. namaycush) 

in waters ranging from 10 to 40 ppm total hardness and at temperatures ranging from 36° to 

40° F. and from 47° to 59° F . Five concentrations 

were tested: 5, 10, 15, 20, and 25 ppm. Each 

test was performed in duplicate. Control fish 

were handled exactly the same as test fish except that they were placed in containers of untreated fresh water. Each test consisted of 

placing six fish in a Fernow pail containing 5 

gallons of solution. We recorded the time required for fish to recover from anesthesia by
placing them in wash tubs containing 5 gallons 

of fresh water. All fish, including the controls, 

were fin-clipped for identification and subsequently held in raceways for 2 weeks to observe 

delayed mortality.

Each fish was considered anesthetized when 

it remained quietly on the bottom of the pail and 

exhibited no movement other than respiration 

and an occasional flexure of the caudal fin. Recovery was considered complete when the fish 

righted itself and maintained its equilibrium. 

Anethetization time was recorded for the first, 

third, and last fish. Each treatment was terminated after the fish had been in the test 

solution for 15 minutes. All fish were then 

placed in fresh water, and recovery time of the 

first, third, and last fish was recorded.

RESULTS

Anesthetization and recovery rates of 

different kinds and sizes of fish were directly 

proportional to the concentration of quinaldine 

in both temperature ranges (figs. 1 -4). 

Generally the fish were anesthetized quicker at 

the higher temperature and also recovered 

sooner than at the lower temperature. The 

greatest contrast in rate of anesthetization 

relative to concentration occurs at the lower 

temperatures. It takes 5 to 7 times as long to 

anethetize brook trout at 5 ppm than at 10 or 

15'ppm at 36° F . Although the efficacy was not 

affected to this degree on the other species, the 

5 ppm concentration did not provide dependable 

and speedy anethetization for these ranges in 

temperature.

25r

36° F AVE. LENGTH-6.3 INCHES 

ANESTHETIZATION ° 

RECOVERY o o 

59° F AVE. LENGTH-75 INCHES 

ANESTHETIZATION 

RECOVERY ~ 

25

20 

1

a.

z 15

O

1

0

o 

o

5

-

/ /

' / 7

f f

4 *

/. / 0

/ y

X S 40° F AVE. LENGTH-45

k / o X ANESTHETIZATION o 

^. s' S~ RECOVERY <> < 

^C»^< 48° F AVE. LENGTH -5.3

' ° * ANESTHETIZATION 

RECOVERY 

INCHES

 o

INCHES

 .

6 8

MINUTES

10

25r

37° F AVE. LENGTH-6.2 INCHES 

ANESTHETIZATION » » 

RECOVERY <> o 

48° F AVE. LENGTH-57 INCHES 

ANESTHETIZATION 

RECOVERY - 

6 8 

MINUTES

10

38°F AVE. LENGTH - 5.2 INCHES 

ANESTHETIZATION o «, 

RECOVERY o-- o

47°F AVE. LENGTH- 5.8 INCHES 

ANESTHETIZATION 

RECOVERY 

6 8 

MINUTES

10

Figure 1. Effect of quinaldine on brook trout (top left), lake trout (top right), Atlantic 

salmon (bottom left), and landlocked salmon (bottom right) at two temperature levels. Reported times are averages of two trials and indicate the anesthetization and recovery of 

one-ha«lf of the test fish.
The muscles of anesthetized fish became 

relaxed and the fish did not respond to gentle 

handling. Rough handling and sudden disturbances sometimes caused the anesthetized 

fish to swim a short distance and then come to 

rest again. Larger fish appeared to be more 

deeply narcotized than smaller ones.

The respiration rate of effectively anesthetized fish appeared to be more rapid than 

that of the control fish. Opercular movements 

were slight. Respiratory movements did not 

cease among any of the species at any of the 

concentrations tested.

Anesthetized fish retained their dark 

coloration, while the control fish became very 

light in response to the light background of the 

test container. This failure to change color is 

probably the result of the anesthetic upon the 

central nervous system.

Recovery began with a shivering movement that gradually increased in intensity until 

the fish had recovered fully. Lake trout gasped 

at the surface during recovery.

Generally, the anesthetization rates at the 

higher temperatures were only slightly greater 

than those in the lower temperatures. Recovery rates were notably higher in warmer 

water, presumably because of the increased 

rate of metabolism. The recovery rates in 

both temperature ranges were well within 

acceptable limits for all concentrations tested.

Muench (1958) reported that fish exposed 

to effective concentrations of quinaldine for as 

long as 2 and 3 days recovered within a few 

minutes when transferred to fresh water. He 

also stated that green sunfish held for 11 hours 

in a concentration three times greater than 

that necessary for anesthesia suffered no ill 

effects. In our experiments, all fish were 

marked and held for 2 weeks for observation 

of delayed mortality. None was observed.

CONCLUSIONS

Lake trout were more sensitive to anesthesia with quinaldine than were the other 

species tested. Under most conditions, a

concentration of 10 ppm is satisfactory for lake 

trout. Salmon and brook trout are more tolerant 

to quinaldine than lake trout, so a concentration 

of 15 ppm is suggested for these species.

Quinaldine at 15 ppm is 24 times cheaper 

than MS-222 at 1:12,000. In view of our excellent results and the difference in cost, this 

drug warrants wider use as a fish anesthetic.

REFERENCES

Bell, Gordon R.

1964 . A guide to the properties, characteristics, and uses of some general 

anesthetics for fish. Fisheries Research Board of Canada, Bulletin 148. 

4 p.

Bove', Frank].

(No date) MS-222 Sandoz, the anaesthetic 

and tranquilizer of choice for fish, 

frogs, and other cold-blooded organisms. 

Pamphlet of Sandoz, Pharmaceutical 

Chemicals Division, Hanover, New 

Jersey. 20 p.

Leitritz, Earl.

1962. Trout and salmon culture (hatchery 

methods). State of California, Department of Fish and Game, Fish Bulletin 

No. 107, p. 134-137.

Meister, Alfred L., and Charles F. Ritzi. 

1958. Effects of Chloretone and MS-222 on 

eastern brook trout. The Progressive 

Fish-Culturist, vol. 20, no. 3, p. 104- 

110.

Muench, Bruce.

1958. Quinaldine, a new anesthetic for fish. 

The Progressive Fish-Culturist, vol. 20, 

no. 1, p. 42-44 .

Stecher, Paul G. (Editor)

1960. The merck index of chemicals and 

drugs. Merck and Company, Inc., 

Rahway, New Jersey, 7th edition, 886 p.

U. S. GOVERNMENT PRINTING OFFICE : 1969 O - 331-092
(Reports 18 through 21 are in one cover.)

18. Toxicity of 22 Therapeutic Compounds to Six Fishes, by Wayne A. Willford. (Resource 

Publication 35.) 1967. lOp.

19. Toxicity of Bayer 73 to Fish, by Leif L. Marking and James W. Hogan. (Resource Publication 36.) 1967. 13p.

20. Toxicity of Dimethyl Sulfoxide (DMSO) to Fish, by Wayne A. Willford. (Resource Publication 37.) 1967. 8p.

21. Labc r-Saving Devices for Bioassy Laboratories, by Robert J. Hesselberg and Ralph M. 

Burress. (Resource Publication 38.) 1967. 8p.
As the Nation's principal conservation agency, the Department of the Interior has basic responsibilities for water, 

fish, wildlife, mineral, land, park, and recreational resources. Indian and Territorial affairs are other major 

concerns of America's "Department of Natural Resources."

The Department works to assure the wisest choice in 

managing all our resources so each will make its full 

contribution to a better United States now and in the future.

UNITED STATES 

DEPARTMENT OF THE INTERIOR

FISH AND WILDLIFE SERVICE

BUREAU OF SPORT FISHERIES AND WILDLIFE 

WASHINGTON. D. C. 2O24O