Anaesthetizing Experiments of Chum Salmon Fry with
Tricaine Methanesulfonate (M. S. 222) *Ei-ichi SAKANO

For the purpose to immobilize salmon fry for marking, tricaine methanesulfonate (M. S.

222) has been used instead of ethyl carbamate (urethane) because the latter seems to havesome harmful effects.

According to Eisler and Backiel (1960),

14 species of fish wereused to be anaesthetized with the M. S. 222 in various concentration by different authors.
In general, anaesthetizing condition varies with the species, size of fish, duration ofanaesthesia, concentration and temperature of the solution.
T h e present experiment was undertaken to determine available concentration andduration of anaesthesia by this new anaesthetic for chum salmon fry (Oncorhynchus keta).
T h e latent effect for the fry which recovered from anaesthesia was not observed.

Materials and Methods
Salmon fry used were progeny of the parents which were caught at Abashiri River in

Then theDecember, 1960, and then transferred to Chitose Hatchery at eyed egg's stage.
fry were reared in rearing pond after hatched out in January, 1961.

Fork length of thefry at the time of experiments, 24 May 1961, was 34.8mm (50 fish) in average.
T h e anaesthetic was prepared in 1 litre solution (9.5OC) with 9 lots of concentrations from1 : 10,000 to 1 : 33, 300. T h e observation was made for 5 minutes after the fry wereexposed to each solution.

In the lot in which the fry were anaesthetized within 5 minutes

the fry were left for certain times in the solution and then they were removed into runningwater (9.5OC) to examine their recovery procedure. Anaesthetized fish in this paper meansa fish which sinks to the bottom of the container and lays on the side without moving
body parts except the gill cover.
normal swimming action.

Recovery was considered when the fish takes backIn each experiment fresh fry were used.

Experimental Results and Conclusion
Experiment 1

Concentration 1 :10,0001) Anaesthetizing (10 fish)~

Time duration (min.)1

Number of fish anaesthetized

i~~~

~-~~

"Contribution No. 166 from the Hokkaido Salnion Hatchery.

283
all fishNo. 16

Scientific Reports of the Hokkaido Salmon Hatchery2) Recovering
Remaining time' (min.)Number of fish used

210581091210

all fish6-

4

all fish

Progressed time2 (rnin.)
Number of fish recovered
Number of fish died

Experiment 2-

Concentralion 1 : 1 5 , 0 0 01) Anaesthetizing (34 fish)

Time duration (min.)Number of fish anaesthetized2)

4
all fish

Recovering
Remaining time (min.)1520

Number of fish used

6106ti10

Progressed time (min.)5
all fish7
all fish121---

5

all fish

25

3

15

Remaining time (min.)510

Number of fish used555all fish

7all fish--2

Number of fish recovered

5

Number of fish died

Experiment 3 Concentration 1 : 17, 5001) Anaesthetizing (21 fish)
Time duration (min.)Number of fish anaesthetized

5all fish2) Recovering

Progressed time (min.)Number of fish recovered
Number of fish died

Exfierinzent 415
5

20
6884
1

all fish344

5
all fish1015
5
7

Concentration 1 :2 0 , O U O1) Anaesthetizing (20 fish)

Time duration (min.)Number of fish anaesthetized182) Recovering
Remaining tim (min.)Progressed time (min.)554

Number of fish recovered

Number of fish used

520
5

all fish9
all fishall fish6
all fish----Number of fish died1 T h e remaining time, in minutes. means that the fry were left f o r such duration i n the solution
just after all fish were anaesthetized, and so on.
2 T h e time, in minutes, means the observation time which was made on fry removed fromthe solution and permitted to recover in running water at such time, and so on.

104

Anaesthetizing Experiments of Chum Salmon F r yExperiment 5I)

Concentration 1 :22, 500

Anaesthetizing (12 fish)
34145
all fishRemaining time (min.)102030

Number of fish used

5535
all fish5all fish

6all fish---Time duration

59

Number of fish anaesthetized

177

10

Time duratizion (min.)5710

Number of fish anaesthetized

none

385

92

17
6

Time duration (min.)Number of fish anaesthetized2)

Recovering

Progressed tirn (min.)Number of fish recovered
Number of fish died

Experiment 6

Concentration 1 :25, 000

Anaesthetizing (1'2 fish)

Experiment 7

10
all fishConcentration I : 27, 500

Anaestheting (12 fish)

Experiment 8

12all fish

Concentration 1 :30, 000

Anaesthetizing (12 fish)
Time duration (min.)Number of fish anaesthetizedExperiment 9none

20
8Concentratioiz I : 33, 300

Anaesthetizing (10 fish)

5

Time duration (min.)none

Number of fish anaesthetized

10noneIn the practical works for marking salmon fry, the time requiring t o anaesthetize thefish shall not exceed 5 minutes.

T h e concentrations of 1 : 25, 000 (Experiment 6) and1 : 27,500 (Experiment 7) of the solution appear too weak for anaesthetizing the fish ; inboth lots the anaesthesia time was prolonged for 12 minutes after the fish were exposedto the solution.

'The fish were not anaesthetized in the solution less than 1 :30,000(Experiment 8 ) in concentration after 20 minutes exposure. T h e concentrations over1 : 22, 500 (Experiment 5) appear to be applied for this purpose. With the concentrationsof 1 : 15,000 (Experiment 2) and 1 : 10,000 (Experiment I), all fish were anaesthetizedwithin 2.5 minutes in the former and in 4 minutes in the latter, producing some deadfish due to prolonged anaesthetizing.
It is not frequent that the fry anaesthetized are left as they are in the solution for morethan 10 minutes in the usual work of marking. However, considering the individual differences in the time of anaesthetizing in the same container and the time needed for marking, the concentrations of over 1 : 15,000 (Experiment 2) seem to be injurious for the105

Scientific Reports Of the HOkkaido

Eisler andBackiel(1960)

for anaesthetize chino0ksalmon

fishfor 5 minutes.

mostthe species,

state

Adequate

size of fish andSalmonHatchery

N0.

t6

that the available concentration ts t : 33, 000 (95"F)
inches long)(3.5andthe immersion

is t0 be attime

Of anaesthetic, however, varies according

concentration

toother circumstantial situations.

SO far aS the present experiment ;s concerned taking into consideration the size Of fishandwater

thetemperature,concentrationsfrom

1 : 22, 500

to 1 : 17, 500

to be

seem

mostreasonable for the purpose.

References
Eiyler, R., andT. Backie1. 1960.

methanesulfonate(M.

JOhnson, H. E., andS. 222).

J. M.

Narcotization 0f chino0k salmon
Trans. Amer.

Shelton. 1958.

Fish. SOc., 89

Markingfingerlings withtricaine(2).

chino0k salmon

fry. Prog. Fish‑Cult.,

20 (4).
Martin,N. V., andD. C. Scott. 1959.

Use

Of tncaine methane‑sulfonate(M.

S. 222)

inthe transport of live fish without water. Prog. Fish‑Cult., 2t (4).
Nelson, P. R. 1953.

Use

Of three anaesthetics On

juvenile salmon

M.

A. Smith. 1957. Various

drugsandtrout.

Prog. Fish‑Cuk., T5 (2).
Parkhurst, Z. E., andut.

aids in spawning

rainbow

tr0‑

Prog. Fish‑Cult., I9 (1).

Thompson,R. B. 1959.

Tricaine methanesulfonate(M. S. 222) ;n transportation Of cutthroat

Prog. Fish‑Cult., 2T (2).

trout.

WO0d,aS

E. M.

Urethane

1956.

asa

carcinogen.

Prog. Fish‑Cult., I8 ( 3 )・上の要Tricainemethanesulfonate(M・糸く」S 222) は魚頼， 両懐類などの麻酔剤として最近広く用いられるようにな・つた。さけ稚魚の標識に当つての麻酔剤として，従来は ethyl・a b"m ，te (urethane) が用いら十しているが． こ「のものほ繰返し
使用するときは人体に右苫であることが分つた。しかし我国ではこのM ． S． 222 を 鮎鱒稚魚の麻酔に用いた記録はないので，この薬品をさけ
稚魚の標識の際の麻酔に用いるにあたって，どれ位の濃度のものが適当かを実験した。

使用したさけは， 網走事業場で採卵 L 千歳支場に移殖したものの稚魚で， 夫験時のフ オークレリグスは34 ． 8住。 また安強時の水温は9． 5 。 C であつた。液の濃度はl : l0,000 から l :33,300までの9 種頼とし，稚魚がこの中で5 分以内に麻酔L ， 更に麻酔汲の中に多少の時間放置しても擁死魚を上ずることのないところの濃度を求・めた。

夫験の結果は (1) 1 : 25,000u"

ドの 濃度では淡すぎて，麻酔の目的には用いられない， (2) 立た l : l5,000 以

濃庄では麻酔波の中に放間 される時問によつては弊死魚を生ずることがある。 L3 げ）

場令もつとも適当な濃度である。
から l :22 ， 500 の範囲がこの106

き よ {