7710

• UCREFRP Catalog Number: 7710
• Author: Curry, K. D. and B. Kynard
• Title: Effect of extended galvanonarcosis on behavior of rainbow trout,
• USFW Year: 1978
• Copyright Material: YES

1300

J. FISH. RES. BOARD CAN., VOL. 35. 1978

GENERAL ACTIVITY OF GROUPS OF FISH

Immediately after treatment, groups of electrically
narcotized fish were not as active as untreated fish. The
total and pooled chi-square values show that the differ-
ence in activity was still significant after 1 h (Table 2).
Fish that had been narcotized for 0.5 h started to re-
cover by the end of the l-h evaluation period. The sig-
nificant heterogeneity chi-square values for the data in
the 1-h evaluations of this treatment group indicate
that the trend of lower group activity for treated fish
was no longer uniform 1 h after treatment. Hetero-
geneity chi-square values from the 3-h test comparisons
showed that the trend of lower group activity for treated
catfish and trout was still consistent 1 h after treatment.
Catfish from both treatments recovered from the
effects of galvanonarcosis after 24 h. Trout narcotized
for 0.5 h were fully recovered 24 h after treatment but
the group activity of the 3-h treatment groups still did
not equal that of control groups. The chi-square test
results showed that the activity levels of these trout
were not equivalent to those of the control groups. The
nonsignificant heterogeneity chi-square value indicated
that the trend of lower activity in treated fish was still
consistent in this group after 24 h of recovery (Table
2). Catfish treated for 3 h were recovered within 24 h
but the significant heterogeneity chi-square value indi-
cated an uneven trend (Table 2).

PHOTONEGATIVE BEHAVIOR

Rainbow trout and channel catfish were photonega-
tive in their immediate choice of habitat and this be-
havior persisted for the 24-h period (Fig. 1). Past
studies demonstrated that yearling rainbow trout were
photonegative (McCrimmon and Kwain 1966; Ritter
and McCrimmon 1973). Galvanonarcosis treatments
did not affect this behavior in either trout or catfish
(Fig. 1). This supported the findings of Kynard and
Lonsdale (1975).

VULNERABILITY TO PREDATION

Electrically narcotized fish were more vulnerable to
predation than controls and vulnerability increased with
the duration of treatment (Table 3). More trout from
the 0.5-h exposure group were eaten than from the un-
treated group but the chi-square comparison of the
pooled data from 10 individual tests was not significant.
In five of six individual tests, more trout narcotized
for 3 h were eaten than control fish (Table 3). The
pooled chi-square values clearly indicate the increased
vulnerability of this group (Table 3). Data from pre-
dation tests on catfish were inconclusive because of a
procedural bias that was corrected in tests on trout. In
the channel catfish predation experiments, treated and
control fish were introduced to the predator tank at the
surface. Bass predators would consume catfish before
they had time to orient within the predator tank. The

TREATMENT OURATION' 0 5-h Treatmenl D Channel Catfish l
t
Observation Period o Rainbolll Troul
Immediate I-h 24-h ~
100 S
75
50 l
VI
w 25
VI
z
0
n. 0
VI
w Test Conlrol Tell Conlrol Tesl Conlrol
lr
w
>
j::
<l
l?
w
z TREATMENT DURATION 3-h Trealment
0
f-
0
'J: Observation Period
n.
~ 100 Immediale ,.... 24-h
w
u
lr 75
w
n.
50
25
0
Tesl Control Tesl Conlrol Tes' Conlrol

EXPERIMENTAL GROUP
FIG. 1. Photonegative response of treated and control fish
at three evaluation periods after galvanonarcosis for 0.5 h
and 3 h. Sample sizes the same as in group activity. Per-
centages based on a total if all fish in each group had been in
the shade at the end of each minute for the total duration
of the observation period.

I
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!
,

TABLE 3. Numbers of treated and untreated rainbow trout
remaining after exposure to predation for 0.5 h or until one
half of the total group remained.

Treatment duration

I
t

0.5 h

3h

Observed Expected

Observed Expected

t
I

Test
Control
x2
p

24
37

30.5
30.5
2.77
<0.10

16.0
16.0
6.13
< .025

t
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t
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C
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1
S
S
e
e
f

9
23

procedure was modified for tests on trout so that all
prey were released at the bottom of the predator tank..
This permitted trout time to orient within the tank.
before being subjected to predation.

Discussion

The group activity index did not reflect the observed
differences in behavior of treated and untreated trout
in the immediate evaluations of the 3-h galvanonarcosis
treatments. Four individual treatment chi-square com-
parisons showed no difference in the group activity of
treated and control fish although the groups differed
behaviorally (Table 4). This makes the rejection of the
null hypothesis based on the pooled and total values

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