16 
PACIFIC SCIENCE, Vol. XXII, January 1968 
TABLE 2 
Durations of the First Five Sounds Produced by Normal and Operated Triggerfishes 
SOUND 
DURATION 
(msec) 
SPECIES 
CONDITION 
X 
S. D. 
T-VALUE 
PROBABILITY 
Rhinecanthus rectangulus 
normal 
one spine removed 
normal 
rays unilaterally removed 
180 
128 
179 
149 
84 
69 
53 
46 
6.6667 
7.1154 
0.005 
0.005 
Melichthys piceus 
normal 
one spine removed 
normal 
rays unilaterally removed 
212 
175 
185 
170 
92 
79 
76 
62 
1.5473 
0.7716 
0.1 
0.2 
Batistes vetula 
normal 
one spine removed 
99 
93 
19 
21 
0.6867 
0.5 
normal 
rays unilaterally removed 
92 
100 
18 
20 
1.5472 
0.1 
leave the area and continue swimming until 
another hole was found. Eventually, each fish 
entered a hole and extended its dorsal and 
ventral spines against the walls of the space. 
When attempts were made to grasp the fish 
and pull it from the area, a rapid burst of sound 
was produced. The sounds could sometimes be 
elicited by directing water currents into the area. 
No sounds were heard until currents were pro- 
duced or until grasping attempts were made. 
TABLE 3 
Relative Distribution of Sound Pressure Within Octave Bands (Hz) in Sound Produced 
by Triggerfishes 1 
SOUND PRESSURE (db) 
IN OCTAVE 
BANDS 2 
75- 
150- 
300- 
600- 
1200- 
2400- 
4800- 
9600- 
SPECIES 
150 
300 
600 
1200 
2400 
4800 
9600 
19200 
Melichthys 
—20.6 
— 13.8 
—8.2 
— 5.8 
— 8.2 
— 16.1 
— 31.8 
— 
buniva 
7-21 
3-18 
4-11 
1-10 
4-12 
9-21 
26-37 
— 
Melichthys 
-8.3 
-4.4 
—6.8 
-9.9 
— 11.7 
— 18.6 
-23.6 
— 
vidua 
4-11 
1-6 
2-12 
3-14 
7-23 
10-27 
13-38 
— 
Melichthys 
— 12.3 
-4.9 
-4.1 
—8.7 
-13.7 
—20.5 
-29.9 
— 
piceus 
9-17 
2-11 
2-7 
6-13 
10-18 
17-25 
27-35 
— 
Batistes 
— 16.8 
-9.7 
-6.4 
—8.0 
— 5.1 
— 10.1 
— 22.1 
—24.1 
bursa 
11-27 
4-18 
3-10 
2-11 
2-17 
2-21 
15-31 
22-40 
Batistes 
—8.4 
— 3.8 
—4.5 
—8.9 
— 11.7 
— 18.0 
-25.4 
— 
capistratus 
5-14 
2-7 
2-10 
2-14 
2-18 
10-28 
11-33 
— 
Batistes 
-16.3 
— 10.1 
-5.9 
-3.0 
—8.5 
— 12.8 
—24.1 
— 
vetula 
11-21 
2-14 
3-10 
1-8 
6-11 
9-19 
15-30 
— 
Rhinecanthus 
—4.8 
—4.8 
— 5.1 
— 11.2 
— 15.6 
—23.0 
-26.3 
— 
rectangulus 
3-8 
1-8 
3-10 
8-16 
2-17 
13-31 
24-34 
— 
1 Data show mean and range of pressures at each octave band. 
2 Numbers represent db below total sound energy, so that smallest reductions represent octave bands of greatest amplitude. 
