188
WILLIAM N. TAVOLGA
that many of the instances of sounds used in reproductive behavior represent signal level communication, but needed data on specificity of the
signal are often lacking.
Although no sex differences appear to exist in the morphology of the
sonic mechanisms of the Batrachoididae, only male toadfish, Opsanus tau,
are known to emit boat-whistle sounds (Gray and Winn, 1981; Winn,
1964), and only males of the midshipman, Porichthys notatus, produce
any sounds at all ( Cohen and Winn, 1967).
Some species appear to produce sounds when schooling or aggregating. Aggregations of sea robins produce a characteristic staccato call
(Moulton, 1956), and nighttime schools of marine catfish form large
choruses ( Tavolga, 1960).
In some long-term observations of local populations, Breder (1968)
found that the sea catfish, Galeichthys felis, aggregate and produce
choruses of the “percolator” sounds from April to October, with a lull in
July and August. These choruses usually start after 5 P.M. and cease before
11 P.M. Optimum water temperatures for chorus formation were from
74” to 89°F) and increased chorusing was noted during new moon
periods.
Breder (1968) also observed that the boat-whistle sounds of the
toadfish, Opsanus beta, were normally heard in March, April, August,
September, and October, usually most frequently when the Gabichthys
choruses were most vigorous. The repetition rate of the toadfish calls was
found to be temperature dependent, averaging 0.93lmin at 74°F and
1.92lmin at 83°F. Toadfish calls of this Florida west coast species disappeared at water temperatures below 73°F and above 91°F.
As in the catfish (above), many species seem to show a daily rhythm
in their sonic behavior. Winn et al. (1964) demonstrated this cyclic
activity in the squirrelfish. This species, as well as many others, tend to
show dawn and dusk peaks of sonic activity, possibly correlated with
feeding or territorial movements. Cummings et al. (1964) found a cyclic
occurrence, with dawn and dusk peaks, for many sounds of biological
origin as monitored by a shore-based hydrophone system.
Since so many of the sounds produced by different species are similar,
Winn (1964) proposed that the coding of information may be through
temporal patterning. With the exception of a few species, like the toadfish, that produce harmonic tones, most fish sounds are short pulses with
a fundamental near 100 Hz. There are, however, distinct differences
among species in the grouping and repetition rates of these pulses, It
is conceivable, according to Winn, that species discrimination and the
communication of information as to emotional state ( i.e., alarm, territorial
WILLIAM N. TAVOLGA
that many of the instances of sounds used in reproductive behavior represent signal level communication, but needed data on specificity of the
signal are often lacking.
Although no sex differences appear to exist in the morphology of the
sonic mechanisms of the Batrachoididae, only male toadfish, Opsanus tau,
are known to emit boat-whistle sounds (Gray and Winn, 1981; Winn,
1964), and only males of the midshipman, Porichthys notatus, produce
any sounds at all ( Cohen and Winn, 1967).
Some species appear to produce sounds when schooling or aggregating. Aggregations of sea robins produce a characteristic staccato call
(Moulton, 1956), and nighttime schools of marine catfish form large
choruses ( Tavolga, 1960).
In some long-term observations of local populations, Breder (1968)
found that the sea catfish, Galeichthys felis, aggregate and produce
choruses of the “percolator” sounds from April to October, with a lull in
July and August. These choruses usually start after 5 P.M. and cease before
11 P.M. Optimum water temperatures for chorus formation were from
74” to 89°F) and increased chorusing was noted during new moon
periods.
Breder (1968) also observed that the boat-whistle sounds of the
toadfish, Opsanus beta, were normally heard in March, April, August,
September, and October, usually most frequently when the Gabichthys
choruses were most vigorous. The repetition rate of the toadfish calls was
found to be temperature dependent, averaging 0.93lmin at 74°F and
1.92lmin at 83°F. Toadfish calls of this Florida west coast species disappeared at water temperatures below 73°F and above 91°F.
As in the catfish (above), many species seem to show a daily rhythm
in their sonic behavior. Winn et al. (1964) demonstrated this cyclic
activity in the squirrelfish. This species, as well as many others, tend to
show dawn and dusk peaks of sonic activity, possibly correlated with
feeding or territorial movements. Cummings et al. (1964) found a cyclic
occurrence, with dawn and dusk peaks, for many sounds of biological
origin as monitored by a shore-based hydrophone system.
Since so many of the sounds produced by different species are similar,
Winn (1964) proposed that the coding of information may be through
temporal patterning. With the exception of a few species, like the toadfish, that produce harmonic tones, most fish sounds are short pulses with
a fundamental near 100 Hz. There are, however, distinct differences
among species in the grouping and repetition rates of these pulses, It
is conceivable, according to Winn, that species discrimination and the
communication of information as to emotional state ( i.e., alarm, territorial