186
WILLTAM N. TAVOLGA
dition. Specialized reproductive activities, therefore, are the main interaction types among fishes that fall into the category of communication
as defined here.
Many of the sounds described and cataloged by Fish (1954, 1964)
and her co-workers were elicited from captive animals under various
unspecified conditions of duress, including administration of electric
shock. It is not known what behavioral significance these sounds could
have. Moreover, the electric shock method may in some cases produce
a neuromuscular response rather than a true behavior. Any animal with
a swim bladder is potentially capable of sound production if the body
wall muscles are abruptly stimulated to contract. Interpretations of biological significance, therefore, can only be made on the basis of field
recordings or of relatively unrestrained animals under experimental
conditions.
Some stridulatory sounds, such as those of grunts (Pomadasyidae)
and other forms that grind their pharyngeal teeth, have been recorded
only in air or from specimens grasped under water in an aquarium
( Burkenroad, 1930). The fin ray stridulations of marine catfish are produced when the animal is captured and pulled out of water (Tavolga,
1960). Such sounds are very unlikely to have any biological significance.
Many of these stridulatory sounds have most of their acoustic energy at
frequencies above the hearing range of most fishes and thus should be
considered unlikely to have any behavioral significance.
The gnashing sounds of feeding should be within the hearing range
of fishes, but these sounds have not yet been shown to have any communicative value. It is quite possible that individuals hearing other fish
eating may soon learn to come for food to the source of the sound.
Hydrodynamic sounds may also play a role in the life of both a predator
and a prey species. Sharks have long been known to approach the vicinity
of a wounded fish, and D. R. Nelson and Gruber (1963) proposed that
much of this attraction is the result of low frequency acoustic stimuli.
Young lemon sharks, Negaprion brevirostris, will not only approach
but will even attack a hydrophone that is emitting pulses of broadband noise, and similar hydrodynamic sounds were found to attract
sharks (Banner, 1968). A detailed description of field studies on the
effects of sounds on free-ranging sharks shows dramatic results
(Myrberg et al., 1969), but it is not yet clear what the specifications
and parameters of an adequately attractive stimulus are. Not only
sharks but also other predatory fishes have been shown to be
attracted to the source of low frequency sound pulses, especially those
hydrodynamic disturbances associated with active predation ( Richard,
1968). Such interactions are probably on the phasic level, sirice the stimuli
WILLTAM N. TAVOLGA
dition. Specialized reproductive activities, therefore, are the main interaction types among fishes that fall into the category of communication
as defined here.
Many of the sounds described and cataloged by Fish (1954, 1964)
and her co-workers were elicited from captive animals under various
unspecified conditions of duress, including administration of electric
shock. It is not known what behavioral significance these sounds could
have. Moreover, the electric shock method may in some cases produce
a neuromuscular response rather than a true behavior. Any animal with
a swim bladder is potentially capable of sound production if the body
wall muscles are abruptly stimulated to contract. Interpretations of biological significance, therefore, can only be made on the basis of field
recordings or of relatively unrestrained animals under experimental
conditions.
Some stridulatory sounds, such as those of grunts (Pomadasyidae)
and other forms that grind their pharyngeal teeth, have been recorded
only in air or from specimens grasped under water in an aquarium
( Burkenroad, 1930). The fin ray stridulations of marine catfish are produced when the animal is captured and pulled out of water (Tavolga,
1960). Such sounds are very unlikely to have any biological significance.
Many of these stridulatory sounds have most of their acoustic energy at
frequencies above the hearing range of most fishes and thus should be
considered unlikely to have any behavioral significance.
The gnashing sounds of feeding should be within the hearing range
of fishes, but these sounds have not yet been shown to have any communicative value. It is quite possible that individuals hearing other fish
eating may soon learn to come for food to the source of the sound.
Hydrodynamic sounds may also play a role in the life of both a predator
and a prey species. Sharks have long been known to approach the vicinity
of a wounded fish, and D. R. Nelson and Gruber (1963) proposed that
much of this attraction is the result of low frequency acoustic stimuli.
Young lemon sharks, Negaprion brevirostris, will not only approach
but will even attack a hydrophone that is emitting pulses of broadband noise, and similar hydrodynamic sounds were found to attract
sharks (Banner, 1968). A detailed description of field studies on the
effects of sounds on free-ranging sharks shows dramatic results
(Myrberg et al., 1969), but it is not yet clear what the specifications
and parameters of an adequately attractive stimulus are. Not only
sharks but also other predatory fishes have been shown to be
attracted to the source of low frequency sound pulses, especially those
hydrodynamic disturbances associated with active predation ( Richard,
1968). Such interactions are probably on the phasic level, sirice the stimuli