6. SOUND PRODUCTION AND DETECTION
183
IV. ACOUSTIC COMMUNICATION IN FISH
The channels available for animal interactions are: photic (visual),
mechanical ( including tactual and acoustical), thermal, chemical
(gustatory and olfactory), and electrical (limited to certain fishes).
Information transmitted along any of these channels can be broadly
classified as: long range vs. short range and directional vs. nondirectional.
Each of these channels has certain limitations in an aquatic medium as
compared with a terrestrial environment.
The photic channel is severely limited in water (Dietrich, 1963),
especially in seawater in regions of high planktonic concentration. The
probability is that the range for effective vision in the marine environment
is generally less than 1 meter, and in areas of high turbidity this effective
range may be reduced to only a few centimeters.
The chemical channel is potentially an effective one in water, because
of the large range of substances that are easily suspended or dissolved in
water. This channel, however, is slow and nondirectional, and the source
of the stimulus can be located only by means of some kinesislike movements in which the animal simply moves about until it finds areas of
progressively higher stimulus concentrations.
Although useful in a terrestrial environment, the thermal channel is
virtually unavailable to aquatic animals, especially to ectothermic forms
such as fishes. Water absorbs heat rapidly, and a thermal gradient attenuates much too fast for any effective reception as a stimulus in an
interaction.
Both ac and dc electrical fields are readily set up in water, especially
in saltwater, and many species of fishes, in addition to the well-known
electrical forms, are now known to be able to detect electrical potentials
produced by other organisms. How widely this energy channel is used
in interaction among fishes still remains to be studied.
Aside from the short-range, direct contact function of tactile receptors,
the mechanical channel offers several advantages for interactions and
communication among fishes. Acoustic energy under water is effective
as pressure and as displacement. Both the inner ear and the lateral line
are essentially displacement sensitive, but the inner ear receives nearfield displacements from the nearby swim bladder. The swim bladder
acts as a transducer for pressure waves and transforms them into local
near-field effects (Harris and van Bergeijk, 1962; van Bergeijk, 1964). Pure
pressure waves are efficiently propagated in water and this form of
acoustic energy is probably the most rapid and effective channel for
long-range interactions. At short range, directional orientation to a sound
183
IV. ACOUSTIC COMMUNICATION IN FISH
The channels available for animal interactions are: photic (visual),
mechanical ( including tactual and acoustical), thermal, chemical
(gustatory and olfactory), and electrical (limited to certain fishes).
Information transmitted along any of these channels can be broadly
classified as: long range vs. short range and directional vs. nondirectional.
Each of these channels has certain limitations in an aquatic medium as
compared with a terrestrial environment.
The photic channel is severely limited in water (Dietrich, 1963),
especially in seawater in regions of high planktonic concentration. The
probability is that the range for effective vision in the marine environment
is generally less than 1 meter, and in areas of high turbidity this effective
range may be reduced to only a few centimeters.
The chemical channel is potentially an effective one in water, because
of the large range of substances that are easily suspended or dissolved in
water. This channel, however, is slow and nondirectional, and the source
of the stimulus can be located only by means of some kinesislike movements in which the animal simply moves about until it finds areas of
progressively higher stimulus concentrations.
Although useful in a terrestrial environment, the thermal channel is
virtually unavailable to aquatic animals, especially to ectothermic forms
such as fishes. Water absorbs heat rapidly, and a thermal gradient attenuates much too fast for any effective reception as a stimulus in an
interaction.
Both ac and dc electrical fields are readily set up in water, especially
in saltwater, and many species of fishes, in addition to the well-known
electrical forms, are now known to be able to detect electrical potentials
produced by other organisms. How widely this energy channel is used
in interaction among fishes still remains to be studied.
Aside from the short-range, direct contact function of tactile receptors,
the mechanical channel offers several advantages for interactions and
communication among fishes. Acoustic energy under water is effective
as pressure and as displacement. Both the inner ear and the lateral line
are essentially displacement sensitive, but the inner ear receives nearfield displacements from the nearby swim bladder. The swim bladder
acts as a transducer for pressure waves and transforms them into local
near-field effects (Harris and van Bergeijk, 1962; van Bergeijk, 1964). Pure
pressure waves are efficiently propagated in water and this form of
acoustic energy is probably the most rapid and effective channel for
long-range interactions. At short range, directional orientation to a sound