at upper frequencies that transmit over greater distances (see Fine and
Lenhardt 1983).
In summary, the adoption of a sonic swim bladder mechanism favors both
the production of low-frequency signals for short-distance communication
and stereotyped signals that will enhance detection and recognition by
potential mates or nest intruders.
13.3. Ecological–Structural Mechanisms
Kalmijn (1988, 1989) proposes that near-field detection is the original function of the inner ear of fishes, a function that has been maintained among
extant species. Thus, although the lateral line functions in the detection of
local hydrodynamic flow in the very near field (see Coombs and Janssen
1988), the inner ear functions for detecting the remaining part of the near
field. This would explain, in part, the historical origins and current maintenance of the low-frequency range for fish hearing.
The inner ear of teleost fishes includes otolithic end organs that function
in hearing and are sensitive to particle motions that are prominent in the
near field (Popper and Fay 1993).Although several distantly related teleosts
possess structural adaptations that enhance the detection of the propagating sound wave and are considered “hearing specialists,” most species lack
these specializations and are classified as “hearing generalists” or “nonspecialists.” The absence of accessory organs does not eliminate either
detection of the propagating sound wave or a hearing sensitivity comparable to that of specialists in the relevant frequency range (see discussion
in McKibben and Bass 1999).
Given that the range of particle motion in the near field (an abiotic ecological variable) should increase as a sound’s wavelength increases (Section
3.3), low-frequency sounds should extend the detection range of the
teleostean inner ear (structural character).
14. Summary Comments
We reviewed some of the basic principles underlying sound transmission in
any medium and more specifically addressed the physical attributes of
aquatic environments that could influence transmission and hence acoustic
communication in underwater environments. We considered the influence
of physical acoustics on sound production in two divergent vertebrate
groups, cetaceans and teleost fishes, that are found in either deep
(cetaceans) or coastal/very shallow (cetaceans and teleost fishes) water
habitats.
The available evidence suggests that cetacean vocalizations are wellmatched to the general transmission properties of their environments. Thus,
a behavioral–ecological explanation for the physical attributes of cetacean
2. Physical Acoustics of Underwater Sound Communication
57
Lenhardt 1983).
In summary, the adoption of a sonic swim bladder mechanism favors both
the production of low-frequency signals for short-distance communication
and stereotyped signals that will enhance detection and recognition by
potential mates or nest intruders.
13.3. Ecological–Structural Mechanisms
Kalmijn (1988, 1989) proposes that near-field detection is the original function of the inner ear of fishes, a function that has been maintained among
extant species. Thus, although the lateral line functions in the detection of
local hydrodynamic flow in the very near field (see Coombs and Janssen
1988), the inner ear functions for detecting the remaining part of the near
field. This would explain, in part, the historical origins and current maintenance of the low-frequency range for fish hearing.
The inner ear of teleost fishes includes otolithic end organs that function
in hearing and are sensitive to particle motions that are prominent in the
near field (Popper and Fay 1993).Although several distantly related teleosts
possess structural adaptations that enhance the detection of the propagating sound wave and are considered “hearing specialists,” most species lack
these specializations and are classified as “hearing generalists” or “nonspecialists.” The absence of accessory organs does not eliminate either
detection of the propagating sound wave or a hearing sensitivity comparable to that of specialists in the relevant frequency range (see discussion
in McKibben and Bass 1999).
Given that the range of particle motion in the near field (an abiotic ecological variable) should increase as a sound’s wavelength increases (Section
3.3), low-frequency sounds should extend the detection range of the
teleostean inner ear (structural character).
14. Summary Comments
We reviewed some of the basic principles underlying sound transmission in
any medium and more specifically addressed the physical attributes of
aquatic environments that could influence transmission and hence acoustic
communication in underwater environments. We considered the influence
of physical acoustics on sound production in two divergent vertebrate
groups, cetaceans and teleost fishes, that are found in either deep
(cetaceans) or coastal/very shallow (cetaceans and teleost fishes) water
habitats.
The available evidence suggests that cetacean vocalizations are wellmatched to the general transmission properties of their environments. Thus,
a behavioral–ecological explanation for the physical attributes of cetacean
2. Physical Acoustics of Underwater Sound Communication
57