AIR BREATHING IN FISHES*
W E L L JOHANSEN
I. Occurrence and Bionomics of Air-Breathing Fishes
.
11. Nature of the Structural Adaptations for Air Breathing
A. Structural Derivatives of the Mouth and Pharynx as
Air-Breathing Organs . . . . . . .
B. Structural Adaptations of the Gastrointestinal Tract
for Air Breathing . . . . . . . .
C. The Air Bladder as a Respiratory Organ
. . .
111. Physiological Adaptations in Air-Breathing Fishes . .
A. Respiratory Properties of Blood . . . . .
B. Gas Exchange in Air-Breathing Fishes
. . .
C. Internal Gas Transport in Air-Breathing Fishes
.
D. Control of Breathing in Air-Breathing Fishes
. .
E. Normal Breathing Behavior . . . . . .
F. Breathing Responses to Changes in External
Gas Composition
. . . . . . . .
G. Breathing Responses to Mechanical Stimuli
. .
H. Breathing Response to Air Exposure . . . .
I. Coupling of Respiratory and Circulatory Events
.
References
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I. OCCURRENCE AND BIONOMICS OF
AIR-BREATHING FISHES
Natural selection of air-breathing habits in fishes has occurred many
times and in diverse ways during vertebrate evolution.
The majority of extant fishes showing structural adaptations for direct
use of atmospheric oxygen are tropical freshwater or estuarine forms.
Most air-breathing fishes are teleosts but typically the dipnoan, chon* This chapter was written while the author was supported by grants GB 7166
from the National Science Foundation and HE 12071 from the National Institutes of
Health.
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