456
MALCOLM S. CORDON
Kulikov (1964) has made some observations on the effects of sudden
decompressions on Bering Sea sablefish, Anoplopoma fimbria. These fish
generally live at considerable depths but can perform long vertical
migrations. Substantial sudden decompressions (magnitude unspecified)
had no adverse effects.
A group of Russian workers has made a series of metabolic studies
on various Siberian freshwater fishes subjected for periods of a few
hours to pressures of 25 atm (Lopukhova, 1964; Pegel' et al., 1964,
1966). Unavailability of the original papers makes the following summary
entirely dependent upon English translations of the authors' abstracts.
Experiments were carried out with ide, dace, gudgeon, crucian carp,
and perch. Measurements made included oxygen consumption, carbon
dioxide excretion, oxygen content of blood hemoglobin, blood sugar
level, electrocardiogram, and conditioned reflex responses. There is no
indication that the oxygen consumption and carbon dioxide excretion
rate measurements took into account possible changes in activity levels
of the fishes. Experimental temperatures varied seasonally from 9" to
11°C in winter to 18°C in summer.
The overall conclusion was that during spring-summer periods of increased activity increased pressures stimulated the fishes' physiological
processes. During fall-winter periods of reduced activity increased
pressures inhibited these same processes. There were variations in detail
between species, but results were broadly as follows.
Pressure increases of 24 atm in spring and summer produced increases of 20% in oxygen consumption, increased blood levels of oxyhemoglobin, decreased blood sugar levels, and no change in conditioned
reflex responses. Similar pressure increases in fall and winter produced
a 20% decrease in oxygen uptake, 60440% increase in carbon dioxide excretion, higher blood sugar levels, lower blood oxyhemoglobin levels,
lowered R waves in the electrocardiograms (interpreted as decreased
conductivity of heart muscle), and increased lag times for conditioned
reflexes. The reflexes apparently eventually disappeared altogether. The
experiments with dace were apparently particularly variable and sometimes inconsistent ( Pegel' et al., 1964). The abstract of the most recent
summary of the work (Pegel' et al., 1966) is in several ways inconsistent
with the abstract of what appears to be the major experimental paper
( Lopukhova, 1964).
C. High Pressures
Work on the effects on fishes of high pressures (above 5 atm) has
been a bit more diversified than the work at low pressures. Some con-
MALCOLM S. CORDON
Kulikov (1964) has made some observations on the effects of sudden
decompressions on Bering Sea sablefish, Anoplopoma fimbria. These fish
generally live at considerable depths but can perform long vertical
migrations. Substantial sudden decompressions (magnitude unspecified)
had no adverse effects.
A group of Russian workers has made a series of metabolic studies
on various Siberian freshwater fishes subjected for periods of a few
hours to pressures of 25 atm (Lopukhova, 1964; Pegel' et al., 1964,
1966). Unavailability of the original papers makes the following summary
entirely dependent upon English translations of the authors' abstracts.
Experiments were carried out with ide, dace, gudgeon, crucian carp,
and perch. Measurements made included oxygen consumption, carbon
dioxide excretion, oxygen content of blood hemoglobin, blood sugar
level, electrocardiogram, and conditioned reflex responses. There is no
indication that the oxygen consumption and carbon dioxide excretion
rate measurements took into account possible changes in activity levels
of the fishes. Experimental temperatures varied seasonally from 9" to
11°C in winter to 18°C in summer.
The overall conclusion was that during spring-summer periods of increased activity increased pressures stimulated the fishes' physiological
processes. During fall-winter periods of reduced activity increased
pressures inhibited these same processes. There were variations in detail
between species, but results were broadly as follows.
Pressure increases of 24 atm in spring and summer produced increases of 20% in oxygen consumption, increased blood levels of oxyhemoglobin, decreased blood sugar levels, and no change in conditioned
reflex responses. Similar pressure increases in fall and winter produced
a 20% decrease in oxygen uptake, 60440% increase in carbon dioxide excretion, higher blood sugar levels, lower blood oxyhemoglobin levels,
lowered R waves in the electrocardiograms (interpreted as decreased
conductivity of heart muscle), and increased lag times for conditioned
reflexes. The reflexes apparently eventually disappeared altogether. The
experiments with dace were apparently particularly variable and sometimes inconsistent ( Pegel' et al., 1964). The abstract of the most recent
summary of the work (Pegel' et al., 1966) is in several ways inconsistent
with the abstract of what appears to be the major experimental paper
( Lopukhova, 1964).
C. High Pressures
Work on the effects on fishes of high pressures (above 5 atm) has
been a bit more diversified than the work at low pressures. Some con-