130
R. K. DELL
schlag, 1964), anatomical modifications of significance in relation to the
cold environment (Morris, 1966), and temperature tolerance (Somero
and DeVries, 1967).
Trernatomus bernacchi ranges around the Antarctic Continent, and
as far north as the South Shetlands and South Orkneys. The species
can live under sea ice for most of the year if not permanently.
Much of the American work was carried out under the leadership
of Dr Donald E. Wohlschlag acting as leader for the Stanford University
project on fishes from 1958 to 1965. Using portable field huts mounted
over holes cut through the ice, sampling programmes were maintained
throughout the year. Five or six species of fishes could be caught
commonly by lines or traps, and about the same number infrequently.
Trernatomus bernacchi appears to be active throughout most of the
year. Specimens collected during the winter normally had benthic
organisms present in their stomachs, indicating that feeding continued
throughout the year. Stomach contents indicated that the fish is
carnivorous and on occasion necrophagous (Wohlschlag, 1961). I n
McMurdo Sound the habitat of T . bernacchi remains at about -1.9"C
throughout the year, but Wohlschlag demonstrated that scale rings
could be used for ageing populations. Using this evidence he showed
that Antarctic fishes living in subzero temperatures were able to sustain a growth rate comparable with Arctic species living where temperatures may reach 10°C for two or three months, and where most
growth is achieved during the summer period (Wohlschlag, 1961).
Reproduction in Trematornus bernacchi has been studied by Hureau
(1964a) off Adelie Land (66"s) and by Dearborn (1965) in McMurdo
Sound (nearly 78'5). Dearborn examined 503 freshly caught specimens,
taken from depths ranging from two to 270 m. The number of welldeveloped eggs in any one individual ranged from 1 154 to 3 123. The
eggs are large and yolky, ranging from 1.9 to 3.9 mm in diameter, but
with the majority between 2.6 and 3.7 mm when fully mature. Dearborn believed that the available data indicated that T . bernacchi
breeds annually in McMurdo Sound, the eggs developing throughout
the winter, with the ova released in December and January. Hureau
(1964) studying the same species off the Adelie Coast found a similar
cycle, except that spawning took place from mid-October to midNovember.
Females appear to spawn first at about five years of age in both
localities. The eggs are apparently demersal, and off Adelie Land are
attached to algae. Direct evidence for demersal spawning is lacking at
McMurdo Sound, but no eggs have been obtained in very numerous
plankton tows.
R. K. DELL
schlag, 1964), anatomical modifications of significance in relation to the
cold environment (Morris, 1966), and temperature tolerance (Somero
and DeVries, 1967).
Trernatomus bernacchi ranges around the Antarctic Continent, and
as far north as the South Shetlands and South Orkneys. The species
can live under sea ice for most of the year if not permanently.
Much of the American work was carried out under the leadership
of Dr Donald E. Wohlschlag acting as leader for the Stanford University
project on fishes from 1958 to 1965. Using portable field huts mounted
over holes cut through the ice, sampling programmes were maintained
throughout the year. Five or six species of fishes could be caught
commonly by lines or traps, and about the same number infrequently.
Trernatomus bernacchi appears to be active throughout most of the
year. Specimens collected during the winter normally had benthic
organisms present in their stomachs, indicating that feeding continued
throughout the year. Stomach contents indicated that the fish is
carnivorous and on occasion necrophagous (Wohlschlag, 1961). I n
McMurdo Sound the habitat of T . bernacchi remains at about -1.9"C
throughout the year, but Wohlschlag demonstrated that scale rings
could be used for ageing populations. Using this evidence he showed
that Antarctic fishes living in subzero temperatures were able to sustain a growth rate comparable with Arctic species living where temperatures may reach 10°C for two or three months, and where most
growth is achieved during the summer period (Wohlschlag, 1961).
Reproduction in Trematornus bernacchi has been studied by Hureau
(1964a) off Adelie Land (66"s) and by Dearborn (1965) in McMurdo
Sound (nearly 78'5). Dearborn examined 503 freshly caught specimens,
taken from depths ranging from two to 270 m. The number of welldeveloped eggs in any one individual ranged from 1 154 to 3 123. The
eggs are large and yolky, ranging from 1.9 to 3.9 mm in diameter, but
with the majority between 2.6 and 3.7 mm when fully mature. Dearborn believed that the available data indicated that T . bernacchi
breeds annually in McMurdo Sound, the eggs developing throughout
the winter, with the ova released in December and January. Hureau
(1964) studying the same species off the Adelie Coast found a similar
cycle, except that spawning took place from mid-October to midNovember.
Females appear to spawn first at about five years of age in both
localities. The eggs are apparently demersal, and off Adelie Land are
attached to algae. Direct evidence for demersal spawning is lacking at
McMurdo Sound, but no eggs have been obtained in very numerous
plankton tows.