REVIEW OF THE SYSTEMATICS AND ECOLOGY OF OCEAMC SQUIDS
155
that young stages occur nearer the surface in high latitudes although,
in the Norwegian Sea, larvae were found at a mean depth of 300 m
and rarely at 0-50 m (Nesis, 1965). There is some evidence that smaller
juveniles live nearer the surface (Nesis, 1965). Off Oregon, Pearcy
(1965) found that an average of 0.5 squids per hour were caught in
open midwater trawls fished at 200 m and 600 m, while only 0.1 per
hour were caught in an open trawl fished a t 1000 m. He aIso found
evidence that young squid moved down in daytime and up into the
upper 200 m at night. Adults have been taken with open nets fished
to 100 m and to as much as 4 000 m and have been recovered inshore
(Bruun, 1946) although their usual habitat is probably at 100 to 1000 m
over deep water. Hoyle (1886a) records an adult which " flew " on
board a vessel. While Muus (1962) believed that there wae a short
spawning period in the Greenland region; Nesis (1965) found evidence
for spawning from mid-April to December with a peak period in late
May and June. By combining the data of Muus (1962) and Nesis
(1965) it appears that the very young juveniles of less than 1.0 cm
mantle length present in May and June grow to 14-3-0 cm by July
and 2-0-4.0 cm by August and September. In September there are also
animals of 8.0-20-0 cm in mantle length which were presumably
spawned the previous year. From his rather sparse data Muus concluded that there is probably a 2-year development period and a large
specimen of 24.0 cm was thought to be possibly 3 years old. What
figures are given, however, do not exclude a 1-year development.
In the Norwegian Sea the main hatching period is from late March to
June or July (Nesis, 1965). Spawning seems to take place over great
depths and the adults occupy the same geographical area as the
young and this led Nesis (1965) to conclude that there is no spawning
migration. However, in spring and summer large numbers of adults
migrate into the Norwegian Sea from the Atlantic (Grimpe, 1933;
MUUS, 1962) and it seems possible that this is related to spawning.
Off Oregon, about eight times more larvae were caught over the
continental slope in summer than in winter and Pearcy (1965) suggested
that this was due to an influx of squid into the region, a view supported
by the size distributions of the larvae. Pearcy further concluded that
hatching of Qonatus fabricii is probably not limited to a short season;
however, if migration takes place, growth as shown by distribution
curves may be obscured.
During growth, the arms and tentacles become relatively longer
and then shorter, the head becomes relatively shorter, the body becomes
narrower and the fins become relatively longer (Fig. 24). Degner (1925)
has described the development of hooks on the tentacle club. The
155
that young stages occur nearer the surface in high latitudes although,
in the Norwegian Sea, larvae were found at a mean depth of 300 m
and rarely at 0-50 m (Nesis, 1965). There is some evidence that smaller
juveniles live nearer the surface (Nesis, 1965). Off Oregon, Pearcy
(1965) found that an average of 0.5 squids per hour were caught in
open midwater trawls fished at 200 m and 600 m, while only 0.1 per
hour were caught in an open trawl fished a t 1000 m. He aIso found
evidence that young squid moved down in daytime and up into the
upper 200 m at night. Adults have been taken with open nets fished
to 100 m and to as much as 4 000 m and have been recovered inshore
(Bruun, 1946) although their usual habitat is probably at 100 to 1000 m
over deep water. Hoyle (1886a) records an adult which " flew " on
board a vessel. While Muus (1962) believed that there wae a short
spawning period in the Greenland region; Nesis (1965) found evidence
for spawning from mid-April to December with a peak period in late
May and June. By combining the data of Muus (1962) and Nesis
(1965) it appears that the very young juveniles of less than 1.0 cm
mantle length present in May and June grow to 14-3-0 cm by July
and 2-0-4.0 cm by August and September. In September there are also
animals of 8.0-20-0 cm in mantle length which were presumably
spawned the previous year. From his rather sparse data Muus concluded that there is probably a 2-year development period and a large
specimen of 24.0 cm was thought to be possibly 3 years old. What
figures are given, however, do not exclude a 1-year development.
In the Norwegian Sea the main hatching period is from late March to
June or July (Nesis, 1965). Spawning seems to take place over great
depths and the adults occupy the same geographical area as the
young and this led Nesis (1965) to conclude that there is no spawning
migration. However, in spring and summer large numbers of adults
migrate into the Norwegian Sea from the Atlantic (Grimpe, 1933;
MUUS, 1962) and it seems possible that this is related to spawning.
Off Oregon, about eight times more larvae were caught over the
continental slope in summer than in winter and Pearcy (1965) suggested
that this was due to an influx of squid into the region, a view supported
by the size distributions of the larvae. Pearcy further concluded that
hatching of Qonatus fabricii is probably not limited to a short season;
however, if migration takes place, growth as shown by distribution
curves may be obscured.
During growth, the arms and tentacles become relatively longer
and then shorter, the head becomes relatively shorter, the body becomes
narrower and the fins become relatively longer (Fig. 24). Degner (1925)
has described the development of hooks on the tentacle club. The