342
J. H. 9. BLAXTER AND F. 0 . T. HOLLIDAY
celestial bodies. No evidence either is forthcoming, so far, of a learning
factor in migration.
S. Vertical migration
1. Occurrence and extent of vertical migration
Since the advent of the echo-sounder it has been possible to follow
the variations and extent of vertical migration in clupeids, a study
which would have little meaning in the aquarium. Runnstrram (194lb)
was one of the pioneers of research work with the echo-sounder. H e
traced some of the characteristic movements of Atlanto-Scandian
herring, showing that the shoals rose at dusk and sank in daylight,
being found then at depths of 150 m or more. This has also been well
demonstrated and photographed by Solovyev and Degtyarev (1957).
Devold (1963) and Ryzhenko (1961) found such shoals down to 400 m
in the daytime, rising to 50 m or less by night. Dragesund (1958)
watched the diurnal movement of herring shoals when a ship lay
over them for long periods. Later Devold (1961) reported that AtlantoScandian herring were being found during their migrations down to
500 m by day, tending to keep below 100 m even at night, particularly
in later years.
In the North Sea the diurnal movements, though similar, are greatly
restricted by the depth of water. Balls (1961) has described the movements in relation to depth, particularly in the southern North Sea.
Biryukov (1958) reported a migration from 140-160 m up to 10-40 m
in the northern North Sea. Okonski and Konkol (1957) showed how
herring rose towards the aurface at night in the Skagerak. Brawn
(1960b) studied the seasonal and vertical distribution of immature
herring in Pmamaquoddy Bay. Tho cxtcnt of tho upward migration
by night i i i thiR shallow watm variod from 5-20 m doponding on the
season, tho fish boing deeper in tho month8 January to April. Tester
(1943) showed diurnal vortical movements of Clupea pallmii in British
Columbia waters and Nomura (1958) in Sardinopa melanoeticla in
Japanese waters.
The general pattern of vcrtioal migration seems to be an upward
movement at night followed by a spreading out of the fish. At dawn
the fish come together and descend. Balls (1951) called the upward
movement in the shallow southern North Sea (20-60 m) a I' wine glass "
effect, the herring being spread over the bottom by day, rising together
at dusk and spreading out again in darkneas. Cases have been reportad
(see Section VI, Q) of herring shoals or aggregationn retaining their
entity at night, but this seems less common and it is not certain what
the nature is of these group of fish. It is aim clear (lmxw, 1836;
J. H. 9. BLAXTER AND F. 0 . T. HOLLIDAY
celestial bodies. No evidence either is forthcoming, so far, of a learning
factor in migration.
S. Vertical migration
1. Occurrence and extent of vertical migration
Since the advent of the echo-sounder it has been possible to follow
the variations and extent of vertical migration in clupeids, a study
which would have little meaning in the aquarium. Runnstrram (194lb)
was one of the pioneers of research work with the echo-sounder. H e
traced some of the characteristic movements of Atlanto-Scandian
herring, showing that the shoals rose at dusk and sank in daylight,
being found then at depths of 150 m or more. This has also been well
demonstrated and photographed by Solovyev and Degtyarev (1957).
Devold (1963) and Ryzhenko (1961) found such shoals down to 400 m
in the daytime, rising to 50 m or less by night. Dragesund (1958)
watched the diurnal movement of herring shoals when a ship lay
over them for long periods. Later Devold (1961) reported that AtlantoScandian herring were being found during their migrations down to
500 m by day, tending to keep below 100 m even at night, particularly
in later years.
In the North Sea the diurnal movements, though similar, are greatly
restricted by the depth of water. Balls (1961) has described the movements in relation to depth, particularly in the southern North Sea.
Biryukov (1958) reported a migration from 140-160 m up to 10-40 m
in the northern North Sea. Okonski and Konkol (1957) showed how
herring rose towards the aurface at night in the Skagerak. Brawn
(1960b) studied the seasonal and vertical distribution of immature
herring in Pmamaquoddy Bay. Tho cxtcnt of tho upward migration
by night i i i thiR shallow watm variod from 5-20 m doponding on the
season, tho fish boing deeper in tho month8 January to April. Tester
(1943) showed diurnal vortical movements of Clupea pallmii in British
Columbia waters and Nomura (1958) in Sardinopa melanoeticla in
Japanese waters.
The general pattern of vcrtioal migration seems to be an upward
movement at night followed by a spreading out of the fish. At dawn
the fish come together and descend. Balls (1951) called the upward
movement in the shallow southern North Sea (20-60 m) a I' wine glass "
effect, the herring being spread over the bottom by day, rising together
at dusk and spreading out again in darkneas. Cases have been reportad
(see Section VI, Q) of herring shoals or aggregationn retaining their
entity at night, but this seems less common and it is not certain what
the nature is of these group of fish. It is aim clear (lmxw, 1836;