296
J. 11. 5. BLAXTER AND F. 0. T. HOLLIDAY
aquaria was by eye; the fish attempted to take food regardless of
shape, size or colour, once they were established. However, first
texture, and then taste, were very important in selection within the
mouth. Taste seemed to be dependent on water soluble, rather than fat
soluble, substances. Anon. (1052) found in Surdimps caerulea, however,
that the olfactory sense was of great importance in detection; this
increased feeding activity after appropriate stimulation. The importance of smell was also mentioned by Cushing (1960).
Savage (1931) made a comprehensive study of the feeding habits of
North Sea herring and reviewed earlier work by Hardy and others. He
found, by also studying the plankton, that different food organisms
were in the same proportion in the herring stomachs as in the plankton.
3. Effect of light and temperature on feeding
Clupeids not only appear usually to break shoal a t night, they also
atop feeding. This was reported in general terms by Zusser (1958a) for
pelagic plankton-catching fish. Girsa (1961) reported also that visual
feeders tend to disperse and stop feeding at about 0.1 lux. Girsa (see
Section VI, U) developed the theme that light might be a signal for
feeding and cause both attraction of fish and greater activity.
I n aquaria Battle eft al. (1936) found that captive herring did not
feed in the dark but they, Johnson (1 939a) and Blaxter and Holliday
(1!158), found feeding took place in moonlight (incident light intensity
probably about 0.25 lux). Blaxter and Holliday found a threshold light
intensity for feeding (using tungsten filament light) of about 3 lux;
optimum feeding conditions appearing to be from 100 to 1,000 lux,
feeding alwaya heing bettar when t h o daylight W[LR not too bright,.
There appeared to be nomc cvidciico for II tliiirrml f'i~wlitig r h y i h ,
feeding activity being lowest from 0400-0800 hours. Williamson (1917)
also reported that captive herring fed better in dim light. Loukaahkin
and Grant (1959) found that h'ardinops caerulea would feed as well at
5 lux as a t 200 lux, but did not try feeding the sardines in Jarknees.
I n view of their sensitivity to olfactory stimulation (Anon., 1952), thia
would make an interesting experiment.
At temperatures below 4"C, captive herring ceamd to feed (,JohnHon,
1939a; Blaxter and Holliday, 1958), and Williamson (1017) alm
reported inactivity at low temperature. Howevcr, Battle p t al. (1936)
and Farrin et al. (1957) found feeding in captive herring at, H. tA:mporatiirct
of 1°C and Kamshylov and Gerasirnov (11160) w ~ n
at . fb4"C. 'I'hc:~:
findings may have been due to a longer acclimatization to the low
temperatures, or to a difference in the physiological (or psychological)
state of the fish.
J. 11. 5. BLAXTER AND F. 0. T. HOLLIDAY
aquaria was by eye; the fish attempted to take food regardless of
shape, size or colour, once they were established. However, first
texture, and then taste, were very important in selection within the
mouth. Taste seemed to be dependent on water soluble, rather than fat
soluble, substances. Anon. (1052) found in Surdimps caerulea, however,
that the olfactory sense was of great importance in detection; this
increased feeding activity after appropriate stimulation. The importance of smell was also mentioned by Cushing (1960).
Savage (1931) made a comprehensive study of the feeding habits of
North Sea herring and reviewed earlier work by Hardy and others. He
found, by also studying the plankton, that different food organisms
were in the same proportion in the herring stomachs as in the plankton.
3. Effect of light and temperature on feeding
Clupeids not only appear usually to break shoal a t night, they also
atop feeding. This was reported in general terms by Zusser (1958a) for
pelagic plankton-catching fish. Girsa (1961) reported also that visual
feeders tend to disperse and stop feeding at about 0.1 lux. Girsa (see
Section VI, U) developed the theme that light might be a signal for
feeding and cause both attraction of fish and greater activity.
I n aquaria Battle eft al. (1936) found that captive herring did not
feed in the dark but they, Johnson (1 939a) and Blaxter and Holliday
(1!158), found feeding took place in moonlight (incident light intensity
probably about 0.25 lux). Blaxter and Holliday found a threshold light
intensity for feeding (using tungsten filament light) of about 3 lux;
optimum feeding conditions appearing to be from 100 to 1,000 lux,
feeding alwaya heing bettar when t h o daylight W[LR not too bright,.
There appeared to be nomc cvidciico for II tliiirrml f'i~wlitig r h y i h ,
feeding activity being lowest from 0400-0800 hours. Williamson (1917)
also reported that captive herring fed better in dim light. Loukaahkin
and Grant (1959) found that h'ardinops caerulea would feed as well at
5 lux as a t 200 lux, but did not try feeding the sardines in Jarknees.
I n view of their sensitivity to olfactory stimulation (Anon., 1952), thia
would make an interesting experiment.
At temperatures below 4"C, captive herring ceamd to feed (,JohnHon,
1939a; Blaxter and Holliday, 1958), and Williamson (1017) alm
reported inactivity at low temperature. Howevcr, Battle p t al. (1936)
and Farrin et al. (1957) found feeding in captive herring at, H. tA:mporatiirct
of 1°C and Kamshylov and Gerasirnov (11160) w ~ n
at . fb4"C. 'I'hc:~:
findings may have been due to a longer acclimatization to the low
temperatures, or to a difference in the physiological (or psychological)
state of the fish.