THE BEHAVIOUR AND PHYSIOLOGY OF HERRING AND OTHER CLUPEIDS 313
aquarium diet, could affect the temperature tolerance. Using young
Passamaquoddy herring she found that unacclimatized fish would
withstand -1°C for a short time. There was a 50% mortality of
unacclimatized herring 11.1-21-9 cm long at temperatures of 21.219.5"C in 48 hr, the smaller fish being more tolerant. As mentioned in
the section on osmo-regulation, the freezing point of herring blood is
about 4 - 9 5 " C ; temperatures below this would quickly freeze the blood
unless super-cooling or depression of the freezing point took place.
Suehiro (1951), observing the factors causing mortality in bait &shes,
found that unacclimatized Sardinops melanosticta 114-15-1 cm long
had an approximate temperature range of 7-29°C ; Engraulis japonicw
5.6-13.7 cm long had a range of ll-31°C. Phillips and Radovich (1952)
thought that Sardinops caerulea had an upper level of tolerance of about
26°C. Graham (1956) acclimatized Pornolobus psezcdoharengus to 5, 10,
15 and 20"C, and found the adults had an upper lethal limit (until 50%
died on continual exposure) of 20-23°C (acclimatized at 10-20°C) and
the yearlings of 15-23°C (acclimatized 5-9°C).
As reported in Section VI, B, low temperatures cause a reduction in
both general and feeding activity, the temperature at which feeding
ceases depending on the time of acclimatization.
2. Oxygen
Kamshylov and Gerasimov (1960) found that young Murman
herring (? 10 cm) died at oxygen values below 2 ml/litre (30-33"/,
saturation). Suehiro (1951) measured the oxygen requirements of
clupeids. He reported that Sardinops melanosticta and Engraulis
japonicw showed sigria of difficulty at about 3 rnl/litro, ttic mtr! of
respiration increased and t h y put thcir W)H(:H Ht)ovt: t,tm wtitm. ' I ' h
average lethal oxygen concentration for ,Yurdimp wau 2-02 ml/lit,rc
and for Engraulis 1.82 ml/litre.
3. CO, and H,S
Shelford and Powers (1915) used young Clupea p a k i i 6 cm long,
and found that they died in 6 min whcn t h c H,S conrx-mtration W ~ L H
7.6 ml/litre and in 159 min when the CO, concc:ntration wa8 20 ml/IJt,rc,.
J. Thebrain
The physiology of the nervous system is virtually unknown in
clupeids. Lissner (1925) and Blaxter and Holliday (1968) described
the brain in relation to feeding (see Fig. 9), following the similar study
of Evans (1952) on cyprinid fishes. The optic lobes in the herring
dominate the fore-brain, indicating the importance of sight ; the large
aquarium diet, could affect the temperature tolerance. Using young
Passamaquoddy herring she found that unacclimatized fish would
withstand -1°C for a short time. There was a 50% mortality of
unacclimatized herring 11.1-21-9 cm long at temperatures of 21.219.5"C in 48 hr, the smaller fish being more tolerant. As mentioned in
the section on osmo-regulation, the freezing point of herring blood is
about 4 - 9 5 " C ; temperatures below this would quickly freeze the blood
unless super-cooling or depression of the freezing point took place.
Suehiro (1951), observing the factors causing mortality in bait &shes,
found that unacclimatized Sardinops melanosticta 114-15-1 cm long
had an approximate temperature range of 7-29°C ; Engraulis japonicw
5.6-13.7 cm long had a range of ll-31°C. Phillips and Radovich (1952)
thought that Sardinops caerulea had an upper level of tolerance of about
26°C. Graham (1956) acclimatized Pornolobus psezcdoharengus to 5, 10,
15 and 20"C, and found the adults had an upper lethal limit (until 50%
died on continual exposure) of 20-23°C (acclimatized at 10-20°C) and
the yearlings of 15-23°C (acclimatized 5-9°C).
As reported in Section VI, B, low temperatures cause a reduction in
both general and feeding activity, the temperature at which feeding
ceases depending on the time of acclimatization.
2. Oxygen
Kamshylov and Gerasimov (1960) found that young Murman
herring (? 10 cm) died at oxygen values below 2 ml/litre (30-33"/,
saturation). Suehiro (1951) measured the oxygen requirements of
clupeids. He reported that Sardinops melanosticta and Engraulis
japonicw showed sigria of difficulty at about 3 rnl/litro, ttic mtr! of
respiration increased and t h y put thcir W)H(:H Ht)ovt: t,tm wtitm. ' I ' h
average lethal oxygen concentration for ,Yurdimp wau 2-02 ml/lit,rc
and for Engraulis 1.82 ml/litre.
3. CO, and H,S
Shelford and Powers (1915) used young Clupea p a k i i 6 cm long,
and found that they died in 6 min whcn t h c H,S conrx-mtration W ~ L H
7.6 ml/litre and in 159 min when the CO, concc:ntration wa8 20 ml/IJt,rc,.
J. Thebrain
The physiology of the nervous system is virtually unknown in
clupeids. Lissner (1925) and Blaxter and Holliday (1968) described
the brain in relation to feeding (see Fig. 9), following the similar study
of Evans (1952) on cyprinid fishes. The optic lobes in the herring
dominate the fore-brain, indicating the importance of sight ; the large