THE BEHAVIObR AND PIIYSIOLOt3Y OF HERXXNO AND OTHER CLUPEIDS 277
end of the gut, where digestion takes place (criteria being transparency
of gut contents) in 2-5 hr at 5-15°C in larvae 10-12 mm long (Blaxter,
1962). Blaxter and Hempel (1961) found digestion times of 4-6 hr at
10-12°C in slightly larger larvae, but Kurata (1959) gave times of 7-8
hr at about 9°C for Clupea pallasii larvae, clearance of the gut taking
12-20 hr, depending on the original quantity of food taken. Arthur
(1956) calculated from feeding frequencies of Sardinqs caerulea larvae
caught at sea, that digestion took from 11 i u in the smallest larvae
( 1 P 5 mm) to 3 hr in those 25 mm long. This type of analysis from seacaught larvae may not be reliable due to the difficulty of recognizhg
partly digested food, and the possibility of food being lost due to
unusual stimulation.
5. Starvation and the need for food (also gee Section I I I , F )
Very little is known about the time clupeid larvae can live without
food, though clearly this is of great importance in relation to survival
in areas of poor plankton. Blaxter (1962) found that herring larvaa in
rearing experiments could survive for 2 to 9 days without feeding.
Lishev et a,!. (1961) reported a relationship between the abundance of
herring (salaka) " fry " in the Bay of Kiga and the number of food
organisms from 1955-1961, and Nikitinskaya (1968a) that the larvae of
Clupea pallasii required a food concentration in the sea of 20-60 mg/m8.
Dementeva (1958) considered that the mortality of Sea of Azov anchovy
waa not connected with food supply, due t o the plaaticity of feeding.
Murphy (1961) estimated that the food organisms of Sardinope caerulea
were spaced so that the larvae were on average not more than 3.5-5 cm
away from a food organism.
6. Adaptations in relation to food
Nikolsky et al. (1961) compared the number of pyloric caecae and
length of the alimentary tract in larval and young herring of different
length from the Atlantic and parts of the Baltic. They showed in the
oceanic form that the number of caecae was greater, but the variability
less, while the alimentary tract was longer. They related this to the
better feeding conditions in the Atlantic, in particular high variability
being an adaptation to poor conditions (this haa a1ao been reported for
egg size).
C. Qrowth of larvae
It is not proposed to discuss the growth of clupcid larvae wtimated
from material caught on larval aurveys, though mention should bo mule
of tho work by MarRhrill el al. (1037) on tho fat content and incream in
end of the gut, where digestion takes place (criteria being transparency
of gut contents) in 2-5 hr at 5-15°C in larvae 10-12 mm long (Blaxter,
1962). Blaxter and Hempel (1961) found digestion times of 4-6 hr at
10-12°C in slightly larger larvae, but Kurata (1959) gave times of 7-8
hr at about 9°C for Clupea pallasii larvae, clearance of the gut taking
12-20 hr, depending on the original quantity of food taken. Arthur
(1956) calculated from feeding frequencies of Sardinqs caerulea larvae
caught at sea, that digestion took from 11 i u in the smallest larvae
( 1 P 5 mm) to 3 hr in those 25 mm long. This type of analysis from seacaught larvae may not be reliable due to the difficulty of recognizhg
partly digested food, and the possibility of food being lost due to
unusual stimulation.
5. Starvation and the need for food (also gee Section I I I , F )
Very little is known about the time clupeid larvae can live without
food, though clearly this is of great importance in relation to survival
in areas of poor plankton. Blaxter (1962) found that herring larvaa in
rearing experiments could survive for 2 to 9 days without feeding.
Lishev et a,!. (1961) reported a relationship between the abundance of
herring (salaka) " fry " in the Bay of Kiga and the number of food
organisms from 1955-1961, and Nikitinskaya (1968a) that the larvae of
Clupea pallasii required a food concentration in the sea of 20-60 mg/m8.
Dementeva (1958) considered that the mortality of Sea of Azov anchovy
waa not connected with food supply, due t o the plaaticity of feeding.
Murphy (1961) estimated that the food organisms of Sardinope caerulea
were spaced so that the larvae were on average not more than 3.5-5 cm
away from a food organism.
6. Adaptations in relation to food
Nikolsky et al. (1961) compared the number of pyloric caecae and
length of the alimentary tract in larval and young herring of different
length from the Atlantic and parts of the Baltic. They showed in the
oceanic form that the number of caecae was greater, but the variability
less, while the alimentary tract was longer. They related this to the
better feeding conditions in the Atlantic, in particular high variability
being an adaptation to poor conditions (this haa a1ao been reported for
egg size).
C. Qrowth of larvae
It is not proposed to discuss the growth of clupcid larvae wtimated
from material caught on larval aurveys, though mention should bo mule
of tho work by MarRhrill el al. (1037) on tho fat content and incream in