276
J. H. 9. BLAXTER AND F. 0. T. H O U I D A Y
speoies seemed to feed only by day, indicating the importance of
vision.
3. Type and quantity of food taken
Bowers and Williamson (1951) and Bhattacharyya (1957) have
reviewed the large amount of work done on feeding of herring larvae
caught at sea from the analysis of gut contents. While it is not intended to discuss the results in detail, it may be said that the size of
food organisms taken seems to increase with the size of larvae and a
limited selection (or rejection) takes place. For example, organisms
such as the copepod Acartia, the diatom Biddulphia and dinoflagellate Ceratium, though present in the plankton, are not found in the gut.
As larvae grow older they tend to take larger food organisms.* The
apparently low percentage of larvae feeding reported by some authors,
though not for the larger larvae examined by Bowers and Williamson,
may be due to rapid digestion or defaecation on capture or fixation, or
to night sampling. Arthur (1986) suggested that mainly sickly or
starving Sardinqps caerulea larvae might be caught, giving a biased
estimate of percentage feeding. He also gave details of the feeding of
these larvae and showed how the size of food increased from up to Sop
when 4mm long to 200p when 10 mm long. Cushing (1960) also
described the increase in size of food taken by larvae of this species
as it grew.
The importance of phytoplankton for clupeid larvae has been under
discussion for many years. For example, Hardy (1924) found diatoms
taken by herring larvae, but Bowers and Williamson (1951) did not.
Arthur (1956) considered Sardinops caerulea larvae to be carnivores,
less than 1% containing plant food, but Brevoortia larvae are supposed
to utilize diatoms (Harder, 1960). Morris (1955) suggested that the
ingestion of dissolved organic matter could be of importance to fish
larvae (Putter’s Theory), but to date little evidence is availabIe for or
against this.
The quantity of food taken waa found to vary with temperature and
size in Baltic herring larvae (Waldmann, 1961). Meyer (1878a) reported
herring larvae in his rearing experimcnts with as many a8 twenty
organisms in the gut. In rearing cxperimentn Blaxtcr (i!N2) fi)iiricl up
to ten organisms at any one time in larvae 10-12 mrri long f i r i d Kiirntts
(1959) found up to nineteen organimu takcri per day by f : l u p ~ ~
pulhu6
larvae 15-40 days old.
4. Digestion
JII hcrring larva0 tho food i s pnrmd almost immcdiatcly to the and
Iizukn el ul. (Bull. tlolskuido Rrg. FiNh. Res. Ln6. 25, 1-10. 1962) reportod an
incream in mouth size with growth but no great change in Him of food takon by larvne
of Clupea pallaeii.
J. H. 9. BLAXTER AND F. 0. T. H O U I D A Y
speoies seemed to feed only by day, indicating the importance of
vision.
3. Type and quantity of food taken
Bowers and Williamson (1951) and Bhattacharyya (1957) have
reviewed the large amount of work done on feeding of herring larvae
caught at sea from the analysis of gut contents. While it is not intended to discuss the results in detail, it may be said that the size of
food organisms taken seems to increase with the size of larvae and a
limited selection (or rejection) takes place. For example, organisms
such as the copepod Acartia, the diatom Biddulphia and dinoflagellate Ceratium, though present in the plankton, are not found in the gut.
As larvae grow older they tend to take larger food organisms.* The
apparently low percentage of larvae feeding reported by some authors,
though not for the larger larvae examined by Bowers and Williamson,
may be due to rapid digestion or defaecation on capture or fixation, or
to night sampling. Arthur (1986) suggested that mainly sickly or
starving Sardinqps caerulea larvae might be caught, giving a biased
estimate of percentage feeding. He also gave details of the feeding of
these larvae and showed how the size of food increased from up to Sop
when 4mm long to 200p when 10 mm long. Cushing (1960) also
described the increase in size of food taken by larvae of this species
as it grew.
The importance of phytoplankton for clupeid larvae has been under
discussion for many years. For example, Hardy (1924) found diatoms
taken by herring larvae, but Bowers and Williamson (1951) did not.
Arthur (1956) considered Sardinops caerulea larvae to be carnivores,
less than 1% containing plant food, but Brevoortia larvae are supposed
to utilize diatoms (Harder, 1960). Morris (1955) suggested that the
ingestion of dissolved organic matter could be of importance to fish
larvae (Putter’s Theory), but to date little evidence is availabIe for or
against this.
The quantity of food taken waa found to vary with temperature and
size in Baltic herring larvae (Waldmann, 1961). Meyer (1878a) reported
herring larvae in his rearing experimcnts with as many a8 twenty
organisms in the gut. In rearing cxperimentn Blaxtcr (i!N2) fi)iiricl up
to ten organisms at any one time in larvae 10-12 mrri long f i r i d Kiirntts
(1959) found up to nineteen organimu takcri per day by f : l u p ~ ~
pulhu6
larvae 15-40 days old.
4. Digestion
JII hcrring larva0 tho food i s pnrmd almost immcdiatcly to the and
Iizukn el ul. (Bull. tlolskuido Rrg. FiNh. Res. Ln6. 25, 1-10. 1962) reportod an
incream in mouth size with growth but no great change in Him of food takon by larvne
of Clupea pallaeii.