Lebour. — Food of Larval and Post-Larval Fishes 349 



known to be the case with the flounder whose feeding habits 

 are interesting. Several of the young pelagic stages from 10 

 to 11 mm. were found to be eating Phseocystis which occurs 

 very abundantly in Plymouth Sound in May and June. Some 

 of these were kept in aquaria and fed on Phaeocystis which 

 they ate until they began to feed on the bottom. When still the 

 same size they changed their diet and fed on copepod nauplii 

 and later on they took small copepods, chiefly Pseudocalanus. 

 Specimens of 11 mm. from one of the estuaries having already 

 metamorphosed, were feeding on small harpacticids, and still 

 later stages in the estuaries from 20 to 30 mm. were feeding 

 on harpacticids in the bottom mud. The change of diet is 

 thus coincident with the transition to the bottom stage. 



Young pelagic brill, 4.5-6 mm., were eating copepod 

 nauplii, also eggs (probably copepod). The brill migrate 

 shorewards and at the water's edge, those from 10 to 13 mm. 

 being then in the bottom stage, eat principally larval mollusks. 

 Older specimens of from 20-30 mm. feed chiefly on young 

 fishes. 



The young gadoids are all specially fond of Pseudocalanus. 

 The whiting {Gadiis merlangus) , being the commonest in this 

 area, was the species chiefly investigated. By far the greater 

 number of specimens had eaten Pseudocalanus, many hun- 

 dreds, from 3 to 20 mm. long being examined, besides some 

 adolescent stages. Below 5 mm. copepod nauplii are chiefly 

 taken, after this size adult Pseudocalanus may be eaten. 



Some young whiting were kept in aquaria and their feed- 

 ing watched. It was found that if several species of copepods 

 were given, they always went for Pseudocalanus first, Acartia 

 next, Calanus being taken before Temora, which agrees with 

 what is found by examining the insides. Calanus is usually 

 taken by the whiting in early summer when Pseudocalanus is 

 scarce. Specimens of 22 mm. can eat small fish, although cope- 

 pods are often taken up to 60 mm. or more, with decapod 

 larvae. Still older specimens eat fish habitually. 



All the other common gadoids Gadus pollachius, G. min- 



