3IO 



DISCOVERY REPORTS 



accurately gauged without weight or volume records and altogether more extensive data, but a system 

 of arbitrary' weighting (kept well on the ' safe side ') permits a diagrammatic presentation of seasonal 

 changes in the major (lumped) categories, that gives a useful general picture. It may be regarded as a 

 cautious understatement of the predominance of fishes and cephalopods in the diet, and of the 

 obviously great importance of Chipea, especially in winter. The 'weighting' employed, after due con- 

 sideration of known weights of most of the food organisms was : regarding Crustacea and benthos as 

 unity, cephalopod records were multiplied by four and fish records by five. The results are shown in 

 Fig. 26. Doubtless this picture would be altered by more detailed results, especially if the size of the 

 fish could be taken into account, but such work will only be possible when a naturalist can devote his 

 whole time to the one problem. 



A B C 



Fig. 26. Diagrams showing crude relative proportions (arbitrarily weighted) of the main food categories of Merlucdus huhbsi 

 at different seasons. Weighting: fish x 5, squids x 4, Crustacea x i, and echinoderms, etc., x i. Echinoderms, etc., which are 

 rarely eaten are left white in the diagrams. A, third survey, summer. B, first survey, autumn. C, second survey, winter. 



PARASITES 



Like most other sea fishes M. hubbsi were observed to be very commonly infested with nematode, 

 cestode and trematode worms. On the first survey these three classes of parasites were observed to be 

 present in (roughly) the order of frequency in which they are named above, and it was noted that they 

 seemed particularly abundant in the larger (older) fish. Almost all the specimens examined had 

 nematodes in some part of the digestive tract or in the body cavity. Copepodan parasites were 

 evidently less frequent but not uncommon. Chondracanthidae were more than once recorded as 

 numerous in the mouth, and Miss N. G. Sproston informs me that members of this family frequently 

 infest European hake also. 



There aje numerous references to Lernea and Lerneidae in the log-books, which introduce an un- 

 fortunate element of doubt into some carefully collected statistics of the incidence of this form of 

 parasitism during the third survey, when the hake were sorted into length classes for weighing. I 

 believe that these records all refer to a lernaeocerid either identical with our own Lernaeocera branchialis 

 or very closely allied to it, but earlier references to ' Lernea ' on external situations (L. branchialis is 

 strictly a blood-vascular parasite, and has been recorded from European hake) leaves some element of 

 doubt. The situation is clouded by the unfortunate change of status of the genus Lernea so justly 

 deplored by Gurney (1933, p. 336). To be quite safe, these parasites may all be referred to the family 

 Lernaeoceridae as proposed by him. 



The bulk of the figures were obtained in December, in the northern and intermediate regions, that 

 is, in the most favourable part of our area for hake, at a time when the seasonal shoreward migration 



