478 



Transactions. 



Table VII. — General Analyses showing Seasonal Variation of Groper and 



Kingfish — continued. 



p. 

 no 



Date 

 received. 



1/2 



60 

 C6 



o 

 Cm 



r/i (Vj 



°o-3 



60 



S3 



60 



o « 



Ph 



Cost of 



1,000 



Calories. 



(Pence.) 



Kingfish. 



Discussion. 



It will be seen that the fat content of groper varies during the year 

 from 1-90 to 7-63 per cent., while that of kingfish varies from 0-54 to 6-79, 

 so there is considerable variation in the nutritive value. This is well 

 shown by comparing the total calories per 100 grammes of fresh material : — 



Fish. 



Groper 



Kingfish 



Fat. 

 (Percentage.) 



1-90 

 7-63 

 0-54 

 6-79 



Calories. 

 (Percentage.) 



96-39 

 152-30 



76-75 

 159-44 



The nutritive value of a fish at its best is double that of --the fish in poor 

 condition. When the high nutritive value of the roe is considered (calories 

 per cent, of roe = 200), the low food value of fish after spawning is not 

 remarkable. 



Groper came into the market heavy with roe in July and August, but 

 kingfish was hardly procurable in those months. The analyses give point 

 to the probability of the spawning season for kingfish being in February 

 or March. 



The variations noted may be due to differences in age, sex, metabolism, 

 richness of feeding-ground, or other causes, so that more must be known 

 before the differences can be taken to represent seasonal variation alone. 

 Were a sample taken from the mixed muscle of a number of fish, as in 

 the case of whitebait, discussed above, some of these variations would be 

 eliminated. The market, too, presents difficulties. The fish are not pro- 

 curable at definite stated intervals. The results, however, embody the 

 variation in the value that the consumer is obtaining when buying the 

 same variety of fish at different seasons of the year. 



All the expenses incurred in these investigations have been defrayed 

 by a grant from the New Zealand Government, through the New Zealand 

 Institute, and I have to thank the Universitv of Otaso for the use of 

 laboratory-space and apparatus. 



