518 



U. S. BUREAU OF FISHERIES 



tlio jnaxixnum about ihe first week in Soptoinbor and drops off agaii^. 

 like the albacoro. 



In Table 12 Dill (1921a) presents a special study ol the variation 

 of the average monthly composition ot the larger-sizMl California 

 sardines which are used in packing poimd oval cans. We have in 

 this table data running through two years, based upon analyses of a 

 considerable number of fish caught at monthly periods during the 

 seasons when the sardines arc present in considerable numbers off 

 the southern California coast. 



Table 12. — Monthly average composition of "large oval" size sardines caught 



off the coast of California 

 [Analyses of the edible portion on the fresh basis] 



Month 



-1»19 



January 



•February 



March 



April 



May 



Decern ber 



1920 



January 



February 



March... 



April 



May 



June 



Number 

 of analy- 

 ses 



Total 

 solids 



Per cent 

 37.71 

 33. 34 

 35.41 

 21.08 

 23.27 

 40. 30 



37.91 

 38.34 

 3C. 53 

 27.52 

 25.78 

 25.22 



Per cevl 

 19.20 

 14.02 

 15.83 

 .75 

 2.74 

 21.38 



17.89 

 18.88 

 17.04 

 6.67 

 4.00 

 2.75 



Protein 



(NX6.25) 



Per cent 

 17.44 

 18.00 

 18.06 

 18.93 

 19.07 

 18.00 



19.00 

 18.06 

 18.06 

 19. 25 

 20.75 

 21. 13 



Fuel 



value per 



pound 



Calories 



1,135 



927 



1,004 



669 



470 



1,237 



1,108 



1,133 



1,055 



639 



555 



Again, using the percentage of fat as an index of the variation 

 (and that is fair because, as we have already pointed out, the per- 

 centages of ash and protein do not vary greatly for one reason, 

 and for another it is the changes in fat content that cause the 

 greatest variation in fuel value per pound) , we see that there is a 

 marked cycle of variation in each year. During January, February, 

 and March these sardines are at their maximum degree of richness — 

 namely, have an average fat content of about 17 per cent. However, 

 in April, May, and June, the cycle swings downward and the per- 

 centage of fat decreases to an average of only 3 or 4 per cent. This 

 is a very great change in composition and has considerable economic 

 significance because the large oval sardines are packed in tomato 

 sauce and not oil and for that reason must be packed at a time of 

 the year when the fish are at the maximum degree of fatness. This 

 has been found by experience to be duiing the winter and early 

 spring. 



In Alaska there is a somewhat similar variation in the composition 

 of herring, on which a large industry has been founded in preserving 

 the fish by the Scotch-cure method. It is during the season of the 

 year when the fish are in the stage of maximum fatness that most of 

 the vScotch-curing operations are carried on. We see, therefore, that 

 the question of seasonal variation of fish is one not only of importance 

 to the consumer from the standi)oint of calories obtained for a given 

 unit of expenditure, but also that large industries with many milhons 

 of dollars involved and many peojue em])loyed must shape their 

 operations in accordance with variations in the composition of the 

 fish. 



