56 Fart III. — Tiventy -seventh Annual Eeport 



Quantity of Abdominal Fat in Immature Herrings in February. 



Most of the larger immature herrings, i.e., from 13 to 23 cm., have very 

 much fat. They form the first summer-spawning group. The herrings 8 

 to 17 cm. long, which have "no fat," are, I believe, a group of herrings six 

 months younger than the first. The small herrings 8 to 10 cm,, which had 

 " much " and " very much " fat, constitute a difficulty. They are too small 

 to belong to the first summer-spawning group. 



Herrings which have already spawned also become apparent " matje " 

 herrings. Six months after spawning they have laid up fat in great 

 quantity, and the reproductive organ has shrunk to a small size. Huxley 

 said that if the spent fish escapes its myriad enemies, it doubtless begins 

 to feed again, and once more passes into the "matje" state in preparation 

 for the next breeding season. Sim questioned this statement. He 

 maintained that a fish that has once sp.awned cannot return to the "matje" 

 condition, which is strictly that of heriing that has not yet spawned. In 

 this I think Sim was right. I am of the opinion that "matjes" which have 

 spawned before have a deeper body than true " matjes " (Immatvu^es). 

 But, on the other hand, the veiy small reproductive organ might pass 

 for an immature organ^ and the fish would be accepted for trade purposes 

 as a " matje." This condition is noted in summei-, specially in connec- 

 tion with the winter spawners. The " matjes " which had been summer 

 spents no doubt exist, although they are not fished. 



The reproductive organ now starts to develop. It grows at the expense 

 of the fat rolls. It seems to be able to divert all nutrition to itself, and to 

 deplete the general tissues, if necessary, in order to get the necessary 

 nourishment for its ripening ova. The extent to wliich the general tissues 

 will be drawn upon will depend on the quantity of food available for the 

 herring during the period. The summer-spawning herrings are better 

 situated during that time than are the winter spawners. But from the 

 fact that the herrings appear in February with lai'ge quantities of abdom- 

 inal fat, it is evident that the herrings must, during the winter, have a 



