ADULT HEKKINGS 165 



Age Distribution in the Shoals 



By studying the scales Hjort and Lea are able to say what 

 proportion of fish hatched in any particular year are contained 

 in a haul, and this can be determined especially easily off the 

 Norwegian coast, where herrings are caught in seine-nets which 

 retain fish of all sorts and sizes. Drift-nets and trawls do not, 

 of course, catch fish below a certain size, and are consequently 

 much less useful than purse-seines for purposes of herring re- 

 search. A haul in the spring of 1907, for instance, gave Hjort 

 924 fish ; the vast majority were from four to eight years old ; 

 very few indeed were as young as three years old, and none 

 younger ; there were rather more ' nine-year-olds ' and ' twelve - 

 year-olds ' than ' three-year-olds ' ; and very few of ten, eleven, 

 and thirteen years. Four-year and eight-year-old fish pre- 

 dominated over all other years. 



Amongst other things, Hjort from these observations 

 ' definitely settled for all time ' that Norwegian herrings spawn 

 from three years to at least fourteen years of age ; and that 

 the ' matties ' or maiden fish are between one and a half and 

 four years old. Following up this fine of investigation, Hjort 

 and Lea have proved that the ' fjord herring ', the ' large 

 herring ' caught off Eomsdal in late autumn and winter, and 

 the ' fat herring ' caught off the northern coasts in autumn, are 

 all fish spawned off the south-west coast in the spring, at 

 different stages of their development. 



They found that the 1904 brood, Hke that of cod and haddock, 

 was especially plentiful. It was, moreover, quite peculiarly 

 marked by a very small growth in its third year.^ This brood 

 was confined to the north coast of Norway in 1907, and up to 

 September 1908. Li the autumn and winter of 1908-9 and 

 1910 some of them appeared among the ' large herring ' off 

 Eomsdal ; and in 1910 they made their first appearance among 

 the spawners on the south-west coast. They were then in their 

 sixth year ; and in course of the year they were caught in the 

 Faeroes, the Skagerrak, the Kattegat, and in the southern 

 portion of the North Sea. Their numbers were so great that 

 even last year (1919) these 1904 fish formed a large proportion 

 of the Norwegian catch, though they were then fifteen years 

 old. On the other hand, the spawning seasons 1905 to 1909 

 inclusive appear to have been much less productive. 



In 1913 Dr. Hjort found immense numbers of one-year-old 

 herrings and cod which had been spawned in 1 91 2, and this brood 

 began to appear in large numbers in the catches at the end of 



* Depths of Ocean, p. 765. 



