— 126 — 



minations show that they begin to spawn already \vhen 3 years old, and that half the 

 four-year-olds and all at five years spawn. 



On the west coast the 0-group is very much smaller than in the North Sea or 

 Skager Rak. At the beginning of June the small fish are on an average 4 cm., in 

 September 6 and in October 6—7 cm. in length. The trap nets in the strand-region 

 take all sizes from 21 — 100, chiefly however from 30—60 cm. long. To the sizes 

 from 30 — 60 cm. correspond the year groups of 272 — 672 years, the ab- 

 sence of the larger fish is due to the lack of individuals over seven years 

 old. What is characteristic of the growth is an extremely great variation within 

 the separate year-groups. In one sample, for example, there was a difference of 

 24 — 65 cm. amongst the 4Y2 year old fish. See fig. 49 with graphic representation of 

 the size-groups of different ages from the catches in trap nets during summer to autumn. - 



It is also just as important a fact, that there is a considerable difference in size 

 between the individuals from different regions. The largest are found on the 

 open coasts, the smallest in enclosed Qords. By means of the age determinations it was 

 possible to prove that wherever the individuals were smallest the growth 

 was also least; the specimens are not smaller because they are younger. Further, 

 maturity in the cod of the west coast taken in trap nets begins already in some at 

 an age of 3 years, in several at an age of 4 years and in practically all at 5 years. 



Analyses of the age were also made in the case of the Fin mark cod (fig. 50) and 

 showed that the great majority consisted of younger individuals of the same age as the 

 trap net cod, up to and including 6 years. In the younger year-groups the Finmark 

 cod is considerably larger than the trap net cod. More and more "summer fish" arrive 

 at Finmark in the course of the summer, coming probably from the spawning places 

 lying further to the south. 



In connection with this we may refer to some analyses of the age of cod taken by 

 the "Michael Sars" in August 1907 north of Cape Kanin in the Barentz Sea, north of the 

 White Sea. Amongst these were some fish three years old which were only 19 to 

 24 cm. and some five years old which were only 31 cm. in length. The scales showed 

 that the growth in the first year had been very small, that the winter rings were exceed- 

 ingly well-marked, so that the fish had thus scarcely grown in the winter, and that the 

 winter condition had already begun in August 1907 for the fish then over two years old. 

 Thus, the summer was already over in these northern waters. 



The Skrej. On fig. 51 5 curves are given which represent the sizes of spawning 

 cod taken in spring in 5 hauls; Nos. I — 3 from the Norwegian coast. Nos. 4 — 5 from the 

 North Sea^ 



No. 1 is from the Malangs Ground at 70° N. L. 



— 2 — Lofoten about 68° N. L. 



— 3 — the Romsdal Bank a little north of 62° N. L. 



— 4 — Shetland about 60° N. L. 



— 5 — the central part of the North Sea about 57° N. L. 



I The North Sea curves have been drawn from the measurements received by the Committee of "cod" 

 from the catches of Scottish steam trawlers. 



