APPENDIX G _ 36 _ 



Tlie Norwegian fjords, the Skager E,ak, Kattegat and the Danish Belts and fjords stand 

 in close relation to the North Sea. 



Hjort and Da hi have already found from earlier investigations, that the cod also 

 spawned in the Norwegian fjords; they found pelagic eggs there, hut as a rule only very few 

 larvae, and the young Cod of the 0-group appeared first in autumn (September, October). In 

 our opinion they had wandered in there. 



The Danish Biological Station has during recent years continued the investigations on the 

 biology of the cod, carried out previously by C. Gr. Joh. Petersen. (Eeport XI, 1900 and 

 1901.) The essential results of these investigations, which confirm the earlier, are: 



1) that numerous cod spawn in the Kattegat and Belts; 



2) that the pelagic eggs and larvae of the cod are caught in the Belts, but that as a rule 



3) the Danish waters are in summer very poor in representatives of the 0-group, with 

 exception of some few places and with the reservation that the quantitative occurrence 

 is somewhat different in different years. Thus, for example, more young cod were 

 taken in 1902 than in 1901 and 1903. 



4) the 0-group first appear in late autumn in the same quantity as the I-group. 



A comparison of these relations in the years 1902 and 1903 is of importance. 



1902. During the spawning time of the cod, pelagic eggs were found in the Kattegat 

 and in the Belts in February, March, April even to the 14'^ of April. In May, the larvae 

 and young fishes also began to appear, and at the end of May a quantity of pelagic young 

 fish was found in the Little Belt. Pelagic cod appeared, though only in small quantities, in 

 the Belts all through June, and in the latter half of June bottom-stages appeared, even of 2 cm, 

 in length. In July and August, relatively few cod of the 0-group were found, in spite of 

 numerous searches in the Baltic, waters of Smaaland, the Sound and Ise Fjord; whilst in 

 September many specimens of the 0-group, in length from 7.5 — 12.5 cm., were taken in the 

 zostera-vegetation down to 36 m. deep, north from Pyen. 



Although the quantities of the 0-group found, cannot be called large altogether, the number 

 was distinctly larger than in the earlier observed years, and this year is thus an interesting 

 example of the change the quantity of young fish may experience in different years. It was 

 quite different in the year 1903. In March and April, spawning cod (of the Il-group, from 

 31 cm. on) were in the Great Belt. In April, the pelagic young cod began to appear, on the 

 surface as in the middle layers, in the Great Belt and Kattegat, especially in the waters on 

 the north coast of Zealand. In May, not a few cod of the 0-group (2 — 8 in one haul of the 

 sand-eel net) were caught in the Little Belt, in the middle layers at least 20 m. deep. In the 

 Kattegat a large quantity of pelagic' young cod was found in the middle layers ; once about 

 50 were taken in a haul with the sand-eel net, as a rule 2 — 5. Their length measured from 

 0.5 — 2cm, mostly 1cm. and under; some had still the yolk-sac attached. In the Great Belt, 

 some single specimens were to be found pelagically. In June, there were still pelagic cod in 

 the Kattegat, the largest 2 cm. long, as a rule 1 cm., some just hatched larvae were only 

 0.5 cm. long. In the Great Belt only a few were taken, yet some single pelagic young cod 

 occurred still in July, even on the 2°'i of August. In July, they began to appear on the 



