— 39— JOH.HJORT AND C.G.JOH.PETEESEN 



conclusions on many experiences, observations and marking-experiments, as in the case of the 

 plaice; we are chiefly dependent on a summary of the results of the many fishing experiments, 

 which have been made at all times of the year and in the most different regions of the sea. 



With regard to the North Sea, Henking has given Committee A some time ago, 

 numerous statistical data which he collected with regard to the catches of trawlers of the Ger- 

 man fishing port, Geestemiinde, and he has added to his material a manuscript, in which he had 

 made a summary of the results to be obtained from the data, according to his opinion. He distin- 

 guishes between large and small cod. The large have a weight of 2.5 to 8.5 kg, on the average 

 4.8 kg, and a length between 65 and 99 cm. The small cod weigh between 0.12 and 2.8 kg., 

 on an average 0.6 kg; the length, 26 to 68 cm. On the off-banks with depths of 40 — 70 m., 

 the difference in the number of pounds per day of voyage is relatively small the whole year 

 round. In the six months of winter, the average number amounted to 275 ft per day. In the 

 six months of summer it was somewhat larger, viz. 341 fî per day. 



The relation is different on the coastal banks with depths of 20 to 40 m, namely 465 fb 

 per day in the six months of winter and only the half of this in the summer six months. 

 Also, if we consider the relation between large and small cod on the banks at the different 

 periods of the year, a movement of the fish-masses towards the banks becomes evident. On the 

 deep banks, the average proportion by weight between large and small cod is 1:1 in summer, 

 whilst in winter it changes to 2.2 : 2, on the Dogger Bank even 6:1. Still more impressive 

 is the proportion on the coastal banks, it is 1 : 1 in summer, which in the later months of 

 winter, increases to 12 : 1 in the special spawning places. 



The Scottish statistics chiefly represent catches from the north-western portion of the North 

 Sea, thus supplementing the statistics of other countries. They have been worked out in detail 

 by d'Arcy Thompson, especially for the coastal banks of Scotland. With regard to this region 

 of the North Sea, it may be said that a distinct tendency to form two maxima can be 

 detected, one during the spawning-time and one during the months of July and August. The 

 latter maximum coincides with the appearance of the herring-shoals. 



These changes in the occurrence of the various sizes of the cod, can also be shown from 

 the numerous catches of the research-steamers. They are specially clear in the catches of the 

 English steamer "Huxley". 



This must occur to even greater extent in the Norwegian Sea, as the cod forms there the 

 most important portion of the catch. The variation in the appearance of the cod-shoals there, 

 has for a long time astonished both fishermen and scientific investigators alike. 



What chiefly determines the fisheries of the Norwegian Sea are the migrations of the 

 cod, and it is characteristic there, both in Norway and at Iceland, that the cod are cauglit 

 in geographically different regions at different periods of the year — during tlie spawning time 

 and in the summer. 



If we investigate the stock of large cod in the Norwegian coastal waters out of the 

 spawning time, e. g. in the summer, we find but very few cod along tlie whole stretch from 

 Tromso in the north, down to the North Sea. Thus, fishing with several millions of hooks on 

 the Romsdal banks in summer, only one cod to 700 hooks was taken. Up to the present, 

 there has never been so great a fishery on this long stretch in summer, that any trade worth 

 mentioning developed from it, apart from supplying the market in the small towns and the 



