— 221 — 



•TOHS. SCHMIDT 



at station 10 (and at the earlier stations), while they were completely lacking at station 

 11 where we had a higher temperature though a very suitable depth. From this we learn 

 that here (the west coasts of the British Isles) it is only in the coastal regions where 

 temperature as well as salinity are comparatively low (see p. 115—116 and Fig. 4 p. 117) 

 that the propagation of the cod is able to take, place, and not further out to 

 sea where temperatures as well as salinities exceed the maximum-values for the spawning. 

 This point is undoubtedly of great importance and certainly deserves to be taken into 

 consideration in order to understand the distribution of the spawn of the cod and of the 

 young fry in the dift'erent parts of the waters W. of the British Isles (e. g. west and east 

 coast of Ireland). 



To judge from these last observations there is apparently every reason to wonder that 

 spawning takes place even as far out in the open sea as at Kockall Bank, where it is out 

 of the question that the low temperature and salinity of the coastal water from Scotland 

 can have any influence. On closer investigation however it appears that in spite of the 

 isolated position of this Bank out in the Ocean, there is at and around it a very peculiar 

 distribution of temperature and salinity which makes the spawning of the cod here com- 

 prehensible. In order to show this I may state my observations from the stations 14, 15 

 and 17, of which 15 lies on Rockall Bank itself while 14 is due E. and 17 due W. of 

 the Bank in almost the same latitude: 



From the above numbers we see that in spite of the oceanic position of Rockall Bank, 

 as far from the influence of the coastal water from the British Isles as the two other 

 stations, the temperature and salinity on this Bank are nevertheless considerably lower 

 than E. and W. of it. Taking e. g. the temperature at a depth of 100 m. (the depth in 

 which the cod is known to spawn), we see that on the Bank itself it is no less than ca. 1 

 degree lower than to the E. and W., and the salinity is also lower ^ It is thus seen 

 that this isolated Bank may to a certain extent be compared with the coastal belts near 

 the British Isles as regards low temperature and salinity, and it can also be observed that 

 while the temperatures E. and W. of the Bank exceed the level already on a former oc- 

 casion determined to be the maximum-value for the spawning of the cod (see p. 139), they 

 become lower on the Bank itself, where the eggs and fry were in fact found inside the 



1 A still lower salinity was found at Stat. 18 (57° 35' N., 13° 40' W.) also on Kockall Bank, viz. 

 35-21 »loo at the surface, 50, 75 and 100 m., while at a depth of 25 m. it was even 35-19 "loo. (Tempera- 

 tures; Om: 9°7, 25m; 9°1, 50m: 8°7, 75 and 100m; 8°6). 



