— 92 — 



curred at these three Shetland stations late in July 1905, for example, the young of 

 the blue ling and of Lophius piscatorius which according to our investigations spawn in 

 the Atlantic deep water and whose pelagic eggs and fry are found in quantities along 

 with the larvae of the eel (Leptocephalus hrevirostris)^. 



The pelagic invertebrates found at these stations round about the Shetlands also show, 

 that there is here an unusually extensive migration of Atlantic organisms. Thus, a haul 

 of half an hour at St. 121 contained over 700 liters of Salpœ (Salpa and Doliolum) in addition to 

 other true Atlantic organisms, such as Collozoum, Cleodora, Arachnachthis etc. which we 

 were accustomed to get in quantities in our hauls over deep water in the Atlantic W. of 

 the British Isles. And in the quiet weather we could see the water filled with innumer- 

 able Salpse, both long chains and singly. Under these conditions I believe that the few 

 Gadiculus young came from the Atlantic, like all the unusually many Salpse etc. And it 

 should also be remembered here that the Shetlands are washed by that part of the At- 

 lantic current which provides the Norwegian coast and the Norwegian Sea with Atlantic 

 water, and the velocity of the current is there specially great. 



Summing up the available information I conclude that Gadiculus certainly does not 

 reproduce in the whole of the southern and central parts of the North Sea and probably 

 also not in the northern, at least only to a very small extent. On the other hand there 

 is in all probability a drift of the pelagic fry of Gadiculus from the Atlantic into the 

 northernmost parts of the North Sea in summer (and autumn) ^. 



5. The Channel 



In spite of our numerous hauls in the Channel, in April, May, June, August and 

 September, the pelagic young of Gadiculus have never been taken, nor is there any sign 

 of them in the samples sent me from the Plymouth Laboratory, or in the lists already 

 cited of Holt and Scott. From this we may conclude that Gadiculus argenteus does not 

 reproduce in the Channel, which might indeed have been expected beforehand from the 

 shallowness of this region. 



6. Bay of Biscay 



Our investigations in the beginning of May 1906 show that the pelagic young of 

 Gadiculus occur in the neighbourhood of the 1000-meter line, both in the northernmost 

 and southernmost parts of the Bay, although only in small quantities, but perhaps the 

 small numbers must be ascribed to the fact that the spawning time in the Bay is 

 somewhat earlier than further to the north, so that we were too late to capture a larger 

 number. 



As the species occurs in the Mediterranean (from which I have seen some specimens), 

 it is evident that the fry will also be found further south In the Atlantic than we have 

 worked, for example, off the coasts of Portugal. 



' I shall give a report later on the biology of LopMus piscatorius. 



^ The Skager Rak was investigated in various directions at numerous (ca. 35) stations by the "Thor" 

 in June and July 1907, both in shallow and deep water. As we did not obtain a single specimen of the 

 pelagic fry of this species, we may conclude that Gadiculus, which in any case does not seem to be very 

 common in the Skager Eak, only reproduces there at the most to a very small extent. 



