- 263 — 



In biological regard the eel must be considered as a true Atlantic deepwater 

 species, which in its biology only differs from its allies, the other Atlantic deepwater 

 species (e. g. Syniaphobraiichns pùiiiat/ts), in that it passes certain periods of its life in 

 shallow water. In this way in contrast to the other Atlantic deep-water eels it has come 

 to play an economic role for man. 



From the data to hand it appears, that the great majority of the West and North 

 European eels spawn at about the same time of year'. It is further certain that 

 the small, completely metamorphosed young eels of Stage 6, which occur in summer on 

 the coasts of North Europe, are considerably more than i year old, so that it is 

 therefore quite excluded that they can be the offspring of the eels which 

 have migrated out in the preceding autumn. 



It has been found that the male eel may exceptionally mature in shallow water, as 

 we know may be the case with the males of the conger [Conger vulgaris). Thus, A. 

 Feddersen on September ist, 1903 found in the shallow Prsesto Fjord in Denmark a male 

 silver eel, which was remarkable in having in addition to unusually large eyes, the testes 

 exceedingly large and quite filled with ripe sperms. This is the first quite ripe specimen 

 found anywhere of the European eel, though thousands of specimens have been examined. 

 Herein lies an indirect but undoubted proof that the eel does not spawn in shallow water. 

 It is only in shallow water that the eel has been sought for with suitable apparatus. 

 It now remains to seek for them in the deep water of the Atlantic, where our invest- 

 igations of its larvae have shown that they spawn. 



As to the importance of the present investigations in practical regard see Section III, p. 245. 



I We have thus seen that in the summer only Stage i was found and none of the later stages, in autumn 

 on the other hand the first stages in the metamorphosis, in winter only Stage 5 and so on. The French and 

 Spanish reports on the elver fisheries indicate clearly, that although the fishery begins in different months (Sep- 

 tember — December, January, February) at different places yet it ceases everywhere about at the same 

 time, namely at the end of April or beginning of May, the elvers then approaching the end of their mctamor. 

 phosis Similarly the English fishermen on the Bristol Channel say, that the elvers after April 30th become black, 

 bony and unsuited for food so that they no longer trouble to fish them These facts and many others clearly 

 .show therefore, that the majority of the elvers complete their metamorphosis at about the 

 same ti m e o f y e a r. 



