THE EEL-FARE 49 



To speak of the common eel as originally a deep-sea 

 fish requires, perhaps, the safeguarding statement, that 

 there is no reason to believe in the autochthonous abyssal 

 origin of eels. Before the eels colonised the great depths 

 they were probably littoral fishes, specialised for burrowing 

 in the mud, and for making their way through holes among 

 the stones. Perhaps this hypothetical, even more remote, 

 habitat has its organic reminiscence in the shoreward 

 migration of the glass-eels. 



To the question why eels which have reached repro- 

 ductive age in rivers flowing into the North Sea, for in- 

 stance, should travel far out into the Atlantic to spawn, 

 it may be answered that most parts of the North Sea are 

 too shallow, and where the depths are sufficient the tempera- 

 ture is too low. 



Let us revise the general sweep of the life-history of 

 this remarkable deep-water fish which has left the abysses 

 and has entered into intimate practical relations with 

 man. It probably begins its life below the 5oo-fathom 

 line on the verge of the Deep Sea in the stricter sense 

 that dark, cold, calm, silent, plantless world. It develops 

 and starts in life, and feeds and grows, far below the surface. 

 It rises to the upper waters as a transparent, sideways 

 flattened, knife-blade-like larva. It is gradually trans- 

 formed into a glass-eel with an energetic disposition, and 

 after about a year it is one of a million elvers passing up 

 a river. If it is not fortunate, it may take much more 

 than a year to reach the feeling-ground, for which it has 

 doubtless some organic, deeply sub-conscious desire; those 

 that ascend the rivers flowing into the Eastern Baltic 

 have journeyed over 3000 miles. Eventually they pass 

 up the streams, and there is a long period of growth in 

 slow-flowing reaches and in fish-stocked ponds. There 

 is never any breeding in fresh water ; but after some 

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