INTERNATIONAL FISHERY INVESTIGATIONS 599 



characterised by the presence of cod-fry of different degrees 

 of development. By-and-by these little cod disappear from the 

 surface of the sea — it may be at a distance of about 120 nautical 

 miles from the place where they were hatched — and settle down 

 to their demersal stage of existence at the sea bottom. This 

 is the outline of the life history of the cod shoals which inhabit 

 the Lofoten banks at the spring of the year ; but corresponding 

 investigations carried out in the North Sea, the Cattegat, and 

 other regions have shown that the course of things is not 

 always the same in other regions. The size of the spawning 

 adult fishes is slightly different in these fishing grounds; the 

 time of spawning is also different. It has been found, for 

 instance, that the cod may spawn in some parts of the North 

 Sea in the autumn ; the distribution of the fry and the size of 

 the latter, when it first seeks the bottom, may also vary. All 

 these varying relationships of the adult fish to spawning-places, 

 to depths of water, to currents, and the time of spawning, as well 

 as the time taken for the young fish to assume the demersal 

 habit, are essential for such a comprehension of the natural 

 conditions of the fisheries as is necessary for the purposes of 

 legislators. Most fisheries laws are, in fact, local ones, and 

 must be founded on the conditions of the area to which it is 

 intended to apply the legislation. 



It has been the aim of these international investigations so 

 to co-ordinate them that there is no unnecessary duplication 

 of the researches. Just as the English and the Dutch have 

 devoted particular attention to the study of the plaice, and the 

 Norwegians to that of the cod, so the Danes, while by no means 

 restricting their work, have been assiduous in the attempt to 

 elucidate the life history of the fresh-water eel— a fish which 

 has considerable importance for Danish fishermen. It has long 

 been well known that the eel does not spawn in fresh water, 

 but, after passing a certain time in the rivers, assumes a " bridal 

 dress" of bright scales and descends to the sea. So much we 

 have known for a considerable time, and we also know from the 

 now classical researches of Grassi and Calandruccio in the 

 Mediterranean that the eel goes down into abysmal depths 

 before it deposits its eggs. It has been assumed rightly that 

 the same process of spawning also takes place in our more 

 northerly latitudes, that the eel also goes away somewhere 

 into deep water to reproduce. But this is entirely an inference 



