[5] EEL-FISHING IN THE BALTIC. 419 



;iu(l it tlierefore seems that in otber countries such migrations do not 

 occur. Loberg' speaks of a kind of eel-fislieries with a sort of fish-pots 

 on the coast of Norway, and mentions that there, too, the eels go in a 

 southerly' direction, but from his remarks it appears that these fisheries 

 are only carried on near the mouths of rivers.* Kroyer supposes that 

 the object of the eel in wandering along the coast is to seek deeper and 

 Salter waters, and that those eels which pass the coasts of Denmark 

 are principally fresb-water eels from the rivers Oder, Vistula, and other 

 rivers flowiug into tbe Baltic. t He does not state, however, in bow 

 far he considers salt water necessary for the spawning of tbe eel. If 

 this view of Kroyer, that tbe eels seek Salter waters, is correct— and in 

 itself it seems highly probable to suppose that salt water is of the same 

 importance for the development of the spawn of the eel, as fresh water 

 for the development of the spawn of the salmon and other fish, as other- 

 wise tbe migration of the eels from the rivers into the sea seems utterly 

 inexplicable — we can easily explain why tbe migrations of the eels along 

 the coast are noticed particularly on the coasts of tbe Baltic, and espe- 

 cially in tbose parts of this sea which have an immediate connection 

 with tbe Salter waters of the Kattegat, but not on the coasts of England, 

 France, or Italy, which countries are surrounded by waters which are 

 a great deal Salter than the Baltic. Loberg's statement, referred to 

 above, regarding the migrations of the eels on the coast of Norway, 

 seems to speak against this view, but as the migrations of the eels are, 

 in Norway, confined to the mouths of rivers, this statement does, in my 

 opinion, not disprove the assertion that the saltness of the water is the 

 cause of tbe migrations of the eels along the coast. 



In bis description of the large and well-known Italian eel-fisheries 

 near Comacchio,| Jacoby expresses tbe opinion that the migration of 

 tbe eels into the sea, or the so-called "calata," is favored by the circum- 

 stance that when in summer the water evaporates, the saltness of the 

 lagoons becomes too great, for which reason the eels eagerly seek the 

 sea-water, which is less salty — an opinion entirely ojiposed to the one 

 expressed above. The spawning process probably is the principal 

 cause, particularly as the lagoons of Comacchio hardly contain any 

 suitable spawning places for eels. It would, moreover, doubtless be 

 an error to explain the migrations of the eels as exclusively depending 

 ton the character of the water, as, like the migrations of other fish, they 

 are also caused by other circumstances, which are not yet fully under- 

 stood, and which may be comprised under the head of what is called the 

 '' migratory instinct." But whatever may be the causes of the migra- 

 tions of the eel, I think that it is evident from what has been said above 

 regarding the eel-fisheries on the Baltic coast that such migrations take 

 place, and that a more thorough investigation of these fisheries, even 



"Norges Fiskerier, 1864, pp. 298, 299. 



WanmarJcs Fislce, vol. iii, p. 6.36. 



t"Z)e?- Fischfang in der Laguv.e von Comacchio, ^c," Berlin 1880, p. 75. 



