s;} 



Emigration from fresh and brackish Water to the Sea for the sake 

 of spawning is not an exceptional phenomenon among our fishes. 



That the eel in its silver dress eniigrates to tlie sea in great numbers has 

 l)een known by everybofl}' from time immemorial, and great Hslieries and 

 iuterests have always been attached to this migration; the silver eel goes out 

 of our fresh waters as well as along our shores, and the ydlon- eel does nof 

 folfow it on this migration. These ai-e long-established facts wiiidi in tiieni- 

 selves fully jirove that tJie yelhjw eels become silver, particularly after it had 

 )>een prettj- unanimously agreed upon that \ve liad to do with only one species 

 of eels; nobody, however, had taken the tronble more closely to examine this 

 circumstance and show what is hidden bchind the Hshermen's names »yellow>< 

 and »silver«. 



The silver eel's great migration has, at least since v. Siebold's time, and 

 surely most justly, been supposed to be connected witli tJie ])reeding of the 

 eel in the salt water, of which, after all, we do not know ranch ; but the brood 

 whieh in spring has immigrated into the inshore seas and fresh waters is 

 evidence, however, that such a breeding has taken place. 



When the direction in which the migration goes has generally been 

 looked upon as an erception from the hreeding-migrations of othcr fishes, which 

 from the sea approach the shores or go into fresh water, while the eel irilJi- 

 draws from the shores and the fresh teater, this is in my opinion quite un- 

 justified. The breeding-migration of the eel fully agrees with the migrations 

 ol' several others of our commouest salt-water fishes, for instance plaiee aud 

 floimder. 



That fishes as troid, salmon, and various others, which sjiawn in fresh 

 water, during the lireeding-time go up the rivulets and brooks from the sea 

 cannot surprise; they must he look^å n^on &h fresh-tvater fishes which have 

 accustomed themselves ui certain periods of theii- lives to seeking their food in 

 the sea; but by theh* breeding and their tender fi-y they are firmly attached 

 to fresh water whieh, therefore, they cannot at all dispense witli. 



Equally easy is it to understand that salt-vatcr fishes as the herrin;/ and 

 the garfish, whose eggs are deposited on tlie hof tom of the sea on shalloir water, 

 in breeding-time generally approacli the shores, as their eggs and fry cannot 

 live at auy other piaces. 



That fishes whose eggs, on tiie other band, //o«/ orhnoij in the irater ahomnst 

 go to such [ilaces as are suitable for the develojiment of their eggs, i. e. piaces 



5 



