BULLETIN OF THE UNITED STATES FISH COMMISSION. Ill 



from Magnavacca and from Codigoro, on Chioggian vessels, and many- 

 times have fished myself, and have stimulated the fishermen by offers 

 of reward to endeavor to obtain eels at sea, but I am forced to the con- 

 elusion that with the ordinary means this cannot be done. 



"Intelligent, grey-headed fishermen of Chioggia, who by means of their 

 fishing apparatus know this part of the Adriatic as well as they know 

 their own pockets, have assured me that throughout their entire lives 

 they have never caught a grown-up river eel in the sea at any distance 

 fi'om the coast. The eels which were brought to me at Mannbach as 

 having been caught in the sea, and which I found to be the ordinary 

 females, or eels with the Syrskian organ, were either from localities close 

 to the shore where they are not rare, or were taken in the Palotta canal. 

 There was no lack of attempts at deception. Fishermen took eels from 

 the shore with them in order to be able, on their return, to claim that 

 they had been caught at sea. In the immediate neighborhood of the 

 coast they are, as it has been stated, in the spring-time not rare, and 

 there are not the slightest differences between these and the eels of the 

 lagoons. I found both females and eels with the organ of Syrski 

 with their re J) roductive organs in the same immature condition as in 

 Comacchio ; evidently the}' had just come through the Palotta canal 

 from the lagoon into the sea. A certain distance, perhaps one or two 

 marine miles from the coast, every trace is lost of the adult eels which 

 wander by the many thousand into the sea. Strange as this problem 

 ai^pears at first sight, it is easily understood when the character of the 

 fishing apparatus is considered ; the nets are those used in the capture 

 of lobsters, and are thrown over the bottom f they have meshes much 

 too large to hold the eels, or, when they are small-meshed, they do not 

 touch the bottom. The problem can only be solved by using" apparatus 

 constructed especially for the purpose." 



Jacoby proposes the following questions, which, in his opinion, cover 

 the still unanswered points concerning the natural history of the eel, 

 and answers them in accordance with the results of his own observations : 



Question 1. How can the fact be accounted for that no one has ever 

 found mature females and males, spawners and milters, among the eels? 



Answer. The eels require the influence of sea- water for the development 

 of their reproductive organs. As is now definitely understood, they leave 

 the rivers and the brackish lakes on account of the undeveloped condi- 

 tion of their reproductive organs, for the j)urpose of becoming sexually 

 mature at sea ; that these migrations to the sea take i^lace for the i)ur- 

 pose of reproduction aiopears to be certainly proved by the fact that the 

 young eels leave the sea in the spring, and that the migrating eels, like 

 other fishes at the spawning- season, abstain from earing. 



Question 2. When and where occurs^ the necessary development of 

 the reproductive organs of the eel to a condition in which they are 

 capable of fertilization ! 



Answer. Development of the reproductive organs takes place in the 



