12 



North Europe, that the solution of the problem was arrived at. In tb.e mouth of 

 May 1904 Dr. Jolis. Schmidt found the first specimen of Leptocephalus brevirostris 

 pelagically in the ocean S. W. of the Færoes, and in the following year was suc- 

 cessful in proving tlieir presence in quautities iu the deep Atlantic waters, West 

 and especially S. W. of Ireland. (See C. G. Joli. Petersen: Larval eels (Leptoce- 

 phalus hrevirosfris) of the Atlantic coasts of Europe. Særtryk af Meddelelser fra 

 Kommissionen for Havundersøgelser. Serie: Fiskeri, Bind I, 1905; and also, Johs. 

 Schmidt: Contributions to the lifehistory of the eel (Anguilla vnlgaris, Flem.) 1906). 



Thus the spawuiug place of the eel was found; we know where the silver 

 eels are going to when they leave cur fresh and salt water in autumn, and we 

 know whenee the couutless swarms of montée (elvers or glass-eels) come which 

 appear on our coasts in spring. 



The question still remains whether the eels there lay eggs or are vivi- 

 parous. This has not yet beeu auswered directly but the great probability is that 

 the eel lays eggs; (he structure of its ovary with the enormous number of eggs 

 speaks in favour of this. 



The silver eel does not return from its spawning place — probably it dies 

 immediately after its first spawuiug period. — — 



As can be seen from this brief summary, the main features in the life- 

 history of the eel are quite well known. Twice duriug its lii'e it actually under- 

 takes the long migrations from and to the Atlantic Ocean, and though it is difficult 

 to understand how such tiny creatures as the small elvers (moutée) can traverse 

 such a great distance as is liere in question, yet it is nevertheless a faet. 



In the intervening period between these migrations, elver-migration and 

 spawning-migration, the eels live in fresh Avater or in the sea in shallow water; 

 duriug this period they feed and grow and may not be regarded as the adult fish 

 before it assumes its breeding-dress; tlien it ceases to take food and migrates out 

 towards its spawning place. 



How great is the period, how many years lie betweeu the two 

 great migrations of the eel? 



How old are the silver eels when they leave these waters as adults? 



This is a question which has great importance for all interested in the 

 eel-fisheries ; and their number is very large, not least in Denmark. It is iudeed 

 a well-known thing that eels occur iu our freshwater and in the waters of little 

 depth around our coast in very great numbers, especially where the bottom in the 

 latter case is covered with zostera — the eel-grass, as it is generally cailed by the 

 fishermen. The eel-fishery is carried on with the most different kinds of apparatus 

 throughout the year; there is no cessation as is the case in our other tisheries. 

 A sketch of how it is carried on in one of our larger fjords is given by C. G. 

 Joh. Petersen in the Report of the Biological Station, I. 1890 — (91). This gives 

 an idea of the intensity with which it proceeds, and one can understand that great 

 economic interests are bound up in it. The question of the growth and age of the 



