390 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



the wind the richer the yiekl, provided that a sudden storm does not 

 destroy the fishing apparatus before the eels have begun to move. 



The migration of the eels in autumn is carried on during the night, 

 beginning about one hour after sunset; is strongest from midnight till 

 2 o'clock in the morning, and ceases about one and one-half hours before 

 sunrise. Views are greatly divided among fishermen as to whether, 

 during day-time, the eels hide among tbe aquatic plants near the shore, 

 or whether they stay in deep water at a greater distance from the coast. 

 As far as my own observations go, I am led to suppose that during 

 day-time the eels only avoid the shallow places where there is but little 

 vegetation, but that as a general rule they keep at no great distance 

 from the coast, in order to continue their migration in the evening. 



This migration is going on the more cautiously the calmer the weather, 

 and for this reason mauj eels cannot be caught in standing apparatus 

 during calm weather and in clear water. I thus remember that during 

 a beautiful but very dark September night 100 eels were caught with 

 a small net at a single haul, near a large number of fish-baskets from 

 which the following morning only from 15 to 20 eels were taken, although 

 it is certain that many eels were constantly passing the baskets. 



To watch the eels among the fish-baskets along the coast, select a 

 very dark autumn night, when the sea is strongly phosphorescent and 

 when there is absolutely no wind, or the evening twilight soon after 

 sunset, and full opportunity will be afforded to observe the life and do- 

 ings of the eels. It is only under very peculiar conditions of weather 

 that the eels migrate in large schools. It is probable that when the 

 sky is thickly clouded — but even then only during a storm — the largest 

 schools move along our coast, although large masses have been observed 

 in various places during calm weather. In the autumn of 1879 I ob- 

 served soon after sunset a large school of eels in the Little Belt whose 

 appearance astonished me very much. When later I mentioned it to 

 the fishermen of the neighborhood, I was told that the eels often formed 

 an immense ball, rolling along the coast towards the north. There can- 

 not be any doubt that this migration towards the Cattegat is connected 

 with the spawning of the eels. 



It is a very rare occurrence to find a migratory eel on the coast in 

 spring, while so called summer eels are often caught with fish-bas- 

 kets and spears. Among the summer eels I have never succeeded in 

 finding a male, much and often as I have searched for it. Among the 

 migratory eels caught last fall in the Gjenner Bay there was a male eel, 

 measuring 51 centimeters [20 inches] in length, the largest which I have 

 ever seen. 



The number of male eels seems to increase with the saltness of the 

 water, so that more male eels are invariably found among those caught 

 on the coast of Zealand than among those caught on the coast of 

 Schleswig-Holsteiu. 



