The Common Eel 



longitudinal rows, each with about 50 lobules. These spermatic 

 organs can be distinguished at once from the ovaries, not only 

 by their lobular form, but also by their shining glassy appear- 

 ance. 



In 1877 Jacoby made careful investigations of a number of 

 problems concerning the eel, and since then other investigators 

 have worked upon the same problems, until now all essential 

 or important facts in the life history of the eel are well under- 

 stood. These may be briefly stated as follows: 



The common eel spawns in salt water, usually off the 

 mouths of rivers, on mudbanks, to which they go in great 

 numbers at the spawning time, which is in the fall. On these 

 mudbanks the eggs are laid, fertilization takes place, and the 

 young eels develop within two or three months after hatching. At 

 the beginning of the second spring these young find their way 

 to mouths of the rivers, which they ascend in incredible numbers. 

 In these freshwater streams and lakes they remain until of adult 

 size, when they return to the sea for spawning purposes. This 

 seaward migration takes place in the fall, at which time large 

 numbers are caught in traps. During this migration, the eels, 

 like the salmon and the shad, do not take any food. Having 

 once reached the sea, they do not remain close to shore, but go 

 out a distance to deeper water, where the development of the 

 reproductive organs takes place very rapidly. This development 

 is extraordinarily rapid when the immature state, in which the 

 migrating eels are found, is considered; they probably become 

 sexually mature within five or six weeks after reaching the sea. 

 The spawning then takes place, after which both the old males 

 and females die, never returning to fresh water the second 

 time. The very unusual rapid development of their reproductive 

 organs has such an effect upon the systems of the adult eels that 

 they die soon after the act of reproduction. This is the reason 

 that adult eels are never seen migrating up-stream. 



The down-stream movement occurs usually at night, com- 

 mencing soon after sunset, is strongest from midnight to 

 2 o'clock a. m., and ceases an hour or more before sunrise. 



The common eel is remarkably prolific. The number of 

 eggs produced by a single female }2 inches long has been esti- 

 mated at 10,700,000. In the spring of the year thousands of 

 young eels may be seen at the foot of waterfalls and dams, 



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