4o6 Roosevelt Wild Life Annals 



larval life, for the advanced larvae which have been examined have been found 

 to contain no food . . . and this lasts until the\- receive the impulse which 

 will convert them into the young eel stage. . . . During their drift in the 

 Atlantic current the larvae increase from a size of 6 to over 8 cm before they 

 undergo the metamorphosis into the eel condition. It is plain, therefore, that 

 during their oceanic existence they are able to retain their larval condition, and 

 that it is when they are carried into the neighborhood of the coast that the change 

 occurs. It is jiossible. then, that the incentive to the change is the contact with 

 water of lower salinity. . . . When the larvae arrive at about the 500 fathoms 

 line the metamorphosis takes place; but as has been seen, the larval stage is 

 retained in the case of the young larvae entering the Mediterranean. The resulting 

 glass eels, so called on account of their transparency, appear in the North Sea 

 from November to May, mainly from December to February. ... In the 

 rivers of the south of the North Sea the ascent begins in February and continues 

 to June or July. . . . The ascent of the elvers in the rivers is a well-known 

 annual feature. The vast crowds moving upwards in a compact column following 

 each bank of the river, and their persistent efforts to reach the upper parts of the 

 rivers, streams, lakes, and ponds have been often observed and recorded." It has 

 also been observed that the migration is strongest at night, and that it is liable to 

 interruption by lights and even at full moon. (Cox, '16, pp. 115-118). 



Very little indeed is recorded about the migration of American Eels into our 

 streams. Tracy ('10. p. 70) gives the following for Rhode Island: "Migration of 

 young 2 to 3 inches long up Taunton. \\'arren, and Kickamuit rivers takes place 

 from about April 15 to ]\Iay 15." Smith ('13. p. 1 142 ) states: "The migration, 

 coming in late winter or spring, may last for a few days or several weeks in a given 

 stream, and the young, closely skirting the shores, may be in a practically unbroker 

 column during the entire period. All large eels are females, and only females entei 

 con.spicuously into the market supplies in either America or Europe. Any eel 

 over 40 centimeters (16 inches) is almost certain to be female. All eels found in 

 the headwaters of large streams are females. The males remain in the lower 

 courses of rivers and as a rule do not go above the tidewater." Fowler ( 'o(), 

 p. 120) remarks: "In the Dil.iwarc 1 have seen thousands of small eels during 

 July and August wriggling alung the mud and flats as the tide ebbed out. They 

 are about 3 inches in length." (Cf. Fowler. '08, p|). 139-140.) Meek ('16, ]i. 157) 

 further states that "The freshwater life is characterized by a diurnal change from 

 relative quiescence during the day tn relative acti\'ity during the night. ;ui<l the 

 seasonal one from complete or partial hibernation in winter tn the active fredint.' 

 habits of summer." 



WIk'u the I'.els mature in streams, at ;in ;igr between 634 to 8>^ years (cf. A. 

 Mcrl<. '1(1, ]). 15I)). tlK\ begin their journry to the sea. and it is during this journey 

 that so many are caught in traps. Meek ('i(). pp. 135, 156) says: "When the 

 impulse of approaching maturity comes to them, eels undergo a remarkable change. 

 They gradually cease to feed; the under])art of the body becomes clearer and 

 whiter, the dorsal region turns darker. ;nul the eyes -.wv enlarged. Silver eels as 

 they are tlien called, have long been known in lunupe and in America ancl were 

 believed to lie ;i distinct species." 



