THE EEL 



163 



age in years is ascertained by counting the com- 

 plete zones ; the age of the Eel is that of the scale, 

 with the addition of three or four years, one or two 

 occupied in reaching the elver stage, two for the 

 time passed before the young Eel began to form 

 scales ; in the autumn only half a year should be 

 reckoned for the last zone, i.e. for migrating Silver 

 Eels half a year less should be added to the number 

 of zones. 



By applying this method Gemzoe has shown 



FIG. 18. Scale of a Silver Eel showing five annual rings ; the 

 scale 4^, and the Eel from which it was taken ; or 8^ 

 years old (after Gemzoe). 



that the difference in size between the sexes only be- 

 comes apparent when the Eels are about six years old, 

 when the females begin to grow much more strongly 

 than the males. Male Eels were found to assume their 

 breeding dress as a rule after spending five and a half or 

 six and a half years in freshwater, the time varying from 

 four and a half to eight and a half years ; these were 

 from 12 to 20 inches long. Female Silver Eels had 

 usually spent six and a half to eight and a half years in 

 fresh water, and measured from about 14 to 26 inches, 



