82 



REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



As especial attention has been given by the IT. S. Fish Commission to 

 tbe numbers of eggs laid by tbe various species of sea-fishes and their 

 average magnitude, I will not here pursue the subject further, but 

 merely insert some original measurements by the Commission of eggs 

 of the herring, cod, and mackerel, showing their average size. 



Kinds of fish. 



Herring (Clupea vulgaris) 



Cod (Gadus morrhua) 



Mackerel (Scomber scombrus) 



Eggs. 



Measure- 

 ments. 



Average. 



Inches. 

 1.09 

 1.56 

 2.31 

 1.43 

 1.40 

 1.79 

 0.98 

 0.72 

 1.93 



Inches. 

 .0372 

 .0380 

 . 0366 

 . 0332 

 .0304 

 .0289 

 .0251 

 .0248 

 .0251 



The places of deposit of eggs by fish have already been referred to 

 to some extent under the head of migrations and movements of fish as 

 affected by the reproductive instinct. I shall therefore make only a 

 brief recapitulation of some of the primary divisions. 



The anadromous fish, as already explained, are those that run up from 

 the ocean into the rivers and sometimes lakes in which to deposit their 

 eggs, returning after a short time, and followed by the young after a 

 period sometimes of months and sometimes of one or two years. 



The catadromous fish, of which tbe eel is the only known instance, 

 are those the eggs of which are laid in the sea, the young passing up 

 the rivers and remaining in the fresh waters during the period of imma- 

 ture existence, after which they return to the ocean and probably never 

 again leave it; others, coming from the depths of the ocean, come to 

 the shore to spawn in the summer season, and sometimes even in tbe 

 depth of winter; others, again, discbarge their eggs freely in the sea 

 wherever they happen to be, these eggs, as already explained, float- 

 ing or sinking to the bottom and being adherent or non-adherent.* 



* Prof. Alexander Agassiz has paid special attention to the character and place of 

 deposit of the spawn of fishes of the Atlantic coast, and has furnished me with the 



