Although the difference in the size of fish at various periods 

 of the spring run is a matter of comment among the fishermen, 

 our measurements, confined to a limited period on Monument 

 River, Bournedale, show only a slight difference. 



The variation in the different streams is somewhat more 

 striking. 



The males are smaller and weigh less than the females, and 

 during the breeding season the different contour of the females 

 makes separation easy. In 1,270 measurements the males 

 averaged 10.29 inches compared with 10.88 inches for the 

 females, a difference of 0.59 of an inch in favor of the latter. 

 Approximately 92 per cent of the fish ran as follows: males, 

 from 9.5 to 11 inches; females, 10 to 11.5 inches. 



There is some danger of confusion with the glut herring, which 

 also enters the coastal streams for spawning, but at a slightly 

 later date than the true alewife. According to Smith (4) its 

 spawning takes place nearer the sea. Although superficially the 

 alewife and glut herring resemble each other, the black lining 

 of the body cavity in the latter makes differentiation easy. A 

 close observer will note that externally the alewife is deeper, 



