HISTORY OF THE ICHTHYOLOGY OF NEW BRUNSWICK. 61 



Specimens eighteen inches long are reported by vari- 

 ous authors. At sea, it is said to accompany schools of 

 mackerel, and old fishermen call it the " Mackerel 

 Guide." 



Cliipea aestivalis Mitchill. Blue-Back. Summer 

 Gaspereau. 



In habits and a few points of structure this fish differs 

 from the common alewife, and is now regarded as a dis- 

 tinct though closely allied species. The eyes are smaller, 

 and the fins not so well developed. The peritoneum is 

 black. The average size is much smaller than the spring 

 gaspereau. They enter fresh water late in June and 

 ascend rivers to spawn ; but do not frequent small streams, 

 ponds, and shallow lakes as the ordinary alewife does, 

 seeming to prefer the lower courses of rivers for that pur- 

 pose. Although very fat and delicious as a pan fish, few 

 of them are caught and cured. Their range is co-extensive 

 with that of the larger spring species, which has led many 

 to look upon them as the young of that variety. 



