112 BULLETIN OF THE BUBEAU OF FISHERIES 



alewife (its body three and one-half times as long as deep), though differing so little 

 in this respect that the two probably intergrade; that the fins are lower (here, again, 

 the difference is so slight as to be hardly dependable); its eyes are smaller; and its 

 back is rather darker blue; but, we repeat, to make certain which fish is in hand 

 open it, glance at the belly Uning, and no doubt will i-emain. 



Size. — The blueback is of about the same size as the ale^^^fe. It grows to a 

 length of about a foot and averages about a half pound in weight when mature. 



Color. — Dark blue above, the sides and belly silvery, with coppery reflections at 

 least in some waters. 



General range. — This is a more southern fish than the alewife, occurring off the 

 Atlantic coast of North America from the Bay of Fundy and Nova Scotia to Florida. 

 It is more mmierous south than north of Cape Cod, and like the alewife spends the 

 greater part of the year in salt water but runs up into brackish and fresh water to 

 spa^vn. 



Occurrence in the Gulf of Maine. — Although Massachusetts fishermen have 

 recognized the existence of two distinct species of alewives at least since 1816, 

 it is difficiilt to arrive at a just idea of the abundance and migrations of this fish 

 in the Gulf, because when "bluebacks" are reported they sometimes turn out to 

 be alewives, while we have heard the latest run of alewives called bluebacks even 

 in streams where the true blueback also occurs. It is certain, however, that schools 

 of the latter are to be expected anj^where between Cape Sable and Cape Cod, for 

 we have seen them freshly caught at Yarmouth on the west coast of Nova Scotia; 

 they are not uncommon in the Bay of Fundy, Huntsman having had specimens 

 from St. John Harbor and Shubenacadie River; they are definitely reported from 

 the St. Croix River, from Eastport, Bucksport, Dennys River, Casco Bay, Small 

 Point, Freeport, and sundry other localities along the coast of Maine, and are taken 

 generally around the shores of Massachusetts Bay, including Cape Cod. Large 

 numbers of bluebacks are sent to market, schools often being seined off the Maine 

 coast outside the islands during summer and early autumn. These are mostly the 

 2-year-old fish, not yet sexually mature, judging from the fact that they are usually 

 reported as very fat. Weirs also make la^ge catches of bluebacks from time to time, 

 and we have seen thousands of them taken from a trap near Gloucester in June. 

 How far offshore the bluebacks may wander is unknown. A few fish were reported 

 under this name from Georges Bank during the investigation of 1913, but whether 

 they were actually bluebacks or alewives is doubtful. It is sufficiently established 

 that the blueback appears in our streams two weeks to a month later than the 

 alewife, and that in streams frequented by both the later runs are bluebacks and 

 the earher ones are alewives. In the Gulf of Maine, at least, it is apparently confined 

 as a spawner to brackish ponds connected with the ocean and to the larger rivers,'* 

 nor does it run far above tide water. 



Habits. — -The spawning habits of the blueback do not differ in any important 

 particular from those of the alewife, except that it does not spawn until the water 



" Along the south shore ot Massaehasetts, tor instance about the head of Buzzards Bay, bluebacks, like alewives, ran up 

 small streams. 



