Fishes of the Western North Atlantic 329 



Spawning apparently begins very soon after the fish enter fresh or brackish water. 

 Judging from the size and development of the young and from what is known concern- 

 ing their migration locally, spawning in the Potomac seems to be confined principally 

 to the last half of April and the first half of May. Ripe fish were taken in July (19 15) 

 at Woods Hole, Massachusetts {^6: 123); while most of the females were spent, 

 considerable numbers of each sex were still unripe. 



The spent fish, in the Chesapeake Bay area at least, return to the ocean soon after 

 spawning (^$g: 86). In the Gulf of Maine, "the spent fish, like alewives, return to the 

 sea shortly after spawning. Probably these are the bluebacks taken at Woods Hole 

 and north of Cape Cod in September and October. The winter home of our blue- 

 backs is unknown; probably like their relatives the sea herring, they move out from 

 land and pass the cold season near the bottom" (Bigelow and Welsh, 16: 113). The 

 capture of seven large Bluebacks, up to 375 mm (15 in.) in length, on March 5 

 (1931) about yomilesofFBarnegat, New Jersey (j^: 377), and the acquisition of nine fish 

 by me January 18 (1926) in the market and reported by the dealer to have been taken 

 off Beaufort Inlet, North Carolina, with "sink nets" (often operated in fairly deep 

 water), tend to substantiate the view that they winter near the bottom. The latter 

 fish, one female and eight males, all contained well-developed gonads. Bigelow and 

 Welsh reported that large schools of Bluebacks are often seined off the coast of Maine 

 "outside the islands" during summer and fall and that they consist mostly of "2-year-old 

 fish not yet sexually mature" {16). 



In the Potomac, where the young are abundant below Little Falls throughout 

 the summer, fish 20 mm long were taken there as early as June 17, and none less than 

 30 mm was secured in July. Upon the approach of cool water, October and November 

 in the Chesapeake Bay area, the young leave the fresh waters; they are then about 

 five to six months old, and the greater part of them passes through Chesapeake Bay and 

 out to sea in company with graybacks and shad of a similar age. However, some of them 

 stop to spend their first winter in the deeper parts of the Bay, and a few seem to spend 

 their second winter there. However, no young have been listed as occurring off- 

 shore, from Chesapeake Bay southward. Pearson did list "Pomolobus sp." as having 

 been "observed" in trawl catches off the coast of Virginia and North Carolina {103: 18); 

 whether these fish were young or adults was not stated. 



Food. The food (16: 113) consists of plankton, copepods, pelagic shrimp, and 

 young launce, and no doubt other fish fry. 



Enemies. Undoubtedly the principal enemies of young Bluebacks are the predatory 

 fishes inhabiting the fresh and brackish water they occupy the first several months 

 of life. As they school and move into salt water en route to the sea, marine shore 

 fishes undoubtedly take their toll. Welsh and Breder found that weakfish {Cynoscion 

 regalis) taken at the head of the Acushnet River, Massachusetts, were gorged with 

 the young of this species (JJ2: 159). While the schools migrate from the sea to fresh 

 water, large predatory fishes again must take a toll. Upon arrival in inshore waters 

 and in bays and streams, large numbers are captured by man. 



