336 Memoir Sears Foundation for Marine Research 



age. Mature gravid fish often are only 250 mm (10 in.), or even less, and if a length 

 of 200 mm (8 in.) or more is attained at three years of age, it is probable that many 

 become sexually mature and perform their first migration to the spawning grounds 

 when four years old. However, Bigelow and Welsh {16 \ iio) have reasoned that at 

 least some of the fish in the Gulf of Maine area reach maturity at three years of age. 

 This conclusion was reached because the "progeny" of adults used in restocking streams 

 returned in the third year after the streams were restocked. 



Spawning. This species is very prolific; a total of 644 females from the Potomac 

 River yielded an average of 102,800 eggs per fish {lig: 123). The time of spawning 

 varies from some time in March in Chesapeake Bay to late April or May in Maine. 

 They may spawn in running water or in ponds. Ripe fish have been taken many 

 times in the Potomac, near Washington, where the eggs have been found adhering 

 to fish traps and where young occur throughout the summer. Greeley has described 

 their spawning in dense schools in fast water approximately two feet deep over a 

 bottom of coarse stones, some sand, and gravel in the Poestenkill, at Troy, New York 

 (47: 89). Around the Gulf of Maine, however, they spawn more commonly in ponds 

 (including those behind barrier beaches), though probably not so exclusively as Bigelow 

 and Welsh believed {16: 109). 



According to Greeley (.^7: 89): 



The act of spawning is characterized by the whirling of a pair of fish in a close spiral, usually ending as 

 they reach the surface with a splash and separate. The whirling is done rapidly and often only a flash of silver 

 is to be seen. A number of spawning pairs were observed here [presumably the Hudson] by Dr. C. W. Greene 

 and the writer. The sexes of the fish cannot be determined from the appearance of the fish in the water, but it 

 was assumed that the fish seen whirling were mated pairs. It is probable that the male is on the outside of the 

 spiral during the act of spawning and that the rapid circling is adopted for maintenance of contact as the eggs 

 are shed and fertilized. Many eggs were scattered over the bottom and had drifted downstream where they 

 were deposited by the current in slack water areas behind obstructions. The temperatures here May 16(11 A.M.) 

 were: air, 57 degrees; water 52 degrees. 



Migrations and Habitat. This species is strictly anadromous. It has been common 

 knowledge since colonial times that they run 



indifferently up rivers as large as the St. John (New Brunswick), the Merrimac and Potomac, or streams so small 

 one can almost leap across, and only a few inches deep. In large rivers they may run far upstream ... or their 

 journey may be only a few yards, as it is in the artificial cuts that are kept open through barrier beaches to allow 

 the fish access to fresh water ponds behind the latter (75: 103). 



The Graybacks arrive in inshore waters a month or so ahead of the bluebacks and 

 a week or two ahead of the shad. In Chesapeake Bay the first catches are made in late 

 February or early March. In southern New England (Woods Hole, Massachusetts) 

 they arrive sometime during March and are caught through March and April 

 {120: 91). However, they do not reach the rivers of Maine until late April or early 

 May and, as shown by the commercial catches, they are most numerous there during 

 the last half of May {16: 109). 



That the young return to the stream of their birth (the so-called "parent stream 



