298 Memoir Sears Foundation for Marine Research 



Figure 73. Alosa sapidissima, larval development, top, immediately after hatching; upper center, third day 

 after hatching; lower center, five days after hatching; bottom, 17 days after hatching. After Leach. 



70 to 125 mm, 34 to 43; in 16 immature fish 190 to 270mm, 48 to 62; and in 

 32 sexually mature examples 465 to 580 mm, 59 to 73. 



The young grow rapidly during their first summer while in fresh water. The 

 total lengths of 769 young taken in the Chesapeake Bay area — mostly from the 

 Potomac River (in 1912) — ranged between 20-69 "^^ during June, 30-74 mm during 

 July, 45-79 mm during August, 50-95 mm during September, 45-99 mm during 

 October, and 60-119 mm during November {^9'- 98)- 



Larger young of 1 50, 1 75, and even 225 mm, at an age of seven months, have been 

 reported. Such fish, in at least one instance, are known to have lived under specially 

 favorable conditions in a pond well supplied with food (at Washington). Furthermore, 

 according to Bean : "Nets set offshore in Gravesend bay [New York] in the fall frequently 

 inclose large quantities of young shad, sometimes a ton and a half at one time, 

 during the migration seaward . . . The fish are usually about 6 to 8 inches long" {8 : 208). 

 One may question whether fish of such a large size, taken in such large quantities, 

 were only six to seven months old. That the young grow faster north of Chesapeake 

 Bay seems unlikely in the light of a statement by Bigelow and Welsh {16 : 1 18) con- 

 cerning this Shad in the Gulf of Maine: "The young shad remain in the rivers until 

 fall when, at a length of 1^/2 to 4^/2 inches (37 to 112 mm) and resembling their parents 



