Table 2. — Age distribution at capture, and number of previous spawnings, 

 for shad from certain rivers, Atlantic coast of the United States-'- 



[In percent] 



Data for: St. Johns, 1958— Walburg (1960a); Ogeechee, 1954~Syk.es (1956); Edisto, 1955~Walburg 

 (1956); Neuse, 1953~Walburg (1957a); James, 1952— Walburg and Sykes (1957); York, 1959— Nichols and 

 Massmann (1963); Potomac, 1952— Walburg and Sykes (1957) ; Delaware, 1944-45-47-52 — Sykes and Lehman 

 (1957); Hudson, 1950-51— Talbot (1954); Connecticut, 1956-59— Walburg (1961). 



2 



Less than 0. 5 percent, 



3 



Determined by counting the number of spawning marks on scales. 



River; in Chesapeake Bay tributaries (James, 

 York, Potomac, and Delaware Rivers) from 

 17 to 27 percent had spa-wned previously; and 

 in the Hudson and Connecticut Rivers, about 

 50 percent had spawned previously. In all 

 streams north of North Carolina, many shad 

 spawn more than once. Fish that have spa-wned 

 for 5 yr. or more have been found in some 

 more northerly streams. 



Spawning in all streams south of Long Island, 

 N.Y., usually is completed by June, and 

 spawning in the Hudson and Connecticut Rivers 

 usually has ended by July. Spa-wning occurs in 

 June and as late as July in Maine and Canada. 

 Usually fish enter the rivers and spawn a 

 few days earlier during warm periods and a 

 few days later when the weather is cold during 

 the spawning migration. After spawning, the 



fish that survive leave the river (at which 

 time they are called "back runners") and most 

 migrate to the Gulf of Maine. 



SPAWNING AND EARLY DEVELOPMENT 



Spawning grounds of shad were located by 

 the relative numbers of eggs collected in 

 plankton nets (fig. 2) and the occurrence of 

 ripe and running females in sport and com- 

 mercial catches. Net samples of eggs indi- 

 cated that spawning areas in rivers are large, 

 extending sometimes 25 to 100 miles inland 

 from the limit of brackish water. In the Con- 

 necticut River, eggs were collected from 

 Haddam Island to Hadley Falls Dam, a dis- 

 tance of more than 100 miles; in the St. Johns 



