The food habits of young shad have been ob- 

 served by many workers. Food was never 

 found in the alimentary canal of young fish 

 less than 10 to 12 days old (Leach, 1925). In 

 about 1 1 days food was present, but the in- 

 testines were seldom densely packed withfood. 

 At 3 wk., an abundance of food was found. Gill 

 (1926), however, found that in about 7 days 

 after hatching, some fish were observed to 

 pursue and feed upon copepods. Leim (1924) 

 noted that in the Shubenacadie River, Canada, 

 larval shad ate planktonic Crustacea and chir- 

 ononnid larvae; the latter predominated until 

 the young fish reached tidal water where 

 copepods became most important. Juveniles 

 took mostly insects and crustaceans (Mitchell, 

 Philip H., and Staff: N. Borodin, R. L.Barney, 

 and Edwin Linton, 1925; Walburg, 1957b). We 

 observed that young shad fed actively from 

 dusk to an hour after sunset and from first 

 daylight to sunrise. 



AGE AND GROWTH 



Various works have described techniques 

 for aging shad. Leim (1924) andGreeley (1937) 

 counted winter rings or annuli on the scales 

 and used the relation of scale size to body 

 length; Borodin (1925) counted transverse 

 grooves; and Barney (1925) read otolith mark- 

 ings. Gating (1953) reported that previous 

 investigators had not established criteria for 

 separating true from false annuli on scales 

 and that these methods therefore gave errone- 

 ous results. Gating proposed a method for 

 reading scales for total age and age at first 

 spawning by counting the transverse grooves 

 to identify true annuli and adding 1 yr. for 

 the scale edge. Age of fish spawning for the 



second time or more was obtained by counting 

 the number of annuli plus the number of spawn- 

 ing marks (year marks but different in form 

 from the prespawning annuli) and adding 1 yr. 

 for the scale edge. LaPointe (1958) validated 

 the annulus as a true year mark on scales of 

 fish spawning for the first time. 



In 1952, 100,000 juvenile shad were marked 

 by pectoral fin-clip in the Connecticut River 

 to validate Cating's method or to establish a 

 correct method for determining age of this 

 species from their scales. Recapture of these 

 marked fish 4, 5, and 6 yr. later validated the 

 use of both annuli and spawning marks for age 

 determination (Judy, 1961). 



In South Atlantic rivers and Chesapeake Bay 

 tributaries, 4- and 5-yr.-old fish make up the 

 bulk of the catch; in the Middle Atlantic rivers, 

 the catch is primarily 4- to 7-yr.-old fish. 



Growth differs between northern and south- 

 ern rivers as well as between sexes. The in- 

 creases of length with age of shad was greater 

 in northern rivers than in southern streams 

 (table 4). Females grow slightly faster than 

 males; hence females are consistently longer 

 than males at all ages (table 5). 



Average weight and length depend on 

 river of origin. Weight of individuals of 

 similar length varies according to condition 

 of fish. 



Shad as heavy as 12 to 14 lb. (pounds) have 

 been reported (McDonald, 1884; Stevenson, 

 1899; and Worth, 1898). Pacific coast fish 

 average a pound or more heavier than those 

 on the Atlamtic coast; many weigh 9 to 12 lb., 

 and occasionally one attains a weight of 14 lb. 

 Fish from less thain 2 to more than 9 lb. have 

 been observed in the commercial catch on the 

 Atlantic coast. Males average between 2 and 

 3 lb. and females between 3 and 4 lb. 



Table 4, — Average fork length of shad, by age and sex, from certain rivers, 

 Atlantic coast of the United States^ 



[Age in years, length in inches and tenths] 



^ Data for: St. Johns, 1957--Walburg (1960a); Neuse, 1953, and Susquehanna, 1952 

 •LaPointe (1958); Connecticut, 1957-58--Unpublished (Beaufort, N. C.) 



