Shad occasionally are captured in areas out 

 of their general migration. A few adults are 

 caught each year on eel racks in the Delaware 

 River in late summer or fall (Sykes and 

 Lehman, 1957). Others were reported in the 

 lower Hudson River during fall and winter, and 

 in Chesapeake Bay throughout the year. The 

 vast majority offish, however, followed a regu- 

 lar migratory pattern. 



Considerable evidence is available to show 

 that most shad return to their native streanns 

 to spawn. Significant differences in morpho- 

 logical characters indicate discrete spawning 

 populations in rivers along the Atlantic coast 

 (Hildebrand and Schroeder, 1 928; Vladykov and 

 Wallace, 1938; Warfel and Olsen, 1947; Hill, 

 1959; Fischler, 1 959; Nichols, 1 966). The Hud- 

 son River run reached peaks of abundance twice 

 in the past 50 yr., while runs in neighboring 

 streams such as the Connecticut River fluctu- 

 ated independently and in the Delaware River 

 remained low during the same period. Such 

 variations indicated that most of the fish re- 

 turned to their home streams to spawn (Fredin, 

 1954; Talbot, 1954). Significant differences in 

 juvenile body lengths attained at the end of the 

 young shads' stay in fresh water and differ- 

 ences in scale characteristics indicated popu- 

 lations peculiar to each Chesapeake Bay trib- 

 utary (Hammer, 1942"'). 



Tagging and recovery studies revealed even 

 more positive evidence of the return to their 

 native streams. Hollis (1948) released about a 

 thousand tagged juvenile shad at Edenton, N.C., 

 in October 1941. During the spawning migra- 

 tion, 3 to 5 yr. later, three tagged fish were 

 recaptured within a radius of 10 miles from 

 the tagging site, and none was recaptured from 

 any other area. Tagging carried out in Chesa- 

 peake Bay showed that adult shad returned to 

 the sanne spawning areas during successive 

 years (Truitt, 1940). During the spring follow- 

 ing tagging in the Hudson and Connecticut 

 Rivers, no recaptures were made from a 

 spawning ground other than the one where the 

 fish was tagged (Talbot and Sykes, 1958). 

 Similar results were obtained from tagging 

 on the spawning grounds in the York River 

 (Nichols, 1961). 



In 1896 no river on the Atlantic coast ap- 

 peared to be too long for shad to ascend to 

 the headwaters, provided the fish met with 

 nothing to bar their upstream movement. In 

 that year they ascended the St. Johns River 

 about 375 miles, the Altamaha River 300 miles, 

 the Santee River 272 miles, the Neuse River 

 300 miles, and the Susquehanna River 279 

 miles. These distances, however, didnot equal 

 the extreme range of the original limit of the 

 runs (table 1). 



The homing instinct of the Chesapeake Bay shad, 

 Alosa sapidissima (Wilson), as revealed by a study of 

 their scales by Ralph C. Hammer. M.S. degree thesis 

 (typewritten), 1942, University of Maryland, 45 p. 



The difference in the range of shad in rivers 

 between 1896 and I960 is the result of several 

 factors. Construction of insurmountable dams 

 decreased the upstream range in certain 

 rivers, e.g., in the Santee by more than 200 

 miles, in the Cape Fear and Neuse by more 

 than 100 miles each, and in the Susquehanna 

 by more than 50 miles. Runs were completely 

 destroyed in the Housatonic, Kennebec, and 

 Penobscot Rivers. Pollution of the Hudson 

 probably was responsible for decreased up- 

 stream movement. Removal of dams and 

 construction of successful fishways increased 

 the range in certain rivers, e.g., the destruc- 

 tion of Burrows Dam in the Delaware River 

 opened an additional 64 miles, and installation 

 of a fish ramp at Windsor Locks and construc- 

 tion of a fish-lift at South Hadley Dam on the 

 Connecticut River increased the upstream 

 nnigration more than 40 miles (table 1). 



Shad ascend the rivers when the water tem- 

 perature is from 5° to 23° C, the peak move- 

 ment is at 130 to 16° C. (Leach, 1925; Mass- 

 mann and Pacheco, 1957; Talbot, 1961). This 

 upstream migration is for the sole purpose 

 of spawning, but the time of entry into fresh 

 water varies along the coast. Shad appear in 

 the St. Johns River about mid-November, are 

 in greatest abundance from mid-January to 

 mid-February, and the run is completed by 

 the last of March. In Georgia and South Caro- 

 lina rivers, the run begins early in January 

 and ends the last of April. Shad enter the 

 sounds and tributaries of North Carolina and 

 Chesapeake Bay as early as mid-February, 

 and the run usually continues until mid-May. 

 In the Delaware River, the fish are most 

 abundant in early May. They enter the Hudson 

 and Connecticut Rivers by the last of March, 

 and the run usually continues until Jiine. 



The sex ratio is not constant throughout the 

 period of upstream migration. In the early 

 part of the run, males usually dominate. Later, 

 the sexes are about equal or females are 

 more numerous. 



Young shad spend their first summer in 

 rivers and migrate to sea in the autumn. 

 During their river residence, the young fish 

 tend to disperse throughout the area, and 

 juveniles nearest the spawning area are 

 smaller on the average than those below the 

 tidal stretches of the river (Leim, 1924). The 

 findings from our studies were similar to those 

 of Leim on the distribution of young by size 

 gradient. Young collected in the St. Johns 

 River in mid-August averaged 2 in. (inches) 

 fork length (150 specimens) in the upstream 

 spawning areas, and 2.3 in. fork length (100 

 specimens) in the lower river. In the Hudson 

 River, the average fork length of young col- 

 lected in mid-August was 2.5 in. (250 speci- 

 mens) in the upstream spawning area, 2.7 in. 

 (200 specimens) in the central section, and 

 2.8 in. (250 specimens) in the lower river. 

 Young were distributed from the spawning 



