TOLERANCE OF STRIPED BASS AND AMERICAN SHAD 

 TO CHANGES OF TEMPERATURE AND SALINITY^ 



by 

 Marlin E. Tagatz 



ABSTRACT 



Experiments were conducted to determine the effect of abrupt tempera- 

 ture and salinity changes on adult and juvenile striped bass (Roccus saxatilis) 

 and American shad (Alosa sapidis sima) . Transfers were made at specific 

 temperature and salinity differences over the range 45° to 80° F. and to 

 35 '^'oo . Adult and juvenile striped bass were tolerant to transfers between 

 salt and fresh water at most temperature differences. Adult shad were 

 tolerant to transfers fromfresh to salt water and displayed some tolerance to 

 transfers from salt to fresh water at limited temperature differences. 

 Juvenile shad survived salinity and temperature differences from salt to fresh 

 water, but did not survive these differences from fresh to salt water. 



INTRODUCTION 



Earth-fill barriers have beenproposed 

 for several streams tributary to San Fran- 

 cisco Bay to prevent salt-water intrusion 

 into these rivers which would render them 

 unfit for most industrial, agricultural, and 

 domestic uses. The barriers would cause 

 sharp temperature and salinity differences 

 between the waters divided by the struc- 

 tures. The design of fish-passing facilities 

 for migrating striped bass (Roccus Saxa- 

 tilis) and American shad (Alosa sapidis- 

 sinia) found in this area would in part 

 depend upon the tolerance of these fish to 

 such environmental differences. During 

 1959 and 1960, studies were conducted at 

 the Bureau of Commercial Fisheries Bio- 

 logical Laboratory, Beaufort, N. C., to 

 determine what effect transfers between salt 

 and fresh water, of different temperatures, 

 would have on adult and juvenile striped 

 bass and shad. The majority of adult trans- 

 fers were conducted between "cool-salt" 

 and "warm-fresh" water to conform with 



the temperature pattern relevant to the 

 San Francisco Bay system. Juveniles of 

 these species normally do not migrate from 

 salt to fresh water. In this study, however, 

 juveniles were subjected to this transfer, 

 since the placement of proposed barriers 

 and the migratory habits of these fish in 

 the San Francisco Bay system suggest 

 that movements of this nature could occur. 



LIFE HISTORY 



Striped bass are anadromous members 

 of the sea bass family (Serranidae). Their 

 natural distribution includes the Atlantic 

 coast from the St. Lawrence River, 

 Canada, to the St. Johns River, Fla., 

 and tributaries of the Gulf of Mexico from 

 western Florida to Louisiana. This fish 

 was introduced on the Pacific coast in 1879, 

 and it now occurs from Washington to 

 southern California, Striped bass of both 

 coasts spawn in fresh or virtually fresh 

 water of rivers in the spring and early 

 summer. Most females mature in 4 to 6 



iThis investigation was requested and financed by the U. S. Fish and Wildlife Service, Bureau of Sport Fisheries and Wildlife, 

 Portland, Oregon. 



N'ote;--MarIin E. Tagatz, Fistiery Research Biologist, U. S. Fish and Wildlife Service, Bureau of Commercial Fisheries Biologi- 

 cal Laboratory, Beaufort, North Carolina. 



