From the available data and published literature, it appears 

 that abundance of resident species of decapod crustaceans and 

 fishes from the Santee system will be enhanced by rediversion if 

 riverflow increase is gradual and properly regulated during 

 natural freshets and warm weather periods. Such regulation will 

 insure that salinities do not reach levels below tolerance and that 

 hypertrophic conditions do not occur. On the other hand, the 

 effect of rediversion on transient species such as sciaenid fishes 

 and penaeid shrimps may not be beneficial. A decrease in 

 nursery habitat following rediversion would lower abundance of 

 these species. This is indicated by two aspects of our results: 

 Both biomass and density of the South Santee River, which cur- 

 rently receives less freshwater input, were higher than that of the 

 North Santee River; and both abundance and biomass of domi- 

 nant species appear to be generally lower at the stations furthest 

 upriver. Species diversity will undoubtedly decrease due to 

 decreased utilization of the lower portion of the Santee Rivers 

 by marine stenohaline species. Lower salinity conditions at and 

 near the mouth should deter penetration of the estuary by these 

 species. Whether decreased abundance of marine transients in 

 the vicinity of the upriver stations following rediversion will be 

 offset by more optimum salinity conditions and increased abun- 

 dance nearer the mouths of the rivers is supposition. It appears 

 that rediversion is certain; therefore, it is imperative that careful 

 monitoring of biological and hydrographic conditions occur 

 during and after rediversion in order to ascertain effects on the 

 estuarine biota. 



ACKNOWLEDGMENTS 



We are grateful to all persons who participated in collection 

 of specimens and data in the field and workup of samples at the 

 laboratory. We thank E. B. Joseph and V. G. Burrell, Jr., for 

 their management support and advice during the field study; 

 and Captain V. Taylor of the RV Anita and A. S. Lachicotte for 

 vessel operations. The figures were drafted by K. Swanson and 

 B. Stone; N. Kopacka skillfully created most of the computer 

 programs used in data analysis; W. Coon helped with prepara- 

 tion of tables and proofed the manuscript, and B. Ashby typed 

 the manuscript. We appreciate their patience and organization. 

 The manuscript was improved through reviews by G. Sedberry, 

 R. Van Dolah, C. A. Wenner, C. Bearden, and the two 

 anonymous reviewers. 



The data were collected and automated by support from 

 Coastal Plains Regional Commission (Contract 10340031) as 

 part of the Estuarine Survey Program of the South Carolina 

 Marine Resources Center. First author's support and analysis of 

 the data were funded by NOAA Office of Sea Grant (Grant 

 00140-93027). 



LITERATURE CITED 



ALDERDICE, D. F. 



1972. Factor combinations: Responses of marine poikiJoiherms lo environ- 

 mental factors acting in concert. In O. Kinne (editor). Marine ecology - 

 a comprehensive, integrated treatise on life in oceans and coastal 

 waters. Vol. 1, Part 3, p. 1659-1722. Wiley-lnterscience, N.Y. 



ALEEM, A. A. 



1972. Effect of river outflow management on marine life. Mar. Biol. 

 (Berl.) 15:200-208. 



ANDREWS, J. D. 



1973. Effects of tropical storm Agnes on epifaunal invertebrates in Virginia 

 estuaries. Chesapeake Sci. 14:223-234. 



BARNES. H., and T. B. BAGENAL. 



1951. A statistical study of variability in catch obtained by short repeated 



trawls taken over an inshore ground. J. Mar. Biol. Assoc. U.K. 

 29:649-660. 

 BARRETT, B. B., and M. C. GILLESPIE. 



1973. Primary factors which influence commercial shrimp production in 

 coastal Louisiana. La. Wildl. Fish. Comm., Tech. Bull. 9, 28 p. 



1975. 1975 environmental conditions relative to shrimp production in coastal 

 Louisiana. La. Wildl. Fish. Comm., Tech. Bull. 15, 22 p. 



BISHOP, J. M., and M. H. SHEALY, Jr. 



1977. Biological observations on commercial penaeid shrimps caught by 

 bottom trawl in South Carolina estuaries, February 1973-January 1975. 

 S.C. Mar. Resour. Cent. Tech. Rep. 25, 97 p. 

 BOESCH, D. F. 



1977. A new look at the zonation of benthos along the estuarine gradient. 

 In B. C. Coull (editor), Ecology of marine benthos, p. 245-266. Univ. 

 South Carolina Press, Columbia. 

 BOESCH, D. F., R. J. DIAZ, and R. W. VIRNSTEIN. 



1976. Effects of tropical storm Agnes on soft-bottom macrobenthic com- 

 munities of the James and York estuaries and the lower Chesapeake Bay. 

 Chesapeake Sci. 17:246-259. 



BURRELL, V. G„ Jr. 



1977. Mortalities of oysters and hard clams associated with heavy runoff in 

 the Santee River system, South Carolina in the Spring of 1975. Proc. 

 Natl. Shellfish. Assoc. 67:35-43. 



CALDER, D. R., B. B. BOOTHE, Jr., and M. S. MACLIN. 



1977. A preliminary report on estuarine macrobenthos of the Edisto and 

 Santee River systems, South Carolina. S.C. Mar. Resour. Cent. Tech. 

 Rep. 22, 50 p. 

 CARR, W. E. S., and C. A. ADAMS. 



1973. Food habits of juvenile marine fishes occupying seagrass beds in the 

 estuarine zone near Crystal River, Florida. Trans. Am. Fish. Soc. 

 102:511-540. 

 CHAO, L. N., and J. A. MUSICK. 



1977. Life history, feeding habits, and functional morphology of juvenile 

 sciaenid fishes in the York River estuary, Virginia. Fish. Bull., U.S. 

 75:657-702. 

 CHESAPEAKE BAY RESEARCH COUNCIL. 



1973. Effects of Hurricane Agnes on the environment and organisms of 

 Chesapeake Bay: Early findings and recommendations. Va. Inst. Mar. 

 Sci. Spec. Sci. Rep. Mar. Ocean Eng. 29, 172 p. 



CLIFFORD, H. T., and W. STEPHENSON. 



1975. An introduction to numerical classification. Acad. Press, N.Y., 

 229 p. 

 COPELAND, B. J. 



1966. Effects of decreased river flow on estuarine ecology. J. Water 

 Pollut. Cont. Fed. 38:1831-1839. 

 COPELAND, B. J., and T. J. BECHTEL. 



1974. Some environmental limits of six Gulf coast estuarine organisms. 

 Contrib. Mar. Sci. 18:169-204. 



DOVEL, W. L., J. A. MIHURSKY, and A. J. McERLEAN. 



1969. Life history aspects of the hogchocker, Trinectes maculalus, in the 

 Patu.xent River estuary, Maryland. Chesapeake Sci. 10:104-119. 

 ELLIOTT, J. M. 



1977. Some methods for the statistical analysis of samples of benthic 

 invertebrates. Freshwater Biol. Assoc, Sci. Publ. 25, 160 p. 



GLAISTER, J. P. 



1978. The impact of river discharge on distribution and production of the 

 school prawn Metapenaeus macleayi (Haswell) (Crustacea: Penaeidae) in 

 the Clarence River region, Northern New South Wales. Aust. J. Mar. 

 Freshwater Res. 29:311-323. 



GUNTER, G. 



1938. Seasonal variations in abundance of certain estuarine and marine 

 Fishes in Louisiana, with particular reference to life histories. Ecol. 

 Monogr. 8:313-346. 

 1945. Studies on marine fishes of Texas. Publ. Inst. Mar. Sci. Univ. 



Tex. 1:1-190. 

 1961. Some relations of estuarine organisms to salinity. Limnol. Oceanogr. 

 6:182-190. 

 GUNTER, G., J. Y. CHRISTMAS, and R. KILLEBREW. 



1964. Some relations of salinity to population distributions of motile es- 

 tuarine organisms with special reference to penaeid shrimp. Ecology 

 45:181-185. 

 GUNTER, G., and H. H. HILDEBRAND. 



1951. Destruction of fishes and other organisms on the South Texas coast 

 by the cold wave of January 28-February 3, 1951. Ecology 32:731-736. 

 HAEDRICH, R. L., and S. O. HAEDRICH. 



1974. A seasonal survey of the fishes in the Mystic River, a polluted 



16 



