= SA Fa a ct SE, ew oo oars ita, Sant nett py eth yetgts np ih Wa Ni “Ae ER TMD AN iy 757 NOAA Technical Report NMFS SSRF- 757 /Zp- eh, A Profile of the Fish and a Decapod Crustacean Community 4, in a South Carolina Estuarine we system Prior to Flow Alteration Elizabeth Lewis Wenner, Malcolm H. Shealy, Jr., and Paul A. Sandifer March 1982 EAN HSON TAR vs i if C 0 199 6 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service NOAA TECHNICAL REPORTS National Marine Fisheries Service, Special Scientific Report—Fisheries The major responsibilities of the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of fishery resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the resources. NMFS is also charged with the development and implementation of policies for managing national fishing grounds, development and enforce- ment of domestic fisheries regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of interna- ional fishery agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs, and mortgage insurance and vessel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The Special Scientific Report—Fisheries series was established in 1949. The series carries reports on scientific investigations that document long-term continuing programs of NMFS, or intensive scientific reports on studies of restricted scope. The reports may deal with applied fishery problems. The series is also used as a medium for the publication-of bibliographies of a specialized scientific nature. NOAA Technical Reports NMFS SSRF are available free in limited numbers to governmental agencies, both Federal and State. They are also available in exchange for other scientific and technical publications in the marine sciences. Individual copies may be obtained from D822, User Services Branch, Environmental Science Information Center, NOAA, Rockville, MD 20852. Recent SSRF’s are: 722. Gulf menhaden, Brevoortia patronus, purse seine fishery: Catch, fishing activity, and age and size composition, 1964-73. By William R. Nicholson. March 1978, iii + 8 p.. 1 fig., 12 tables. 723. Ichthyoplankton composition and plankton volumes trom inland coastal waters of southeastern Alaska, April-November 1972. By Chester R. Mattson and Bruce L. Wing. April 1978, iii + 11 p., | fig., 4 tables. 724. Estimated average daily instantaneous numbers of recreational and com- mercial fishermen and boaters in the St. Andrew Bay system, Florida, and adja- cent coastal waters, 1973. By Doyle F. Sutherland. May 1978, iv + 23 p., 31 figs., 11 tables. 725. Seasonal bottom-water temperature trends in the Gulf of Maine and on Georges Bank, 1963-75. By Clarence W. Davis. May 1978, iv + 17 p., 22 figs., 5 tables. 726. The Gulf of Maine temperature structure between Bar Harbor, Maine, and Yarmouth, Nova Scotia, June 1975-November 1976. By Robert J. Paw- lowski. December 1978, iii + 10 p., 14 figs., 1 table. 727. Expendable bathythermograph observations from the NMFS/MARAD Ship of Opportunity Program for 1975. By Steven K. Cook, Barclay P. Col- lins, and Christine S. Carty. January 1979, iv + 93 p., 2 figs., 13 tables, 54 app. figs. 728. Vertical sections of semimonthly mean temperature on the San Francisco- Honolulu route: From expendable bathythermograph observations, June 1966-December 1974. sy J. F. T. Saur, L. E. Eber, D. R. McLain, and C. E. Dorman. January 1979, iii + 35 p., 4 figs., 1 table. 729. References for the identification of marine invertebrates on the southern Atlantic coast of the United States. By Richard E. Dowds. April 1979, iv + 37 p. 730. Surface circulation in the northwestern Gulf of Mexico as deduced from drift bottles. By Robert F. Temple and John A. Martin. May 1979, iii + 13 p., 8 figs., 4 tables. 731. Annotated bibliography and subject index on the shortnose sturgeon, Aci- penser brevirostrum. By James G. Hoff. April 1979, iii + 16 p. 732. Assessment of the Northwest Atlantic mackerel, Scomber scombrus, stock. By Emory D. Anderson. April 1979, iv + 13 p., 9 figs., 15 tables. 733. Possible management procedures for increasing production of sockeye salmon smolts in the Naknek River system, Bristol Bay, Alaska. By Robert J. Ellis and William J. McNeil. April 1979, iii + 9 p., 4 figs., 11 tables. 734. Escape of king crab, Paralithodes camtschatica, from derelict pots. By William L. High and Donald D. Worlund. May 1979, iii + Il p., 5 figs., 6 tables. 735. History of the fishery and summary statistics of the sockeye salmon, On- corhynchus nerka, runs to the Chignik Lakes, Alaska, 1888-1956. By Michael L. Dahlberg. August 1979, iv + 16 p., 15 figs., 11 tables. 736. A historical and descriptive account of Pacific coast anadromous salmo- mid rearing facilities and a summary of their releases by region, 1960-76. By Roy J. Wahle and Robert Z. Smith. September 1979, iv + 40 p., 15 figs., 25 tables. 737. Movements of pelagic dolphins (Srenel/a spp.) in the eastern tropical Pa- cific as indicated by results of tagging, with summary of tagging operations, 1969-76. By W. F. Perrin, W. E. Evans, and D. B. Holts. September 1979, iii + 14p., 9 figs., 8 tables. 738. Environmental baselines in Long Island Sound, 1972-73. By R.N. Reid, A. B. Frame, and A. F. Draxler. December 1979, iv + 31 p., 40 figs., 6 tables. 739. Bottom-water temperature trends in the Middle Atlantic Bight during spring and autumn, 1964-76. By Clarence W. Davis. December 1972, iii + 13 p.. 10 figs., 9 tables. 740. Food of fifteen northwest Atlantic gadiform fishes. By Richard W. Langton and Ray E. Bowman. February 1980, iv + 23 p., 3 figs., 11 tables. 741. Distribution of gammaridean Amphipoda (Crustacea) in the Middle At- lantic Bight region. By John J. Dickinson, Roland L. Wigley, Richard D. Bre- deur, and Susan Brown-Leger. October 1980, vi + 46 p., 26 figs., 52 tables. 742. Water structure at Ocean Weather Station V, northwestern Pacific Ocean, 1966-71. By D. M. Husby and G. R. Seckel. October 1980, 18 figs., 4 tables. 743. Average density index for walleye pollock, Theragra chalcogramma, in the Bering Sea. By Loh-Lee Low and Ikuo Ikeda. November 1980, iii + 11 p., 3 figs., 9 tables. Vy, NATIONAL Oc € 9 €o S) 41, wy 47MENT oF CO 4 xo Nous NOAA Technical Report NMFS SSRF- 757 A Profile of the Fish and Decapod Crustacean Community in a South Carolina Estuarine System Prior to Flow Alteration Elizabeth Lewis Wenner, Malcolm H. Shealy, Jr., and Paul A. Sandifer March 1982 U.S. DEPARTMENT OF COMMERCE Malcolm Baldrige, Secretary National Oceanic and Atmospheric Administration John V. Byrne, Administrator National Marine Fisheries Service William G. Gordon, Assistant Administrator for Fisheries The National Marine Fisheries Service (NMFS) does not approve, rec- ommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales pro- motion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication. CONTENTS [BeLaTeYeLbtC{ NCO) oes cote Reet ce StS Rae GSU OREN IES EUG EROS. n Ome RO IE cao o one PEE EG aig Og eee MIGMInc oi sone STIGMVENCEIE So solo ob dnine voc Ghec ounce dont hoe shan Sen aUOAGoMoUb md ooo G.cogponoHsedceponudosanoomnge nee IMEI cele lavelisieuevefolarts-s A ctabmo co AA OHO COURS 8 COO CcIOe ao Hod c cidido peo Uc uumUooD Ue oonueo dado ID ey(cfa} ll etnlo) ni mean ode She ea eREGIN aS Denote ce ooo ine acon catinis oc bnonic odes ie pe Oa boa Den a IDEVEL ETE IN ls Ss eats iaitatd o alterna Gah OS cube he meet Seeds oon hac oe neucies anima Sooueminoe anon 1 RVETUT US center cea pret r rcito. PERO cS SIGE OPO ICs Ais NGL ERENT ae AL I A eee Ge aa es brea era ain Hea ele FAY ArOpTaphicparamelersis kaa verry susie ce cues esses tees eapetc aie estes ale alae Vaenelai eile! ofuils sulewetrctearale lonehaliegs cone eeeye ede vetsta) Gommurmnityicompositioniandiciversityimeeeencersc euste te sie cee Rial caro Uc Ue Memeo etncrs 6 oma cides. o Caen cke Ninthe batcd octane mors Abundance of A) Penaeus aztecus and B) Callinectes sapidus. Ratios over the bars indicate number of collec- tions where shrimp were captured to total number of collections at astation ............ 0.0 eee eens eee eee Tables Total number and total weight of fishes collected from 1975 and 1976 in estuaries of the North and South Santee Rivers, S.C. Species are listed in order of abundance, and data are pooled from the 2-yr sampling jokes 20010 bree rite cairn eer aneet ONelS/ Cone eras <8 Ci nae ear aE NS PN a pn eR A rere Gils nec ead Total number and total weight of decapod Crustacea collected from 1975 and 1976 in the North and South Santee Rivers. Species are listed in order of abundance and data are pooled over the 2-yr sampling period ..... Correlation between In (n + 1) transformed values of number of species and number of individuals of fishes andidecapodsiinirelationitojenvironmentalifactotsieachns cise eee ne ee ee Eeeesteicene Groups formed from cluster analysis of species of fishes and decapod Crustacea collected in the North and SouthSanteesRiversitromul 9/SiandvO7 Gua cegaessieeve ete eatiee ire eine eee eee rece trs Estimates of density and number of individuals/ha for fishes caught by trawls from estuaries along the Gulf and easicoastsiofitheiWnitediStates; pay spyeiey sete eee ncis inh ote) sak APS rE ITs EIR Pol SO aR EI Re CL GTC ISTO ili 10 11 12 13 ar PGS SS He =) i aD Y, LTE ey a Api nadie ag) oy A Profile of the Fish and Decapod Crustacean Community in a South Carolina Estuarine System Prior to Flow Alteration! ELIZABETH LEWIS WENNER, MALCOLM H. SHEALY, JR., and PAUL A. SANDIFER? ABSTRACT The seasonal distribution and abundance of fishes and decapod Crustacea collected by 6 m otter trawl from the North and South Santee Rivers, South Carolina, were examined over a 2-year sampling period. Species richness was greatest during summer and at stations located in proximity to the river mouths. Although species richness was found to be related to salinity, temperature, depth, and dissolved oxygen, it was most noticeably affected by a spring freshet which considerably lowered richness and abundance. Eleven species accounted for 93% of the number and ~ 70% of the total fish biomass taken in both rivers: Micropogonias undulatus, Anchoa mitchilli, Bairdiella chrysoura, Stellifer lanceolatus, Ictalurus catus, Cynoscion regalis, Dorosoma petenense, Leiostomus xanthurus, Trinectes maculatus, Brevoortia tyrannus, and Symphurus plagiusa. White shrimp, Penaeus setiferus; brown shrimp, P. aztecus; and blue crabs, Callinectes sapidus, comprised over 96% by number and weight of the decapod fauna collected in both rivers. Dominant fishes were present in fairly equal abundance throughout the year and utilized the Santee system as either a residential or nursery area, while P. setiferus and P, aztecus were more seasonal in their pattern of appearance and abundance. Length-frequency analysis showed the Santee system fish fauna to be composed mostly of juvenile specimens. Their presence throughout the year indicated that the Santee is a temporally stable and relatively nonstressed system and an important nursery area. The predominance of juveniles accounted for lower biomass (kg/ha) of fishes in the Santee system compared to values for other estuaries along the Atlantic coast of the United States. The continued importance of juvenile fishes and shrimp in the Santee system is questionable in view of salinity changes in the nursery habitat following proposed river rediversion. INTRODUCTION A number of published accounts are available on community ecology of estuarine fauna along the northeastern and south- eastern coasts of the United States. Despite this, few com- prehensive studies exist on distributional patterns and faunal composition of estuarine megafauna, such as fishes and decapods, from a system which has experienced as many manipulations as the Santee River, S.C. The drainage basin of the Santee encompasses 41,000 km? in North and South Carolina. The Santee was the fourth largest river on the U.S. east coast prior to diversion of most of its flow into the Cooper River in 1942. Diversion not only lowered the annual mean discharge from 525 m?/s to 74 m’/s but also caused severe shoal- ing in Charleston Harbor at the mouth of the Cooper River (Kjerfve and Greer 1978). Changes in the amount of freshwater flow completely altered the supply and deposition of sediments, erosion patterns, salinity regime, flooding characteristics, and floral and faunal communities (Kjerfve 1976). After diversion, the salinity in the Santee distributaries, the North and South Santee Rivers, increased sharply. In addition, large quantities of fine-grained suspended sediments were transported into the Cooper River and, eventually, into Charleston Harbor. The costly necessity to dredge Charleston Harbor continuously prompted a rediversion project begun in 1975 whereby 80% of the Cooper River flow eventually will be directed back into the Santee system (Kjerfve 1976). Upon projected completion of Contribution No. 139 from the South Carolina Marine Resources Center. *Marine Resources Research Institute, P.O. Box 12559, Charleston, SC 29412. rediversion on the North and South Santee Rivers is purely 428 m?/s (Kjerfve and Greer 1978). Although the impact of rediversion on the North and South Santee Rivers is purely speculative, it is likely to reduce the net salinity in the Santee system and increase amounts of fine-grained suspended sediments. Kjerfve and Greer (1978) cautioned that these com- bined changes may ultimately end the economically important American oyster, Crassostrea virginica, and hard clam, Mercenaria mercenaria, fisheries flourishing at present in this river. The effect of rediversion on fishes and decapod Crustacea also may be substantial. Shealy and Bishop (1979) suggested that population changes in penaeid shrimp may occur, and the extent of nursery areas may be affected. Fishes such as Jctalurus catus, I, punctatus, Morone saxatilis, and Anguilla rostrata, which are frequently encountered in lower salinity regions of estuaries, may increase in abundance in the Santee system; however, the effect on most species, such as the euryhaline sciaenid fishes which are numerically dominant in South Carolina estuaries (Shealy et al. 1974), cannot be predicted. The present study examines quantitative annual and seasonal variability, diversity, and species assemblages of fishes and decapod Crustacea found in the channel of the lower North and South Santee Rivers. Our primary consideration is to describe the megafaunal community as it currently exists and to relate distributional patterns to abiotic factors which may influence the community after rediversion. STUDY AREA All sampling stations were located within the Santee River system (Fig. 1). The Santee River provides the major headwaters SCALE = 1:100,000 = FS : NN MURPHY ISLAND Figure 1.—Station locations in North and South Santee Rivers, S.C. supplying Lakes Marion and Moultrie. About 23 km from the ocean, the Santee River bifurcates to form the North and South Santee Rivers. The Santee system has been classified by Kjerfve and Greer (1978) as a partially mixed estuary with weak-to-moderate salinity Stratification and gravitational circulation. However, this classification is variable due to tidal fluctuations as well as varia- tions in saltwater intrusion and freshwater discharge (Cummings 1970’; Stephens et al. 1975; Kjerfve 1976; Nelson 1976; Burrell 1977; Calder et al. 1977). The South Santee River receives less freshwater drainage, with the result that saltwater intrusion is greater than in the North Santee River. The two distributaries differ somewhat with regard to ba- thymetry since the North Santee River is slightly deeper than the South Santee River. Substrate in both rivers is very similar, being predominately coarse to fine-grained sand and shell of Oceanic origin at the mouths, and hard mud and sand mix in the intermediate reaches of the estuary, replaced by fine-grained sand of inland origin in the upper estuary (Calder et al. 1977). Dissolved oxygen values fluctuate seasonally, being usually 9-14 mg/liter in winter and >4 mg/liter in summer (Cummings footnote 3; Nelson 1976; Mathews’). MATERIALS AND METHODS Data Collection We sampled eight stations which were located in the channel at 1, 4, 7, and 11 river miles from the mouths of the North and ‘Cummings, T.R. 1970. A reconnaissance of the Santee River estuary, South Carolina. A report prepared by United States Geological Survey, Water Resources Division, Columbia, S.C., 96 p. “T. Mathews, Assistant Marine Scientist, South Carolina Marine Resources Research Institute, Charleston, SC 29412, pers. commun. December 1979. South Santee Rivers (Fig. 1). Hereafter, we will refer to these stations as NSO1, NS04, NSO7, and NS11 in the North Santee River and SSO1, SS04, SSO7, and SS11 in the South Santee River. Stations were sampled monthly over a 2-yr period from January 1975 through December 1976, with the following excep- uions which were not included in our analysis: SS11 was not sampled in 1975; NSI1 was sampled with a 5 m (16 ft) trawl in May and July 1975; and NSO7 was not successfully trawled in May 1975. All collections were made with a 6 m (12 ft) semiballoon otter trawl with 8 m headrope, composed of 2.5 cm (1 in) stretch mesh throughout. A complete description of the trawl is given by Shealy et al. (1974). Twenty-minute tows were made against floodtide during daylight hours at a speed of 1.3 m/s (2.5 kn), which resulted in a coverage of 1.5 + 0.4 km during a tow. Bottom-water samples were collected with 6 liter capacity Van Dorn bottles 0.3 m above the bottom at each station prior to trawling. Water temperature was read from stem thermometers mounted within the Van Dorn bottles. Salinity was measured in the laboratory with a Beckman RS7B induction salinometer. Dissolved oxygen was determined by the Winkler-Carpenter method (Strickland and Parsons 1968). Turbidity was deter- mined with a Hach Model 2100A turbidimeter. Specimens were either processed in the field or preserved in 10% Formalin and returned to the laboratory for identification, measuring, and weighing. All specimens were weighed to the nearest 0.1 g and counted. We also recorded measurements (total length for fishes, carapace width for crabs, and total length for shrimps) for all species numbering <50 specimens per tow. At stations where the trawl caught larger numbers of organisms, we sub- sampled the catch as follows: If =>50 to <250 individuals were collected, then a minimum of 50 randomly selected specimens were measured; if >250 to <500 individuals were caught, then 20% of the catch was measured; when >500 were caught, 10% of the catch was measured. Data Analysis Cluster analysis was used to define assemblages of fishes and decapod crustaceans and to determine degree of similarity among stations. Prior to cluster analysis, data were loga- rithmically transformed by log,, (x + 1), where x is number of individuals for a given species. We reduced data by elimination of species which occurred in fewer than three collections during a sampling period and by elimination of collections which con- tained only one species. The methods of cluster analysis used are described in detail by Boesch (1977). The Bray-Curtis coefficient (Clifford and Stephenson 1975) was used to compute similarity values. Sym- metrical similarity matrices were computed for both the North and South Santee Rivers on data from the 2-yr sampling period with collections as entities and species as attributes (normal analysis), and with species as entities and sites as attributes (in- verse analysis). Entities were classified into related groups by using flexible sorting (Lance and Williams 1967) with 6 = —0.25. Two separate dendrograms were generated for each river: A dendrogram which indicated association of all collections during the 2-yr sampling period based on their faunal content and a dendrogram which indicated association of all species from the collections made during the 2-yr sampling period. We used postclustering techniques of nodal analysis (Williams and Lambert 1961; Lambert and Williams 1962) to examine species and station coincidences. Nodal analysis diagrams were made by using patterns of constancy (a measure of how consistently a species is found in a site group) and fidelity (a measure of how restricted a species is to a site group). An index of abundance (Musick and McEachran 1972; Elliott 1977) was used to compare numbers and weights of selected dominant species and is expressed as: n 1 Index of Abundance = =p logio (x + 1), ear where x = number or weight of individuals of a given species and m = number of collections in a chosen time frame. We determined biomass and density estimates for fishes and decapods from computations of area swept for trawl gears. Estimates of area swept (a) were determined by the following equation given by Roe (1969): K x M x (0.6 AH) 7 ~ 0,000 m2/ha where K is speed in meters per hour, M is time in hours fished, and H is headrope length in meters (Klima‘’). Roe (1969) as- sumed an effective swath of about 60% of the headrope length as established by Wathne (1959). The area swept by our 6 m Otter trawl was estimated to be 0.72 ha/tow based on the method described by Roe (1969). *Klima, E. F. 1976. A review of the fishery resources in the western central Atlantic. West. Cent. Atl. Fish. Comm. Publ. 3, 77 p. RESULTS Hydrographic Parameters Bottomwater temperatures were very similar between rivers and among stations. Temperatures were lowest in both the North and South Santee Rivers during February and March 1975 and January and February 1976. In the North Santee River, temperatures gradually increased from April to reach a peak in either August (1976) or September (1975). The warmest month in the South Santee River during both years of sampling was August. Based on temperature over the 2-yr sampling period, winter encompassed January, February, and March; spring, April, May, and June; summer, July, August, and September; and fall, October, November, and December. Salinities were extremely variable both seasonally and among stations. Freshwater outflow increased in the Santee watershed from 14.2 m?/s to an average of 679.3 m?/s between mid-March and mid-April 1975 and to 238.5 m?/s from mid-May until late June 1975 (Burrell 1977). These freshets considerably lowered salinities at stations in both rivers. Salinities were also variable in 1976 but the extreme fluctuations caused by freshwater outflow were not as evident as in 1975. Except during periods of high runoff when freshwater was found throughout the system, salinity decreased from stations located at the river mouth to those located upstream. Salinities at stations SSO1 and NSO1 ranged from 0.2 to 32.9%,,, which characterized these stations as limnetic-euhaline by the Venice System (Symposium on the Classification of Brackish Waters 1958). Stations SS04 and NSO4 were limnetic-polyhaline (0.1-26%,,), while SSO7 and NSO7 were limnetic-mesohaline (0.1-15.9Y,,). Salinities at NS11 and SS11 ranged from <0.1 to 1.4%, and were within the limnetic-oligohaline salinity regime. Community Composition and Diversity Eighty species of fishes were collected from the South Santee River and 64 species from the North Santee River during the 1975-76 sampling period (Table 1). Eleven species accounted for 93% of the total number of specimens and 70% of the total fish biomass taken in both rivers: Atlantic croaker, Micropogonias undulatus; bay anchovy, Anchoa mitchilli; silver perch, Bair- diella chrysoura; star drum, Stellifer lanceolatus; white catfish, Ictalurus catus; weakfish, Cynoscion regalis; threadfin shad, Dorosoma petenense; spot, Leiostomus xanthurus; hogchocker, Trinectes maculatus; Atlantic menhaden, Brevoortia tyrannus; and blackcheek tonguefish, Symphurus plagiusa. In both rivers, M. undulatus was the most abundant species collected. With regard to biomass, however, M. undulatus was outranked by J. catus in the North Santee River and Bairdiella chrysoura in the South Santee River. The decapod crustaceans were represented by 22 species in the North Santee River and 18 species in the South Santee River. Although fewer species of decapods than fish were collected, the decapods dominated in terms of total number of individuals captured (Table 2). The numerical dominance of the decapods was due to extremely large catches of the white shrimp, Penaeus setiferus, especially in the South Santee River. This species was by far the most abundant decapod collected in both rivers and also dominated other decapods in terms of biomass. Penaeus setiferus, together with the brown shrimp, P. azfecus, and the blue crab, Callinectes sapidus, comprised over 96% by number and weight of the total decapod fauna collected in both rivers. Table 1.—Total number and total weight (kg) of fishes collected from 1975 and 1976 in estuaries of the North and South Santee Rivers, S.C. Species are listed in order of abun- dance, and data are pooled for the 2-yr sampling period. Total Percent of Total Percent Total Percent of Total Percent Species no. total catch weight —_ weight Species no. total catch weight weight North Santee River: South Santee River: Micropogonias undulatus 3,535 23.68 20.282 10.12 Micropogonias undulatus 4,385 31.72 23.815 13.90 Trinectes maculatus 3,233 21.66 15.251 7.61 Anchoa mitchilli 2,944 21.29 4.259 2.49 Ictalurus catus 1,975 13.23 58.429 29.16 Bairdiella chrysoura 2,187 15.82 33.547 19.58 Anchoa mitchilli 1,502 10.06 2.895 1.44 Stellifer lanceolatus 636 4.60 3.419 2.00 Brevoortia tyrannus 824 5.52 13.600 6.79 Ictalurus catus 625 4.52 25.443 14.85 Stellifer lanceolatus 766 5.13 3.651 1.82 Cynoscion regalis 595 4.30 2.478 1.45 Cynoscion regalis 555 3.72 2.528 1.26 Dorosoma petenense 400 2.89 2.102 1.23 Bairdiella chrysoura 531 3.56 8.621 4.30 Leiostomus xanthurus 348 2:52) 9.100 §.31 Dorosoma petenense 467 3.13 1.831 0.91 Trinectes maculatus 304 2.20 1.657 0.97 Symphurus plagiusa 418 2.80 5.387 2.69 Brevoortia tyrannus 291 2.10 11.039 6.44 Leiostomus xanthurus 207 1.39 9.135 4.56 Symphurus plagiusa 220 1.59 2.193 1.28 Ictalurus punctatus 150 1.00 3.623 1.81 Paralichthys lethostigma 155 1.12 13.274 7.75 Ictalurus furcatus 142 0.95 7.785 3.88 Opsanus tau 85 0.61 7 470 4.36 Paralichthys lethostigma 131 0.88 15.664 7.82 Hypsoblennius ionthas 60 0.43 0.187 0.11 Menticirrhus americanus 57 0.38 0.531 0.26 Hypsoblennius hentzi 58 0.42 0.246 0.14 Urophycis regia 50 0.33 0.339 0.17 Paralichthys dentatus 42 0.30 1.502 0.88 Arius felis 49 0.33 1.024 0.51 Menticirrhus americanus 34 0.25 0.284 0.17 Opsanus tau 29 0.19 1.502 0.75 Cynoscion nebulosus 30 0.22 1.033 0.60 Paralichthys dentatus 25 0.17 0.840 0.42 Centropristis striata 29 0.21 0.627 0.37 Etropus crossotus 25 0.17 0.075 0.04 Urophycis regia 28 0.20 0.351 0.20 Anguilla rostrata 19 0.13 2.301 115 Peprilus triacanthus 26 0.19 0.203 0.12 Alosa sapidissima 17 0.11 0.114 0.06 Gobiesox strumosus 25 0.18 0.076 0.04 Urophycis floridana 17 0.11 0.582 0.29 Peprilus alepidotus 23 0.17 0.130 0.08 Cyprinus carpio 16 0.11 2.793 1539, Chloroscombrus chrysurus 21 0.15 0.196 0.11 Cynoscion nebulosus 13 0.09 0.327 0.16 Alosa aestivalis 20 0.14 0.057 0.03 Chloroscombrus chrysurus 13 0.09 0.028 0.01 Alosa sapidissima 19 0.14 0.149 0.09 Alosa aestivalis 12 0.08 0.295 0.15 Etropus crossotus 19 0.14 0.206 0.12 Dasyatis sabina 12 0.08 10.851 5.41 Citharichthys spilopterus 18 0.13 0.118 0.07 Gobiesox strumosus 11 0.07 0.047 0.02 Ictalurus furcatus 17 0.12 0.632 0.37 Prionotus tribulus 11 0.07 0.022 0.01 Archosargus probatocephalus 17 0.12 3.861 2.25 Peprilus triacanthus 9 0.06 0.045 0.02 Urophycis floridana 16 0.12 0.432 0.25 Pomatomus saltatrix 9 0.06 0.220 0.11 Lagodon rhomboides 13 0.09 0.405 0.24 Morone saxatilis 8 0.05 0.070 0.03 Dasyatis sabina 9 0.07 7.515 4.39 Peprilus alepidotus 8 0.05 0.045 0.02 Lepisosteus osseus 8 0.06 8.075 4.71 Astroscopus y-graecum 7 0.05 0.067 0.03 Pomatomus saltatrix 8 0.06 0.285 0.17 Anchoa hepsetus 7 0.05 0.055 0.03 Prionotus tribulus 8 0.06 0.011 0.01 Hypsoblennius hentzi 6 0.04 0.045 0.02 Selene vomer tf 0.05 0.046 0.03 Centropristis striata 6 0.04 0.228 0.11 Anchoa hepsetus 7 0.05 0.057 0.03 Lagodon rhomboides 6 0.04 0.044 0.02 Ancylopsetta quadrocellata 6 0.04 0.382 0.22 Mugil cephalus 5 0.03 0.199 0.10 Prionotus evolans 6 0.04 0.009 0.01 Ictalurus platycephalus 5 0.03 0.717 0.36 Ictalurus punctatus 6 0.04 0.227 0.13 Ancylopsetta quadrocellata 4 0.03 0.037 0.02 Opisthonema oglinum 5 0.04 0.014 0.1 Dorosoma cepedianum 4 0.03 1.243 0.62 Caranx hippos 4 0.03 0.008 <0.01 Ophidion marginatum 4 0.03 0.149 0.07 Centropristis philadelphica 4 0.03 0.172 0.10 Lepisosteus osseus 3 0.02 5.213 2.60 Ophidion marginatum 4 0.03 0.166 0.10 Selene vomer 3 0.02 0.013 0.01 Lutjanus griseus 4 0.03 0.041 0.02 Membras martinica 2 0.01 0.005 <0.01 Morone saxatilis 3 0.02 0.054 0.03 Eucinostomus argenteus 2 0.01 0.021 0.01 Dorosoma cepedianum 3 0.02 0.143 0.08 Citharichthys spilopterus 2 0.01 0.005 <0.01 Arius felis 3 0.02 0.418 0.24 Gobionellus hastatus 2 0.01 0.093 0.05 Eucinostomus sp. 5 0.02 0.042 0.02 Hypsoblennius ionthas 2 0.01 0.007 <0.01 Prionotus scitulus 3 0.02 0.007. <0.01 Chaetodipterus faber 1 0.01 0.223 0.11 >Scomberomorus maculatus 2 0.01 0.043 0.03 Prionotus scitulus 1 0.01 0.002 <0.01 Eleotris pisonis 2 0.01 0.024 0.01 Archosargus probatocephalus 1 0.01 0.338 0.17 Astroscopus y-graecum 2 0.01 0.011 0.01 Morone americana 1 0.01 0.484 0.24 Bagre marinus 2 0.01 0.158 0.09 Centropristis philadelphica 1 0.01 0.144 0.07 Orthopristis chrysoptera 2 0.01 0.112 0.07 Bagre marinus 1 0.01 0.007 <0.01 Chaetodipterus faber 2 0.01 0.176 0.10 Acipenser oxyrhynchus 1 0.01 0.300 0.15 Mugil cephalus 1 0.01 0.100 0.06 Prionotus sp. 1 0.01 0.001 <0.01 Sciaenops ocellata 1 0.01 0.002. <0.01 Gobionellus shufeldti 1 0.01 0.001 <0.01 Larimus fasciatus 1 0.01 0.001 <0.01 Eucinostomus sp. 1 0.01 0.008 <0.01 Eucinostomus argenteus 1 0.01 0.002. <0.01 Scophthalmus aquosus 1 0.01 0.002 <0.01 Morone americana 1 0.01 0.338 0.20 Perca flavescens 1 0.01 0.017 0.01 Syngnathus louisianae 1 0.01 0.008 <0.01 Chilomycterus schoepfi 1 0.01 0.002 <0.01 Menidia menidia 1 0.01 0.002 <0.01 Total 14,929 200.403 Membras martinica 1 0.01 0.004 =< 0.01 SsSrrongylura marina 1 0.01 0.075 0.04 Trachinotus falcatus 1 0.01 0.008 <0.01 Trachinotus carolinus 1 0.01 0.005 <0.01 Urophycis earlli 1 0.01 0.001 <0.01 Brevoortia smithi 1 0.01 0.268 0.16 Table 1.—Continued. Total Percent of Total Percent Species no. total catch weight weight South Santee River.—Cont. Anguilla rostrata 1 0.01 0.150 0.09 Mugil curema 1 0.01 0.040 0.02 Gobionellus hastatus 1 0.01 0.009 0.01 Prionotus carolinus 1 0.01 0.001 <0.01 Prionotus sp. 1 0.01 0.002 <0.01 Cyprinus carpio 1 0.01 1.562 0.91 Gobionellus shufeldti 1 0.01 0.002 <0.01 Diapterus olisthostomus 1 0.01 0.022 0.01 Chilomycterus schoepfi 1 0.01 0.085 0.05 Monacanthus hispidus 1 0.01 0.003 <0.01 Total 13,826 171.372 The total number of species of fishes and decapods varied over the 2-yr sampling period with the greatest number oc- curring in summer in both rivers (Fig. 2). Fewest species were collected during spring of 1975 when freshwater input and river- flow drastically increased. The dramatic drop in number of species was most noticeable at stations located upriver (NSO7, NS11, and SSO7). The total number of species captured was much lower during this time period than in spring of 1976 when no freshet occurred. During the 2-yr sampling period, more species were collected at stations nearest the mouths of both rivers. The number of individual fish and decapod crustaceans, expressed in logarithms, showed patterns similar to the number of species when plotted over time (Fig. 2). In both rivers, numbers of individuals were greater during 1975, with peaks oc- curring in summer. The number of species and number of individuals were com- pared to environmental factors such as bottom temperature, salinity, oxygen, turbidity, and depth using Pearson’s product- moment correlation coefficient (Table 3). Based on these analyses, we found the number of species in the North Santee River to be significantly associated with bottom temperature and salinity in 1975 and with salinity and depth in 1976. In the South Santee River, the number of species was significantly associated with salinity during both years. In the North Santee system, the number of individuals was positively correlated with bottom temperature in 1975, but there were no significant associations detected between number of in- dividuals and environmental factors in 1976 (Table 3). The number of individuals captured in the South Santee system was positively correlated with bottom temperature and negatively correlated with oxygen in 1975 and 1976. A positive correlation with depth was found also in 1976. Normal cluster analysis revealed that no strong differentiation of collections existed by river mile. Rather, collections made in the limnetic-euhaline zone were grouped with those from the limnetic-oligohaline zone indicating little stratification of the fauna according to salinity regime. In addition, an examination of the allocation of collections according to station and month indicated that association of the collections was not related to time of year. Based on similarity of faunal composition, we discerned three primary station groups by cluster analysis of data from the North Santee River: 1) a group in which collec- tions at station NSO1, NS04, and NSO7 were represented by nearly equal numbers of collections; 2) a group in which collec- tions at station NSO] predominated; and 3) a group which was most distinct from the other groups and was dominated by col- lections made at station NS11. Two major groupings of stations were indicated by cluster analysis for the South Santee River: 1) a group consisting mostly of collections from stations SSO1 and SS04, and 2) a group consisting predominantly of collections from stations SSO7 and SS11. Table 2.—Total number and total weight (kg) of decapod Crustacea collected from 1975 and 1976 in the North and South Santee Rivers. Species are listed in order of abun- dance and data are pooled over the 2-yr sampling period. Total Percent of Total Percent Species no. total catch weight weight North Santee River: Penaeus setiferus 34,998 90.08 121.703 48.38 Penaeus aztecus 1,556 4.00 13.393 5.32 Callinectes sapidus 1,318 3.39 114.709 45.60 Palaemonetes vulgaris 510 1.31 0.228 0.09 Palaemonetes pugio 255 0.66 0.125 0.05 Penaeus duorarum 95 0.24 1.036 0.41 Panopeus herbstii 23 0.06 0.085 0.03 Portunus gibbesii 19 0.05 0.016 0.01 Callinectes similis 18 0.05 0.161 0.06 Trachypenaeus constrictus 18 0.05 0.019 0.01 Rhithropanopeus harrisii 17 0.04 0.013 0.01 Clibanarius vittatus 13 0.03 0.024 0.01 Portunus spinimanus 5 0.01 0.008 <0.01 Macrobrachium ohione 3 0.01 0.028 0.01 Xiphopenaeus kroyeri 2 0.01 0.008 = <0.01 Panopeus occidentalis 2 0.01 0.002 <0.01 Panopeus sp. 1 <0.01 0.001 <0.01 Alpheus heterochaelis 1 <0.01 0.001 <0.01 Total 38,854 251.556 ‘Field identification. *Specimen damaged and unidentifiable, not included in analyses. Total Percent of Total Percent Species no. total catch weight weight South Santee River: ' Penaeus setiferus 10,431 78.80 44.333 44.98 Penaeus aztecus 1,726 13.04 10.242 10.39 Callinectes sapidus 568 4.29 42.763 43.39 Macrobrachium ohione 120 0.91 0.414 0.42 Palaemonetes pugio 90 0.68 0.047 0.05 Palaemonetes vulgaris 89 0.67 0.052 0.05 Trachypenaeus constrictus 83 0.63 0.071 0.07 Callinectes similis 31 0.23 0.184 0.19 Penaeus duorarum 17 0.13 0.077 0.08 Clibanarius vittatus 16 0.12 0.024 0.02 Pagurus longicarpus 12 0.09 0.006 0.01 Xiphopenaeus kroyeri 12 0.09 0.030 0.03 Rhithropanopeus harrisii 10 0.08 0.134 0.14 Portunus spinimanus 7 0.05 0.104 0.11 Callinectes similis or ornatus' 7 0.05 0.018 0.02 Callinectes ornatus 5 0.04 0.031 0.03 Panopeus herbstii 4 0.03 0.006 0.01 Portunus gibbesti 3 0.02 0.007 0.01 Alpheus heterochaelis 2 0.02 0.002 <0.01 Acetes americanus 1 0.01 0.001 <0.01 Ovalipes ocellatus 1 0.01 0.002 <0.01 Eurypanopeus depressus 1 0.01 0.001 <0.01 Xanthidae? 1 0.01 0.008 0.01 Total 13,237 98.557 NO. SPECIES NO. SPECIES re4 No. Species ---- Log. No. Individuals LOG. NO. INDIVIDUALS Figure 2.—Monthly fluctuations in number of species and number of individuals (log transformed) of fishes and decapod crustaceans at sampling sites in the North and South Santee Rivers, 1975-76. Table 3.—Correlation between In (n + 1) transformed values of number of species and number of individuals of fishes and decapods in relation to environmental factors. r = Pearson product- moment correlation coefficient; 7 = number of observations. 1975 1976 North Santee South Santee North Santee South Santee Environmental factor r n r n r n r n Number of species Number of species Bottom temperature (°C) 0.4270* 45 0.1646 36 —0.0225 48 -—0.0769 48 Salinity (%,,) 0.3984* 45 0.4185* 36 0.5437* 48 0.5929* 48 Oxygen (mg/liter) —0.1575 45 -—0.0457 36 -—0.0110 48 0.0074 48 Turbidity (FTU)** 0.2972 45 0.0849 36 —0.0550 48 —0.2213 48 Depth (m) —0.3045 45 0.0170 36 —0.6029* 48 0.2420 48 Number of individuals Number of individuals Bottom temperature (°C) 0.5003* 45 0.5158* 36 0.0239 48 0.3385* 48 Salinity (%,,) 0.2006 45 0.1605 36 0.0187 48 0.2766 48 Oxygen (mg/liter) —0.0768 45 —0.3710* 36 —0.0614 48 —0.3089* 48 Turbidity (FTU) 0.1575 45 —0.2985 36 0.0142 48 -—0.0146 48 Depth (m) —0.1624 45 —0.1052 36 —0.1766 48 0.4652* 48 *Significant (2 + 0) at aw = 9.05. **FTU = Formazin Turbidity Units. Table 4.—Groups formed from cluster analysis of species of fishes and decapod Crustacea collected in the North and South Santee Rivers from 1975 and 1976. Dendrograms are not shown. North Santee R. Group A Lagodon rhomboides Alpheus heterochaelis Eucinostomus argenteus Group B Prionotus tribulus Dasyatis sabina Callinectes similis Gobiesox strumosus Etropus crossotus Hypsoblennius hentzi Xiphopenaeus kroyeri Group C Astroscopus y-graecum Ancylopsetta quadrocellata Ophidion marginatum Urophycis floridana Centropristis striata Urophycis regia Penaeus duorarum Group D Arius felis Peprilus alepidotus Callinectes ornatus Selene vomer Portunus gibbesii Pagurus longicarpus Clibanarius vittatus Opsanus tau Trachypenaeus constrictus Menticirrhus americanus Group E Alosa sapidissima Paralichthys dentatus Cynoscion nebulosus Muzgil cephalus Dorosoma petenense Gobionellus hastatus Rhithropanopeus harrisii Peprilus triacanthus Anchoa hepsetus Panopeus herbstii Pomatomus saltatrix Chloroscombrus chrysurus Group F Lepisosteus osseus Cyprinus carpio Palaemonetes pugio Alosa aestivalis Ictalurus punctatus Ictalurus furcatus Macrobrachium ohione Anguilla rostrata Morone saxatilis Group G Ictalurus catus Trinectes maculatus Micropogonias undulatus Anchoa mitchilli Penaeus setiferus Bairdiella chrysoura Cynoscion regalis Stellifer lanceolatus Penaeus aztecus Symphurus plagiusa Callinectes sapidus South Santee R. Group A Ophidion marginatum Ancylopsetta quadrocellata Urophycis regia Urophycis floridana Etropus crossotus Alosa sapidissima Cynoscion nebulosus Archosargus probatocephalus Lutjanus griseus Lagodon rhomboides Group B Dasyatis sabina Citharichthys spilopterus Caranx hippos Eucinostomus sp. Centropristis philadelphica Group C Hypsoblennius ionthas Trachypenaeus constrictus Menticirrhus americanus Clibanarius vittatus Hypsoblennius hentzi Penaeus duorarum Centropristis striata Opsanus tau Symphurus plagiusa Gobiesox strumosus Paralichthys dentatus Group D Pomatomus saltatrix Peprilus triacanthus Anchoa hepsetus Chloroscombrus chrysurus Panopeus herbstit Group E Cynoscion regalis Penaeus aztecus Stellifer lanceolatus Callinectes similis Peprilus alepidotus Selene vomer Lepisosteus osseus Rhithropanopeus harristi Macrobrachium ohione Group F Ictalurus punctatus Ictalurus furcatus Alosa aestivalis Group G Anchoa mitchilli Bairdiella chrysoura Callinectes sapidus Penaeus setiferus Paralichthys lethostigma Brevoortia tyrannus Leiostomus xanthurus Micropogonias undulatus Trinectes maculatus Ictalurus catus Palaemonetes vulgaris Palaemonetes pugio Dorosoma petenense BOTTOM SALINITY (%o) 2 ic > 2 2 3 Paralichthys lethostizma Brevoortia tyrannus Leiostomus xanthurus Palaemonetes vulgaris The classification based on the quantitative similarities of distribution of species found in the North and South Santee Rivers produced the species groups shown in Table 4. In order to determine affinity of species assemblages along the estuarine gradient, we compared species group constancy and fidelity among the eight stations occupied in the North and South Santee Rivers during 1975 and 1976 (Fig. 3). This was deemed preferable to comparing site groups determined by cluster analysis with species groups because site groups broadly overlapped and were not clearly separated by cluster analysis ac- cording to salinity regimes within the estuary. In the North Santee River, one species group (G) was con- sistently encountered at stations NSOI and NS04, with slight decline in constancy at NSO7 and NS11 (Fig. 3). Species in this group were not restricted in their distribution to any station location but were ubiquitous over the sites sampled, which is an indication of their apparent euryhalinity. The other species groups were not consistently collected at any of the stations, as indicated by low constancy. Species group B, which is largely composed of coastal marine fishes, was entirely restricted to sta- tion NSO1, which suggests the stenohaline nature and transient occurrences of these fishes within the estuary. Other groups (A and D) were also apparently composed of marine species which were not able to penetrate far into the estuary. Group E species were associated with intermediate to higher salinities and did not North Sante —— Mile | Ee see Mile 4 3275 Se (Neer Figure 3.—Two-way coincidence tables of constancy and fidelity which compare species associations with stations in the North and South Santee Rivers, 1975-76. The species associations, designated alphabetically, resulted from cluster analysis of species (dendrogram not shown) collected from the Santee system. Species compris- ing these associations are listed in Table 5. occur at stations upriver from NS04. Members of group F were not found downestuary of station NSO7. In the South Santee River, species in group G were considered to be ubiquitous over all sites. The constancy of these species ranged from high at stations SS04 and SS0O7 to moderate at SSO1 and SS11; however, species in this group were not restricted to any station location. Groups A, C, and D included species which were associated with higher salinity areas in proximity to the river mouth. Stenohaline marine species in these groups in- cluded sheepshead, Archosargus probatocephalus; black sea bass, Centropristis striata, butterfish, Peprilus triacanthus; and Atlantic bumper, Chloroscombrus chrysurus. Group B species were not consistently collected at any station location and displayed low fidelity to stations SS04 and SS11. These species are generally considered to be marine in origin and their penetra- tion as far as SS11 is unusual. Species which were associated with higher and intermediate salinities constituted group E. These were found at all stations except SS11, but were not con- sistently collected at any site. Group F contained the stenohaline freshwater species, Jctalurus punctatus and I. furcatus, and the anadromous species, blueback herring, A/osa aestivalis, which were restricted to station SS11. Based on results of the two-way coincidence table (Fig. 3), it was possible to distinguish four assemblages of fishes and decapod Crustacea in both the North and South Santee Rivers. The first assemblage consisted of euryhaline species which oc- curred throughout both rivers and included the fishes Anchoa mitchilli;, Brevoortia tyrannus; Trinectes maculatus; Micropogonias undulatus; Leiostomus xanthurus; Bairdiella chrysoura; southern flounder, Paralichthys lethostigma; and I. catus; and the decapods Penaeus setiferus, Callinectes sapidus, and Palaemonetes vulgaris, grass shrimp. Coastal marine species, which may penetrate into the estuary for short periods of time, constituted the second assemblage. Species in this category included the fishes Centropristis striata; skilletfish, Gobiesox strumosus; feather blenny, Hypsoblennius hentzi; southern kingfish, Menticirrhus americanus; and_pinfish, Lagodon rhombiodes—and the decapods pink shrimp, Penaeus duorarum, and humpback shrimp, Trachypenaeus constrictus. The third assemblage consisted of species which can tolerate a range of intermediate to low salinities. Rhithropanopeus har- risiti, mud crab, which occurs in both the North and South Santee Rivers, was distributed in this manner. The fourth assemblage was composed of the stenohaline freshwater species Ictalurus punctatus, I. furcatus, and the anadromous species, Alosa aestivalis. Although the formation of these categories is based on distributional patterns formed from an actual collection of the organisms, it remains an artificial attempt at forcing species into designated groups based on their general affinities within the estuary. Therefore, it is possible and certainly probable that species will encounter others outside their group and may even form peripheral associations. This is especially true of the euryhaline species which are capable of widespread penetration of the estuarine environment. Temporal and Spatial Distributions—Fishes Temporal and spatial distributions for four abundant species of fishes—Micropogonias undulatus, Anchoa mitchilli, Ic- talurus catus, Bairdiella chrysoura, and Trinectes maculatus— are compared in Figures 4-6. A summary table of the distribu- tion and lengths for all species collected is available from the authors. Micropogonias undulatus, Atlantic croaker.—The Atlantic croaker was found throughout both rivers, although its presence at stations varied over the 2-yr sampling period (Fig. 4A). In the North Santee River, number and biomass of the Atlantic croaker were greatest during spring 1976 at NSO7. This is in marked contrast to spring 1975 when none were collected at this station or at NS11 further upriver. The absence of croaker at these stations in 1975 may be attributed to the significant altera- tion of physicochemical properties by the freshet in spring 1975. A similar decrease in abundance was not noted in the South Santee River, but failure to occupy SS11 during 1975 precludes a true assessment of freshet effects far upriver. The apparent absence of Atlantic croaker at upriver stations in the North Santee River during fall 1976 cannot be readily attributed to any hydrographic parameter but may reflect a lag in recruitment of young fish during this period. Length-frequency distributions (not shown) indicated that sizes of most Atlantic croaker available to our bottom trawls were <10 cm in both rivers during all seasons. The predominance of smaller fish accounts for the low biomass observed for Atlantic croaker. Young fish, 4-16 cm, were prevalent in both rivers during fall and winter. A few larger fish which ranged from 12 to 26 cm were also present, but their num- bers were low, which could reflect gear avoidance, movement away from the channel, or emigration from the estuary. Size of young Atlantic croaker had increased to a mode of 8-9 cm by summer and abundance had increased. Others (Haven 1957; Hansen 1969; Hoese 1973; Shealy et al. 1974; Chao and Mu- sick 1977) have noted that small Atlantic croakers are pres- ent in different estuarine systems along the east coast through- out much of the year. The abundance of young fish in the Santee system is probably related to the long spawning season of the Atlantic croaker (Chao and Musick 1977), which may be more protracted in South Carolina waters than in temperate northern estuaries, although our choice of sampling gear, biased toward capture of smaller fish, is undoubtedly also a factor. Anchoa mitchilli, the bay anchovy.—Anchoa mitchilli was found at all stations in both the North and South Santee Rivers sometime during the 2-yr sampling period, but catches were generally greater in the South Santee River (Fig. 4). Abundance of A. mitchilli appeared to be lowest at low-salinity stations located further upriver in both rivers. This decreased abundance was especially noticeable in spring and summer. During these seasons, bay anchovy were found at more seaward stations within the estuary. This distributional pattern is similar to that observed in the Edisto and Cooper Rivers, S.C. (Shealy et al. 1974), and York River, Va. (Markle 1976). Length-frequency distributions for A. mitchilli were strongly bimodal with smaller (20-35 mm) and larger (50-75 mm) fish cooccurring during most seasons (not shown). These data do not indicate an influx of small fish into the population during a particular season, such as summer (Hoese 1973; Shealy et al. 1974), but suggest that small fish are present in the Santee system throughout the year. Multiple spawns (Hoese 1965) or a protracted spawning season (Hildebrand and Cable 1930) best explain the bimodality of frequencies observed for bay anchovy in the Santee system. Similar findings were noted by Hoese (1965), who believed that A. mitchilli spawns during all seasons in Texas and probably is short-lived. In addition, Mansueti and A. Micropogonias undulatus N FALL aS a i) i= oO wo 4 =) ° ° ° NUMBER ° NSO! NSO4 NSO7 NSII SSO! SSO4 SSO7 SSII st} hs he he —$§ter- BIOMASS {e) 2) NUMBER ° NO COLLECTION NSO! NSO4 NSO7 NSII SSO!I SSO4 SSsO7 SSII gg et fa te tr BIOMASS {o} a SPRING us}os NUMBER ° NO COLLECTION NSO! NSO4 NSO7 NSII SSOl SSO4 SSQO7 SSI! cot PS ionis Be ital BIOMASS fo) a INDEX OF RELATIVE ABUNDANCE NUMBER re) ailro NO COLLECTION NSO! NSO4 NSO7 NSIi SSO! SSU4 SSO7 SSII BIOMASS fo) oO []1975 B. Anchoa mitchilli 2 < 3 ° 3 2 20 FALL 7 w a $ 3 = mii oO 2 3 2 NSO| NSO4 NSL7 NSII SSOI Ssl4 SSU7 SSI! , sas he ep} to te he 1 - ") 6 =05 2 oa 1.0 WINTER amen) se 2.0 3 3 = ec — w 3 a a a = 1.0 2 2 o = ° z NSO! NSO4 NSO7 NSII SSO! SSO4 SSO7 SSI! 2 no Jos is) {oa} SPRING NO COLLECTION ai[ro (= NUMBER NSOI NSO4 NSO7 NSII SSOl SSO4 SSO7 SS “ta tens — tes hes — he —§$+ to INDEX OF RELATIVE ABUNDANCE wn n Jos ° o 1.0 SUMMER z fe} 3 3 S Para liey 3 5 6 a = s 1.0 ro} =) oO rs ° rs NSU! NSO4 NSO7 NSI! SSO! SSO4 SSsO7 SSII —t—_}+—__+ Cop er ts = wn Yn gos ie] oo Bisve Figure 4.—Abundance of A) Micropogonias undulatus and B) Anchoa mitchilli by station and season for the North and South Santee Rivers. Ratios over bars indicate number of collections where fishes were captured to total number of collections at a station. Hardy (1967) found sexually mature individuals at 2.5 mo of age in the Chesapeake Bay system. Ictalurus catus, white catfish.—The distribution of J. catus was obviously influenced by salinity since catches declined markedly at higher salinity stations (Fig. 5A). In the North Santee River, catches of I. catus were greatest during all seasons at stations furthest upriver. Distributional patterns in the South Santee River were similar in that J. catus seldom occurred at higher salinity stations. Shealy et al. (1974) found no J. catus at estuary mouths of the North and South Edisto or Charleston Harbor-Cooper Rivers. The infrequent occurrence of white cat- fish at the mouth of the Santee River probably reflects the often low-salinity nature of the Santee River and the subsequent penetration by lower salinity species. High biomass of /. catus corresponded with peak numerical abundance in both rivers. Length-frequency distributions (not shown) showed that’most white catfish collected in the Santee system were <100 mm, although the length range extended from 10 to 370 mm. Based on an age-growth study of /. catus from South Carolina (Stevens 1959), the fishes <100 mm are not older than 2 yr. In the North Santee River, young-of-the-year fish (< 50 mm) were A./cta/lurus catus 20 Sp dz ac Ww a = =) es NSO| NSO4 NSO7 NSIl SSO! $SO4 Sso7 SSII ip) a = 0.5 ) ea} 1.0 uJ WINTER On O za a ae Zz? =) oo NSOI NSO4 NSO7 NSII SSO! SSO4 SSO7 SSII r<§ Cr ae El a Z = 0.5 ce) lj o > 1.0 = s 3 SPRING LJ wi 2 =e \ see = t Al 2 3 T T 6 NSO| NSO4 NSO7 NSII SSOl $S04 SSO7 SSII wn wn < go05 fo) LJ oO a 1.0 a 20 2 SUMMER ac 2 > As WwW = S10 2 P 5 dilaee sully \ fi x zs Same Ey ny a NSO] NSO4 NSO7 WSII SSOl SSO4 SSO7 SSII os 2) = | 179) a =o : 3) ao a [ jis75 Figure B. Bairdiella chrysoura a Ww wo = =) 73 NSO!| NSO4 NSO7 NSII sso! sso4 sso7 SSII - al — J | lie =: to w = 05 ° oe 19 re) WINTER O 20 z th ng 1.0 E tn SPRING 2) a a WJ o Bsa 2 ssi ltOas evo 3 3 2) @ 5 Ee tee (in lie = 3 Le NSO! NSO4 NSU7 NSII SSOI SS04 Sso7 ssII Oo Rotem ee ea wn wn x< = 054 oO uJ = | ran) 1.0 z -- 3 20 SUMMER ; = a 3 3 Ww 3 3 2 iea) = 3 7 (| 3 KS = 1.0 3 = oS : 3 0 4 3 Z 2 di h 5 1s NSO! NSC4 NSO7 NSII sso! sSsc4 Ssso7 SSII wn 2 =.0:5) [o} o 1.0 & 1976 5.—Abundance of A) /efalurus catus and B) Bairdiella chrysoura by station and season for the North and South Santee Rivers. Ratios over bars indicate number of collections where fishes were captured to total number of collections at a station. prevalent in summer, which is coincidental with the spawning period of /. catus in South Carolina (Stevens 1959). Bairdiella chrysoura, the silver perch.—Bairdiella chrysoura was present in the Santee system during all seasons, although abundance tended to increase during fall and summer in the South Santee River (Fig. 5). Silver perch showed no apparent preference for a particular portion of the salinity regime in the middle and lower reaches of the estuary since they were collected at all stations; however, catches did decline at the stations located further upriver (NS11 and SS11). Bairdiella chrysoura taken from the Santee system were young-of-the-year fish (Shealy et al. 1974; Chao and Musick 1977) within the size range of 20-100 mm. Trinectes maculatus, hogchoker.—Trinectes maculatus was ubiquitous in the Santee system during all seasons (Fig. 6). Catches were greatest during fall in both the North and South Santee Rivers. Lower catches tended to be associated with sta- Trinectes maculatus FALL 3 3 NUMBER sso! SSO4 SSO7 SSII w q z 205 se) © 1.0 NSO! NSO4 NSO7 NSII NUMBER NSOI NSO4 NSO7 NSII SSOI SSO4 SSO7 SSII BIOMASS = © (oe) oO NUMBER NSOI NSO4 NSO7 NSII SSOI SSO4 SSO7 SSII 5 1.0 SUMMER INDEX OF RELATIVE ABUNDANCE BIOMASS NUMBER NSO!I NSO4 NSO7 NSII wn a = 05 fe) a bao OJ 1975 B® i976 Figure 6.—Abundance of Trinectes maculatus by station and season for the North and South Santee Rivers. Ratios over bars indicate number of collections where fishes were captured to total number of collections at a station. Ssol SSO4 SSO7 SSII tions in proximity to the river mouths, which suggests an avoidance of euhaline areas by this fish. Lengths of hogchokers ranged from 20 to 175 mm, but most individuals were < 80 mm. These specimens probably represent young-of-the-year fish (Dovel et al. 1969) which appear during all seasons due to the ex- "Bearden, C. M. 1961. tended spawning season of this species in the Carolinas (Hildebrand and Cable 1938). Temporal and Spatial Distributions—Decapods Distributional patterns of the most abundant decapod crusta- ceans, P. setiferus, P. aztecus, and Callinectes sapidus, are shown in Figures 7 and 8. Penaeus setiferus, white shrimp.—Catches of white shrimp were seasonal, with most individuals occurring in the Santee system during the fall and summer. Though common in both rivers, numerical abundance and biomass of white shrimp were greater in the South Santee River (Table 2), and catches ap- peared to be lower at the extreme upriver stations. This was par- ticularly evident during winter and spring. Length-frequency distributions showed young-of-the-year white shrimp were pres- ent during summer in both rivers (Fig. 7). Sizes of shrimp col- lected increased during the other seasons, with the largest in- dividuals collected in the spring. Similar findings were noted by Bishop and Shealy (1977) in a study of penaeid shrimp from South Carolina estuaries. They found that the largest numbers of shrimp were small, whereas larger individuals, which may be derived from the overwintering population or from an im- migrating offshore population, occurred during fall and spring. Penaeus aztecus, brown shrimp.—Brown shrimp were most abundant in spring and summer (Fig. 8). These brown shrimp were rare in winter trawl collections. In other South Carolina estuaries, Bishop and Shealy (1977) noted that catches of brown shrimp were strongly seasonal, with most individuals collected in summer. The absence of brown shrimp in trawl catches during the winter months does not indicate that they are absent entirely from the estuary. Postlarval shrimp first enter South Carolina estuaries in January and are most abundant in February and March (Bearden®). Because it appears that postlarval white shrimp, and perhaps also brown shrimp, primarily occupy the shallow edges and creeks of estuaries where cover and preferred food are available (Bishop and Shealy 1977), we may have failed to sample this component of the shrimp population by restric- ting our collecting to the channel. It is also probable that 9-12 mm postlarvae are not retained by our 6 m otter trawl. Ex- amination of length-frequency distributions (not shown) for brown shrimp collected in the Santee system showed a total absence of postlarvae in our trawl collections. Shrimp ranged from 30 to 145 mm, with most individuals in the 55-90 mm size range. The abundance of brown shrimp was also related to sta- tion location and, hence, salinity as reflected in only one occur- rence of P. aztecus at the extreme upriver sites. Callinectes sapidus, blue crab.—The blue crab was caught throughout the North and South Santee Rivers during all seasons. Catches did not reflect strong seasonal changes, although fewer blue crabs were collected in summer in the North Santee River. Catches also appeared to be related to sampling location, with fewer blue crabs being caught at upriver stations. Size-frequency distribution of blue crabs covered a wide range of sizes from 15 to 195 mm, with smaller crabs (< 60 mm) occur- ring in fall. Notes on postlarvae of commercial shrimp (Penaeus) in South Carolina. Contrib. Bears Bluff Lab. No. 33, 8 p. Penaeus setiferus North Santee South Santee axa FALL SPRING n=44~" \ 14 BS KN SUMMER 3 7 FAL a ess; L | 3.0 Sa ar 200-4 a Die : ‘| FALL = a 160 = © aI =| Fi 1204 NSO! NSO4 NSO7T NSII SSO! SSO4 SSO7 SSI! > aol g z Bal 40-4 5 zal w”® 1.0 aq oO R a =) = 304 WINTER ¢ iS 2 405 Shea 3 28 > 204 ® j 04 1 A Ali si = =z = 3 3m iB eo (a) TT 5: = dE Z 20> SPRING _n=5 Ps NSO! NSO4 NSO7 ANSI! SSO! SSO4 SSO7 SSII ae 3 3} = < o54 <=) a @ |1.0- iS o I 3 z = We 205 SPRING 3 2 = 2 at & = 210 3 u 3 3 oO rs < NSO! NSO4 NSO7 NSiI SSO! SSO4 SSO7 SSI! wo ad 23 =a NUMBER NSOI NSO4NSO7 NSII SSO!I SSO4 SSOT w wn F054 I | ° Os 01975 @ i976 ssil 30 TOTAL LENGTH(mm) Figure 7.—Seasonal abundance and length-frequency distribution of Penaeus setiferus within the North and South Santee Rivers. Ratios over the bars indicate number of col- lections where shrimp were captured to total number of collections at a station. Biomass Estimates The estimated biomass, expressed in kg/ha, for fishes from the North and South Santee Rivers was lower than biomass estimates reported for other estuarine systems along the Gulf and east coasts of the United States (Table 5). Greatest biomass was obtained for northern temperate estuaries such as Nar- ragansett Bay, R.I. (Oviatt and Nixon 1973), and Mystic River, Mass. (Haedrich and Haedrich 1947), while the number of fish per hectare was comparable between these northern estuaries and those in South Carolina. The reliability of our biomass estimates is confirmed by the identical value (3.8 kg/ha) obtain- ed by Shealy et al. (1974) in other South Carolina estu- aries. Table 5.—Estimates of density and number of individuals/hectare for fishes caught by trawls from estuaries along the Gulf and east coasts of the United States. Biomass Density Geographic area (kg/ha) (no./ha) Mystic River, Mass. 26.16 462 Narragansett Bay, R.1. 31.68 290 North Santee River, S.C. 3.9 287 South Santee River, S.C. 3.8 303 Cooper River — Charleston Harbor and Edisto system, S.C. 3.8 433 Doboy Sound, Ga. 10.7 4,1 Galveston Bay, Tex. 16.57 8,511 Gear 4.8 m semiballoon trawl 9.2 m balloon trawl 6 m semiballoon trawl 6 m semiballoon trawl 6 m semiballoon trawl 12.2 m balloon shrimp trawl 3 m otter trawl Reference Haedrich and Haedrich (1974) Oviatt and Nixon (1973) present study present study Shealy et al. (1974) Hoese (1973) Bechtel and Copeland (1970) A. Penaeus azfecus 20 FALL x Ww a = a bem 1 alt tf 3 Age 35 nS > —3 3 3 3 = lagers ars [hn aa NSO! NSO4 NSO7 NSII SSOI SSO4 SSO7 SSI! Oe 2 = 0.5 o LI To) 2.0 WINTER ine Sa ae Ww a = !.0 = ce T Vie NSOI ay, qaeecan NSIl SSOI SSO4 SSO7 SSII I 1! eset fe n a = 0. 5 ie) a 1.0 lope “Wis sd INDEX OF RELATIVE ABUNDANCE > SPRING [ea W [ea : f 2 a NSOI I aie nue sso! SSO4 SSO7 SSII ky ts --! egy tor g am | Ss 0.5 se) 0 1.0 3 DOs SUMMER So) lamas o s 1079 =>) z NSOI NSO4 NSO7 NSII SSOI SSO4 SSO7 SSII [Keating | es fy he —— BIOMASS i C1 1975 B oz B.Ca/linectes sapidus A FALL 3 NUMBER 3° —_ us| no ol— Cares oilr i=" a e- NSOI NSO4 NSO7 NSII SSO! SSO4 SSO7 a BIOMASS NUMBER 3 fe eo. | ae Be i a | wil BIOMASS == 2 Oo NUMBER 3° ho I- Jw wilro wal a wilro SsO!l SSO4 SSO7 SSII OF RELATIVE ABUNDANCE BIOMASS INDEX NUMBER NSOI NSO4 aia iS = 7) SSOl SSO4 SSO7 "Ty Sstl 0.5 BIOMASS 1.0 Figure 8.—Abundance of A) Penaeus aztecus and B) Callinectes sapidus. Ratios over the bars indicate number of collections where shrimp were captured to total number of collections at a station. We obtained the following density estimates of decapod Crustacea from the Santee system: Biomass Density (kg/ha) (no./ha) South Santee S55) 836 North Santee 1.9 255 These estimates are comparable to 6.1 kg/ha and 1,190 in- dividuals/ha reported by Hoese (1973) for all invertebrates col- lected from Doboy Sound, Ga. DISCUSSION The distributional patterns of estuarine fishes and decapod Crustacea are influenced by numerous environmental factors. Factors such as salinity (e.g., Gunter 1938, 1945, 1961; Kilby 1955; Kinne 1966; Copeland and Bechtel 1974), temperature (Gunter and Hildebrand 1951; Reid 1954; Kinne 1963), substrate and detritus (Carr and Adams 1973; Mills 1975; Livingston et al. 1977), and river discharge (Aleem 1972; Ruello 1973; Livingston et al. 1977; Glaister 1978) influence animal distributions, with the extent of these influences dependent on spatial (habitat) dimensions as well as individual and specific tolerances. Laboratory studies are generally concerned with the interrela- tionships between biological response and multiple environ- mental factors acting in concert. However, application of laboratory methodology to ecological field studies is often quite difficult (Alderdice 1972), especially when dealing with mobile organisms such as fishes and decapods. The interpretation of results concerning distribution of these organisms within the Santee system is no exception to this difficulty. Nevertheless, it is possible to make some interpretation of community stability and specific distributional patterns based on the information collected over the intensive 2-yr sampling period. The freshet in spring of 1975 appeared to have the most pro- nounced singular effect on species composition and abundance. The total number of species collected was lower at that time than at any other during the sampling period. This was par- ticularly noticeable at the upriver stations. Abundance of in- dividual species such as Micropoganias undulatus, Anchoa mitchilli, and Trinectes maculatus were also lower at these sta- tions, which also may be attributable to flood effects. The ef- fects on the decapod crustaceans and other numerically domi- nant fishes were not obvious. Calder et al. (1977) also reported alterations of species composition and density among benthic organisms collected from the Santee system during 1975 and 1976; however, they noted that the flood most affected benthos in the lower, usually more saline reaches of the river where an in- crease in species normally associated with greater freshwater in- trusion into the lower estuary occurred. Others (Andrews 1973; Boesch et al. 1976) have noted that effects of lowered salinity from floods are greatest among meso- or polyhaline species, but the magnitudes of the effects differ for epifaunal, infaunal, and highly motile organisms. The depressed species number ob- served by us may reflect the tendency of fishes and decapods to escape from areas whose salinity is drastically lowered by flood- waters or, in the case of juveniles and small-bodied species, may be attributed to their being flushed downstream and out of the system. The positive correlation between salinity and number of species in the Santee system agrees with results obtained by Gunter (1961), who noted that the number of species increased toward the lower reaches of estuaries where there occurred a mixture of euryhaline and marine stenohaline species. Hoff and Ibara (1977) found that in a New England estuary the number of species was greatest at stations which had the greatest fluctua- tion in salinity. Both species number and the community assemblages defined by us for the Santee system reflect in- creased diversity with proximity to the river mouth. Also, most assemblages defined for the Santee system consisted partially of euryhaline species. This is not an unusual occurrence within estuaries. Pearse (1936) noted that the estuarine fauna consists of marine or marine-derived species, and Weinstein (1979) stressed how depauperate the shallow marsh estuarine fauna would be if all transient marine species were removed. The distribution of the endemic estuarine species appeared to be more restricted than that of the marine transients. Nevertheless, we observed no abrupt faunal changes along the salinity gradient in the Santee system. Rather, the faunal assemblages overlap and do not exist as sharply delineated groups. This no doubt results from the different tolerances of juveniles and adults; the effect of salinity, in concert with other factors, on reproduction; and the highly compressed nature of salinity regimes in South Carolina estuaries as compared with many estuaries elsewhere. 14 As indicated by Pearson product-moment correlations, temperature, depth, and dissolved oxygen also affect com- munity composition and abundance. The positive correlation of number of species and number of individuals with temperature is not at all surprising when one considers that species composi- tion was most diverse during summer in both rivers. The huge influx of Penaeus setiferus and, to a lesser extent, P. aztecus into the estuary during summer and fall probably accounts for this correlation. The association between depth and number of species and individuals is more difficult to explain. All collec- tions were made in the channel where depths ranged from 2 to 8 m in the North Santee River and from 1 to 5 m in the South Santee River. Although the range in depths sampled is slight, sufficient salinity stratification may exist in the Santee system so that higher salinity water occurs in the deeper channel regions. This may indeed be true for the South Santee River which receives less freshwater input. Also, salinity stratification may be greater on the floodtide, where samples were collected (Mathews footnote 4.) Since there is a positive correlation of species number and abundance, the correlation between depth and species composition and abundance is most likely a secondary effect. Similarly, the negative association between dissolved oxygen and abundance which was noted only for the South Santee River may be explained by lower dissolved oxygen values in the deeper, more saline channel areas. We realize the correla- tions are simplistic and that misinterpretation can result from speculating about cause and effect relations in correlation analysis (Sokal and Rohlf 1969). We are merely presenting this information as untested hypotheses. Peaks of abundance for the numerically dominant species were not generally consistent over the 2-yr sampling period, but peaks of maximum richness (number of species) consistently oc- curred in summer. This observation compares favorably with those of Livingston et al. (1976) for fishes and invertebrates of Apalachicola Bay, Fla. They noted a relatively stable ap- pearance of organisms from year to year, but considerable within-species variability in annual abundance. Temporal parti- tioning by our dominant species was not as noticeable as that described by Livingston et al. (1976). Dominant fishes were present in the Santee system throughout the year and showed fairly equitable abundances, although M. undulatus and A. mitchilli dominated our catches in winter and spring. Penaeus setiferus was much more regular in its pattern of appearance and abundance. Although regular fluctuations in species composi- tion over time may indicate that an estuary is not stressed (Liv- ingston et al. 1976), we feel that the year-round presence of stress-tolerant estuarine species better indicates temporal stability than overall stability of the estuarine system. We relate such oc- curance to a protracted spawning season in warm temperate areas which enable some element of the population, probably juveniles, to be present in the estuary year-round. As the length-frequency polygons for selected species showed, the Santee system fish fauna captured during this study are primarily composed of immature fishes. Some larger mature in- dividuals were collected, but the Santee system functions strongly as a juvenile fish habitat. The importance of estuaries as nursery areas is well documented (Gunter 1961; Wallace and Van der Elst 1975; Livingston et al. 1976; Weinstein 1979), and the attraction of young fish to estuaries is attributed to physiological suitability in terms of physiochemical features, an abundance of food, and protection from predators (Gunter 1961; Van Engel and Joseph 1968’; Wallace and Van der Elst 1975). Although Wallace and Van der Elst (1975) and Livingston et al. (1976) also found that juveniles predominated in their samples, we suspect that sampling design and gear selectivity may have biased our results toward juvenile fishes. Our choice of fixed stations is certainly biased and lends itself to sampling error that would have been eliminated or reduced by a stratified random design (Markle 1976). We are, therefore, not able to determine the influence of movements by the fauna between the shoals and the channel. Because trawling is inherently variable (Taylor 1953), a repetitive method of collection would have allowed for statistical analysis of sampling efficiency to deter- mine whether hauls taken at different times in different places did indeed have significantly different catches (Barnes and Bagenal 1951; Livingston 1976). However, even with successive samples, it is difficult to determine whether variability arises from the spatial distribution of the organisms or from the gear utilized (Taylor 1953). The susceptibility of organisms to fishing gear undoubtedly has influenced perception of spatial and tem- poral patterns (Markle 1976). The relatively small, fine-mesh bottom trawl used in our study is selective toward capture of slower, smaller fish. The relative absence of great numbers of older, larger fish from our trawl catches cannot be attributed en- tirely to migration or habitat selection, but in all likelihood reflects at least partial avoidance or escapement from the 6 m trawl (Shealy et al. 1974). Habitat differences between adult and juvenile fishes may also account for the lack of large fish in our samples. Habitat preference varies with the species and also with age (Wallace and Van der Elst 1975; White and Chittenden 1976), so that feeding and residential grounds of adult fishes often are separate from their spawning grounds and nurseries. If spatial separation exists in South Carolina waters, then our survey was biased toward collection of juveniles found primarily in the channel. However, tidal creeks of the Cooper River which are comparable in sa- linity to those near the intermediate and upriver stations oc- cupied in the Santee system were dominated by young-of-the- year marine euryhaline species such as M. undulatus, A. mitchilli, L. xanthurus, B. chrysoura, and Paralichthys lethostigma (Turner and Johnson 1974). Although the impor- tance of tidal creeks in the Santee system as nursery areas can only be inferred, it is likely that the limitation of our survey to the channel resulted in minimal estimates of juvenile abundance for the river system. The lower estimated biomass of fishes in the Santee system and other South Carolina estuaries is a direct function of the predominance of juvenile fishes in our catches and the effi- ciency of the sampling gear used. Whereas the density of fish from this area compares favorably with other regions, the biomass is much less. The large biomass of fishes in New England estuaries is primarily due to large catches of winter flounder, Pseudopleuronectes americanus (Oviatt and Nixon 1973; Haedrich and Haedrich 1974). A comparison of biomass and density estimates from this study and others (see Table 5) which used small trawls towed in the channel with investigations which incorporated shallow tidal creek and marsh sampling (e.g., Turner and Johnson 1974) indicates that the most produc- tive areas are the marsh-creek habitat. Because these areas of the system were not sampled and the efficiency of our gear was low, "Van Engel, W. A., and E. B. Joseph. 1968. Characterization of coastal and estuarine fish nursery grounds as natural communities. U.S. Fish Wildl. Serv. Final Rep., 43 p. our biomass and density estimates should also be considered minimal. The presence of juvenile fishes in the Santee system is especially important in considerations concerning the effects of rediversion. Juvenile stages of resident species and many estuarine transient species are tolerant of and may even be most abundant in lower salinity water (Gunter 1961). Therefore, we believe that the nursery habitat for resident estuarine fishes will not be detrimentally affected and may be increased by re- diversion. Because rediverted flow of water through the Santee system will be moderate compared with the tremendous discharge of freshwater (9,100 m?/s) put into the Chesapeake Bay estuarine system by Hurricane Agnes (Chesapeake Bay Research Council 1973), we do not anticipate that juvenile fishes will be passively swept from the Santee Rivers into the coastal area. In contrast, the food supply of fishes may be altered in that sup- plies of benthic organisms could increase in oligohaline and brackish water areas but decrease in lower reaches of the river. This effect could be particularly detrimental if it occurred during summer. Andrews (1973) noted that floods during warm seasons cause silting and an influx of excessive nutrients and organic matter, with consequent algal blooms and stratification of waters. These factors may, in turn, lead to low dissolved oxygen conditions. During other seasons, increased accumula- tions of detritus caused by increased riverflow and salinity alterations could actually be beneficial to microorganisms and detritivores such as isopods, amphipods, and some decapods. Detritus also serves as the major energy base utilized by juveniles of most fish species from sea grass beds (Carr and Adams 1973) and is probably important as a direct or indirect source of food for many fishes in the Santee system. Sustained abundance of Penaeus setiferus in the Santee system is questionable following rediversion. Shrimp are known detritivores, and large areas of brackish/salt marsh and estuary with substantial land runoff are considered to be conducive to good shrimp production (Bishop and Shealy 1977). Rediversion will cause waters to inundate many areas and should result in a seaward progression of freshwater and brackish water plant communities. Because the total area of estuarine habitat should effectively be moved seaward, a decrease in actual acreage available as nursery habitat may result; yet lower salinity condi- tions are still likely to exert the greatest influence on shrimp pro- duction. Young P. setiferus are most abundant in salinities <10%., whereas young P. aztecus are most abundant in salinities from 10 to 207, (Gunter et al. 1964). Despite these op- timum ranges, Barrett and Gillespie (1973, 1975) have suggested that an inverse relationship exists between the amount of freshwater introduced into coastal Louisiana and the catches of brown and white shrimp. Also, increased turbidity and hyper- trophy may inhibit photosynthesis so that an initial reduction in oxygen may occur in bottom waters. Others (Hildebrand and Gunter 1953; Copeland 1966; Aleem 1972; Glaister 1978) have noted a positive relationship between shrimp abundance and river discharge, but not all of these studies indicated that abun- dance was increased within the estuary. Blue crabs will probably be little affected by rediversion be- cause of their high mobility and tolerance of low-salinity condi- tions, but increased siltation from rediversion could hamper their respiration. Although blue crab populations sustained little damage following Hurricane Agnes, mortalities in Chesapeake Bay were attributed to increases siltation, low dissolved oxygen levels, and red tide (Chesapeake Bay Research Council 1973). 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 poikilotherms to environ- mental factors acting in concert. /n O. Kinne (editor), Marine ecology - a comprehensive, integrated treatise on life in oceans and coastal waters, Vol. 1, Part 3, p. 1659-1722. Wiley-Interscience, N.Y. ALEEM, A. A. 1972. Effect of river outflow management on marine life. (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 Mar. Biol. 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. 229 p. COPELAND, B. J. 1966. Effects of decreased river flow on estuarine ecology. 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 maculatus, in the Patuxent 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. Acad. Press, N.Y., J. Water 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 estuary in downtown Boston, Massachusetts. Estuarine Coastal Mar. Sci. 2:59-73. HANSEN, D. J. 1969. Food, growth, migration, reproduction, and abundance of pinfish, Lagodon rhomboides, and Atlantic croaker, Micropogon undulatus, near Pensacola, Florida, 1963-65. Fish. Bull., U.S. 68:135-146. HAVEN, D. S. 1957. Distribution, growth and availability of juvenile croaker, Micropogon undulatus, in Virginia. Ecology 38:88-97. HILDEBRAND, H. H., and G. GUNTER. 1953. Correlation of rainfall with Texas catch of white shrimp, setiferus (Linnaeus). Trans. Am. Fish. Soc. 82:151-155. HILDEBRAND, S. F., and L. E. CABLE. 1930. Development and life history of fourteen teleostean fishes at Beaufort, N.C. Bull. U.S. Bur. Fish. 46:383-488. 1938. Further notes on the development and life history of some teleosts at Beaufort, N.C. Bull. U.S. Bur. Fish. 48:505-642. HOESE, H. D. 1965. Spawning of marine fishes in the Port Aransas, Texas area as deter- mined by the distribution of young and larvae. Ph.D. Dissertation, Univ. Texas, Austin, 150 p. 1973. A trawl study of nearshore fishes and invertebrates of the Georgia coast. Contrib. Mar. Sci. 17:63-98. HOFF, J. G., and R. M. IBARA. 1977. Factors affecting the seasonal abundance, composition and diversity of fishes in a southeastern New England estuary. Estuarine Coastal Mar. Sci. 5:665-678. Penaeus KILBY, J. D. 1955. The fishes of two Gulf coastal marsh areas of Florida. Tulane Stud. Zool. 2(8):175-247. KINNE, O. 1963. The effects of temperature and salinity on marine and brackish water animals. I. Temperature. Oceanogr. Mar. Biol., Annu. Rev. 1:301-340. 1966. Physiological aspects of animal life in estuaries with special reference to salinity. Neth. J. Sea Res. 3:222-244. KJERFVE, B. 1976. The Santee-Cooper: a study of estuarine manipulations. Jn M. Wiley (editor), Estuarine processes, Vol. I, p. 44-56. Acad. Press, N.Y. KJERFVE, B., and J. E. GREER. 1978. Hydrography of the Santee River during moderate discharge con- ditions. Estuaries 1:111-119. LAMBERT, J. M., and W. T. WILLIAMS. 1962. Multivariate methods in plant ecology. IV. Nodal analysis. J. Ecol. 50:775-802. LANCE, G. N., and W. T. WILLIAMS. 1967. A general theory of classificatory sorting strategies. I. Hierarchical systems. Comput. J. (Lond.) 9:373-380. LIVINGSTON, R. J. 1976. Diurnal and seasonal fluctuations of organisms in a North Flordia estuary. Estuarine Coastal Mar. Sci. 4:373-400. LIVINGSTON, R. J., P. S. SHERIDAN, B. G. McLANE, F. G. LEWIS III, and G. G. KOBYLINSKI. 1977. The biota of the Apalachicola Bay System: functional relation- ships. Jn R. J. Livingston and E. A. Joyce, Jr. (editors), Proceedings of the Conference on the Apalachicola Drainage System, 23-24 April, 1976, Gainesville, Fla. Fla. Mar. Res. Publ. 26, 177 p. MANSUETI, A. J., and J. D. HARDY, Jr. 1967. Development of fishes of the Chesapeake Bay region. An atlas of egg, larval, and juvenile stages, Part 1. Nat. Res. Inst., Univ. Maryland, 202 p. MARKLE, D. F. 1976. The seasonality of availability and movements of fishes in the channel of the York River, Virginia. Chesapeake Sci. 17:50-55. MILLS, E. L. 1975. Benthic organisms and the structure of marine ecosystems. Res. Board Can. 32:1657-1663. MUSICK, J. A., and J. D. MCEACHRAN. 1972. Autumn and winter occurrence of decapod crustaceans in Chesapeake Bight, U.S.A. Crustaceana 22:190-200. J. Fish. 17 NELSON, F. P. (editor). 1976. Lower Santee River environmental quality study. Resour. Comm., Rep. 120, 60 p. OVIATT, C. A., and S, W. NIXON. S.C. Water 1973. The demersal fish of Narragansett Bay: an analysis of community structure, distribution and abundance. Estuarine Coastal Mar. Sci. 1:361-378. PEARSE, A. S. 1936. The migrations of animals from sea to land. Durham, N.C., 176 p. REID, G. K., Jr. 1954. An ecological study of the Gulf of Mexico fishes, in the vicinity of Cedar Key, Florida. Bull. Mar. Sci. Gulf. Caribb. 4:1-94. ROE, R. B. 1969. Distribution of royal-red shrimp, Hymenopenaeus robustus, on three potential commercial grounds off the southeastern United States. U-S. Fish Wildl. Serv., Fish. Ind. Res. FINR-A 5:161-174. RUELLO, N. V. 1973. The influence of rainfall on the distribution and abundance of the school prawn Metapenaeus macleayi in the Hunter River Region (Australia). Mar. Biol. (Berl.) 23:221-228. SHEALY, M. H., Jr., and J. M. BISHOP. 1979. Hydrographic and biological studies in relation to Cooper River low-flow conditions prior to river rediversion. Jn Cooper River con- trolled low-flow study, p. 139-178. S.C. Water Resour. Comm., Rep. 131. SHEALY, M. H., Jr., J. V. MIGLARESE, and E. B. JOSEPH. 1974. Bottom fishes of South Carolina estuaries, relative abundance, seasonal distribution, and length-frequency relationships. S.C. Mar. Resour. Cent., Tech. Rep. 6, 189 p. SOKAL, R. R., and F. J. ROHLF. 1969. Biometry. The principles and practice of statistics in biological research. W. H. Freeman and Co., San Francisco, 776 p. STEPHENS, D. G., D. S. VAN NIEUWENHUISE, W. H. KANES, and T. T. DAVIES. 1975. after diversion. STEVENS, R. E. 1959. The white and channel catfishes of the Santee-Cooper reservoir and tailrace sanctuary. 13th Annu. Conf. Southeast. Game Fish. Comm. p. 203-219. STRICKLAND, J. D. H., and T. R. PARSONS. 1968. A practical handbook of seawater analysis. Can., Bull. 167, 311 p. SYMPOSIUM ON THE CLASSIFICATION OF BRACKISH WATERS. 1958. The Venice System for the classification of marine waters according Duke Univ. Press, Environmental analysis of the Santee River estuaries: thirty years Southeast. Geol. 16:131-144. Fish. Res. Board to salinity. Oikos 9:311-312. TAYLOR, C. C. 1953. Nature of variability in trawl catches. U.S. Fish Wildl. Serv., Fish. Bull. 54:145-166. TURNER, W. R., and G. N. JOHNSON. 1974. Standing crops of aquatic organisms in tidal streams of the lower Cooper River system, South Carolina. Jn F. P. Nelson (editor), The Cooper River environmental study, p. 13-20. S.C. Water Resour. Comm., Rep. 117. WALLACE, J. H., and R. P. VAN der ELST. 1975. The estuarine fishes of the east coast of South Africa. V. Ecology, estuarine dependence and status. S. Afr. Assoc. Mar. Biol. Res., Invest. Rep. 42:19-27. WATHNE, F. 1959. Observations on trawl-door spread and a discussion of influencing factors. Commer. Fish. Rev. 21(10):7-15. WEINSTEIN, M. P. 1979. Shallow marsh habitats as primary nurseries for fishes and shellfish, Cape Fear River, North Carolina. Fish. Bull., U.S. 77:339-357. WHITE, M. L., and M. E. CHITTENDEN. 1976. Aspects of the life history of the Atlantic croaker, Micropogon undulatus. Texas A&M Sea Grant Publ. TAMU-GS-76-205, 54 p. WILLIAMS, W. T., and J. M. LAMBERT. 1961. Multivariate methods in plant ecology. III. analysis. J. Ecol. 49:717-729. Inverse association- yx U.S. GOVERNMENT PRINTING OFFICE: 1982—594-473/70 io ee en ALS NES on pagar aten tt 6: rr anh ohys if fi Wi lara A ha Pye ae el ee peal Lr ae). eee beri | is NOAA TECHNICAL REPORTS NMEFS Circular and Special Scientific Report—Fisheries Guidelines for Contributors CONTENTS OF MANUSCRIPT First page. Give the title (as concise as possible) of the paper and the author’s name, and footnote the author’s affiliation, mailing address, and ZIP code. Contents. Contains the text headings and abbreviated figure legends and table headings. Dots should follow each entry and page numbers should be omitted. Abstract. Not to exceed one double-spaced page. 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BIN C15700 SEATTLE, WA 98115 OFFICIAL BUSINESS NOAA SCIENTIFIC AND TECHNICAL PUBLICATIONS The National Oceanic and Atmospheric Administration was established as part of the Department of Commerce on October 3, 1970. The mission responsibilities of NOAA are to assess the socioeconomic impact of natural and technological changes in the environment and to monitor and predict the state of the solid Earth, the oceans and their living resources, the atmosphere, and the space environment of the Earth. The major components of NOAA regularly produce various types of scientific and technical information in the following kinds of publications: PROFESSIONAL PAPERS—Important definitive research results, major techniques, and special investi- gations. CONTRACT AND GRANT REPORTS—Reports prepared by contractors or grantees under NOAA sponsorship. 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NMFS is also charged with the development and implementation of policies for managing national fishing grounds, development and enforcement of domestic fisheries regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also assists the fishing industry through marketing service and economic analysis programs, and mortgage insurance and vessel construc- tion subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The Special Scientific Report—Fisheries series was established in 1949. The series carries reports on scientific investigations that document long-term continuing programs of NMFS, or intensive scientific reports on studies of restricted scope. The reports may deal with applied fishery problems. The series is also used as a medium for the publication of bibliographies of a specialized scientific nature. NOAA Technical Reports NMFS SSRF are available free in limited numbers to governmental agencies, both Federal and State. They are also available in exchange for other scientific and technical publications in the marine sciences. Individual copies may be obtained from D822, User Services Branch, Environ- mental Science Information Center, NOAA, Rockville, MD 20852. Recent SSRF’s are: 726. The Gulf of Maine temperature structure between Bar Harbor, Maine, and Yarmouth, Nova Scotia, June 1975-November 1976. By Robert J. Pawlowski. December 1978, iii+10 p., 14 figs., 1 table. 727. Expendable bathythermograph observations from the NMFS/MARAD Ship of Opportunity Program for 1975. By Steven K. Cook, Barclay P. Collins, and Christine S. Carty. January 1979, iv+93 p., 2 figs., 13 tables, 54 app. figs. 728. Vertical sections of semimonthly mean temperature on the San Francisco- Honolulu route: From expendable bathythermograph observations, June 1966-December 1974. By J. F. T. Saur, L. E. Eber, D. R. McLain, and C. E. Dor- man. January 1979, iii+35 p., 4 figs., 1 table. 729. References for the identification of marine invertebrates on the southern Atlantic coast of the United States. By Richard E. Dowds. April 1979, iv +37 p. 730. Surface circulation in the northwestern Gulf of Mexico as deduced from drift bottles. By Robert F Temple and John A. Martin. May 1979, iii+13 p., 8 figs., 4 tables. 731. Annotated bibliography and subject index on the shortnose sturgeon, Acipen- ser brevirostrum. By James G. Hoff. April 1979, iii +16 p. 732. Assessment of the Northwest Atantic mackerel, Scomber scombrus, stock. By Emory D. Anderson. Apmnil 1979, iv+13 p., 9 figs., 15 tables. 733. Possible management procedures for increasing production of sockeye salmon smolts in the Naknek River system, Bristol Bay, Alaska. By Robert J. Ellis and William J. McNeil. April 1979, iii+9 p., 4 figs., 11 tables. 734. Escape of king crab, Paralithodes camtschatica, from derelict pots. By Wil- liam L. High and Donald D. Worlund. May 1979, iii+11 p., 5 figs., 6 tables. 735. History of the fishery and summary statistics of the sockeye salmon, Onco- rhynchus nerka, runs to the Chignik Lakes, Alaska, 1888-1966. By Michael L. Dahlberg. August 1979, iv+16 p., 15 figs., 11 tables. 736. A historical and descriptive account of Pacific coast anadromous salmonid rearing facilities and a summary of their releases by region, 1960-76. By Roy J. Whale and Robert Z. Smith. September 1979, iv+40 p., 15 figs., 25 tables. 737. Movements of pelagic dolphins (Stenella spp.) in the eastern tropical Pacific as indicated by results of tagging, with summary of tagging operations, 1969-76. By W. F. Perrin, W. E. Evans, and D. B. Holts. September 1979, iii+14 p., 9 figs., 8 tables. 738. Environmental baselines in Long Island Sound, 1972-73. By R. N. Reid, A. B. Frame, and A. F. Draxler. December 1979, iv+31 p., 40 figs., 6 tables. 739. Bottom-water temperature trends in the Middle Atlantic Bight during spring and autumn, 1964-76. By Clarence W. Davis. December 1979, iii+13 p., 10 figs., 9 tables. 740. Food of fifteen northwest Atlantic gadiform fishes. By Richard W. Langton and Ray E. Bowman. February 1980, iv +23 p., 3 figs., 11 tables. 741. Distribution of gammaridean Amphipoda (Crustacea) in the Middle Atlantic Bight region. By John J. Dickinson, Roland L. Wigley, Richard D. Brodeur, and Susan Brown-Leger. October 1980, vi+46 p., 26 figs., 52 tables. 742. Water structure at Ocean Weather Station V, northwestern Pacific Ocean, 1966-71. By D. M. Husby and G. R. Seckel. October 1980, 18 figs., 4 tables. 743. Average density index for walleye pollock, Theragra chalcogramma, in the Bering Sea. By Loh-Lee Low and Ikuo Ikeda. November 1980, iii+11 p., 3 figs., 9 tables. 744. Tunas, oceanography and meteorology of the Pacific, an annotated bibliogra- phy, 1950-78, by Paul N. Sund. March 1981, iii+123 p. 745. Dorsal mantle length-total weight relationships of squids Loligo pealei and Illex illecebrosus from the Atlantic coast of the United States, by Anne M. T. Lange and Karen L. Johnson. March 1981, iii+17 p., 5 figs., 6 tables. 746. Distribution of gammaridean Amphipoda (Crustacea) on Georges Bank, by John J. Dickinson and Roland L. Wigley. June 1981, iii+25 p., 16 figs., 1 table. 747. Movement, growth, and mortality of American lobsters, Homarus ameri- canus, tagged along the coast of Maine, by Jay S. Krouse. September 1981, iii+12 p., 10 figs., 8 tables. 748. Annotated bibliography of the conch genus Strombus (Gastropoda, Strombi- dae) in the western Atlantic Ocean, by George H. Darcy. September 1981, iii +16 p. 749. Food of eight northwest Atlantic pleuronectiform fishes, by Richard W. Langton and Ray E. Bowman. September 1981, iii+16 p., 1 fig., 8 tables. 750. World literature to fish hybrids with an analysis by family, species, and hybrid: Supplement 1, by Frank J. Schwartz. November 1981, iii +507 p. 751. The barge Ocean 250 gasoline spill, by Carolyn A. Griswold (editor). November 1981, iv +30 p., 28 figs., 17 tables. 752. Movements of tagged summer flounder, Paralichthys dentatus, off southern New England, by F. E. Lux and F E. Nichy. December 1981, iii+16 p., 13 figs., 3 tables. 753. Factors influencing ocean catches of salmon, Oncorhynchus spp., off Wash- ington and Vancouver Island, by R. A. Low, Jr. and S. B. Mathews. January 1982, iv +12 p., 6 figs., 7 tables. NOAA Technical Report NUFS SSRF—758 Equipment and Techniques for Handling Northern Fur Seals we isi %, < NOLL. Roger L. Gentry and John R. Holt July 1982 U.S. DEPARTMENT OF COMMERCE Malcolm Baldridge, Secretary National Oceanic and Atmospheric Administration John V. Byrne, Administrator National Marine Fisheries Service William G. Gordon, Assistant Administrator for Fisheries The National Marine Fisheries Service (NMFS) does not approve, rec- ommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales pro- motion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication. liTinlite te ome aegis cob Coe CORE Oo CUCODOO GOT USS doa GODNO COED GEOMICOREES Gunoo > TORMOOLIS 6 NAmI nA ROrCOTmErrceor 1 HPIPOEANCE OL DEHAVIOL)-/.)s areseverstarosets terest aTaistsnatetareeacavanaysrs aletueenotete tae ov narhat a ShatoPtPepE Hoss CANA AEST oF sVleletsolecele.s o1s%ese/s\e15i6/0 1 WescripsonsOhequipment syn crier Pye eee ee te OR PNR RNR accra ck ci esas cniisee cect ycy el anedouosetetevesetele reset eters yvoretereoleterecscs: syoxefeiresorett Dy N@@Ss PO booseysersoagauusasbaanD quo ane Caan Oe TOTO a mOmn AA tram iaaA rir ht oo aceon Com are CO Gort emor tan 2 mb en pots wasn cndybcurndhe Coss ON Ren OS OOOO S HEE ACR etc Ene EEA Cio koraci cocnaninD contaOs mono 2 RES CraUIAIT 4 DAT ary sy Seay are ale ees eee SeRT ov eve recep cre otra NST aRORS Voxcy Rede ec ovat ave eee Poue re boheeal resus se i cketesunebetvas revarereGuaereieysnnveveconere DZ, FAO AO WD OTe veep etcetera si erctr eres eeretoe ou enaWar sek fovea Carat fons rs ua pen cies scala ces ais inereteoessNunt ater afe meee eastansias sieges Recsicee eats 4 NESS 0 ¢ 06.0 SAR GOO MCOT AA ROO ODA UDO AOs GHG Oecho ne EAS OE SoL tet clon RiGee Sire Sa CE TE NE ECPM CR Io Ceri Oramaic imine ae Cun 4 THATS DE LOSS ohosapachaanosAbAcansAnanonaSDeRHnN bd doo con COADAMTUDCONnANOnA RED OUAeOUD Dab ooo dnd anu nad 4 ANauiltemalenmarkine Dox rsvppeve seis Poyssohel oles see kenese Tone oe sTerctacaeR ToS oho uct Tene Tel ever absense suey eu ie vevotoyel