Table 1. — Continued. 





Total 



Percent of 



Total 



Percent 



Species 



no. 



total catch 



weight 



weight 



South Santee River. — Cont. 











Anguilla rostrata 





0.01 



0.150 



0.09 



Mugil curema 





0.01 



0.040 



0.02 



Goblonellus hastatus 





0.01 



0.009 



0.01 



Prionotus carolinus 





0.01 



0.001 



<0.01 



Prionorus sp. 





0.01 



0.002 



<0.01 



Cyprinus carpio 





0.01 



1.562 



0.91 



Gobionellus shufeldti 





0.01 



0.002 



<0.01 



Diapterus olisthostomus 





0.01 



0.022 



0.01 



Chilomycterus schoepfi 





0.01 



0.085 



0.05 



Monacanthus hispidus 





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 (NS07, 

 NS11, and SS07). 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 NS01, NS04, and NS07 were represented by 

 nearly equal numbers of collections; 2) a group in which collec- 

 tions at station NS01 predominated; and 3) a group which was 

 most distinct from the other groups and was dominated by col- 

 lections made at station NS1 1 . Two major groupings of stations 

 were indicated by cluster analysis for the South Santee River: 1) 

 a group consisting mostly of collections from stations SS01 and 

 SS04, and 2) a group consisting predominantly of collections 

 from stations SS07 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 





Total 



Percent of 



Total 



Percent 



Species 



no. 



total catch 



weight 



weight 



Species 



no. 



total catch 



weight 



weight 



North Santee River: 











South Santee River: 











Penaeus seliferus 



34,998 



90.08 



121.703 



48.38 



Penaeus seliferus 



10,431 



78.80 



44.333 



44.98 



Penaeus aztecus 



1,556 



4.00 



13.393 



5.32 



Penaeus aztecus 



1,726 



13.04 



10.242 



10.39 



Callinectes sapidus 



1,318 



3.39 



114.709 



45.60 



Callinectes sapidus 



568 



4.29 



42.763 



43.39 



Palaemonetes vulgaris 



510 



1.31 



0.228 



0.09 



Macrobrachium ohione 



120 



0.91 



0.414 



0.42 



Palaemonetes pugio 



255 



0.66 



0.125 



0.05 



Palaemonetes pugio 



90 



0.68 



0.047 



0.05 



Penaeus duorarum 



95 



0.24 



1.036 



0.41 



Palaemonetes vulgaris 



89 



0.67 



0.052 



0.05 



Panopeus herbslii 



23 



0.06 



0.085 



0.03 



Trachypenaeus constrictus 



83 



0.63 



0.071 



0.07 



Ponunus gibbesii 



19 



0.05 



0.016 



0.01 



Callinectes similis 



31 



0.23 



0.184 



0.19 



Callinectes similis 



18 



0.05 



0.161 



0.06 



Penaeus duorarum 



17 



0.13 



0.077 



0.08 



Trachypenaeus constrictus 



18 



0.05 



0.019 



0.01 



Clibanarius vitlatus 



16 



0.12 



0.024 



0.02 



Rhithropanopeus harrisii 



17 



0.04 



0.013 



0.01 



Pagurus longicarpus 



12 



0.09 



0.006 



0.01 



Clibanarius vitlatus 



13 



0.03 



0.024 



0.01 



Xiphopenaeus kroyeri 



12 



0.09 



0.030 



0.03 



Portunus spinimanus 



5 



0.01 



0.008 



<0.01 



Rhithropanopeus harrisii 



10 



0.08 



0.134 



0.14 



Macrobrachium ohione 



3 



0.01 



0.028 



0.01 



Portunus spinimanus 



7 



0.05 



0.104 



0.11 



Xiphopenaeus kroyeri 



2 



0.01 



0.004 



<0.01 



Callinectes similis or ornatus' 



7 



0.05 



0.018 



0.02 



Panopeus occidentalis 



2 



0.01 



0.002 



<0.01 



Callinectes ornatus 



5 



0.04 



0.031 



0.03 



Panopeus sp. 



1 



<0.01 



0.001 



<0.01 



Panopeus herbslii 



4 



0.03 



0.006 



0.01 



Alpheus helerochaelis 



1 



<0.01 



0.001 



<0.01 



Portunus gibbesii 



3 



0.02 



0.007 



0.01 



Total 



38,854 





251.556 





Alpheus helerochaelis 

 Acetes americanus 

 Ovalipes ocellatus 

 Eurypanopeus depressus 

 Xanthidae' 

 Total 



2 

 1 

 1 

 1 

 1 

 13,237 



0.02 

 0.01 

 0.01 

 0.01 

 0.01 



0.002 

 0.001 

 0.002 

 0.001 

 0.008 

 98.557 



<0.01 



<0.01 



<0.01 



<0.01 



0.01 



Field identification. 

 'Specimen damaged and unidentifiable, not included in analyses. 



