FISHERY BULLETIN VOL. 77 NO 2 



headwaters of the marsh creek where flows were 

 minimal throughout the tidal cycle, and at Hech- 

 tic Creek which also "dead-ends" a short distance 

 upstream. Median particle size, computed as the 

 geometric mean for all core samples collected at 

 the site, generally fell within a narrow range, with 

 the exception of the Baldhead Creek rotenone sta- 

 tion where larger particles were associated with 

 the medium sand fraction. The percentage of this 

 fraction was considerably greater (349; ) than at 

 other localities. 



Intcrstation Comparisons 



Species richness was greatest at the Baldhead 

 Creek stations, closest to the ocean entrance, 

 while the total number of individuals captured 

 varied among sites (Table 3). The low catch at 

 Barnards Creek is reflected in the reduced sam- 

 pling effort at this station which was first sampled 

 in April. Catches at Walden Creek were similar tp 

 those at Baldhead Island, although fewer taxa 

 were collected. On a seasonal basis, peak total 

 abundance occurred mainly in the winter and 

 early spring, coincident with the presence of win- 

 ter-spawned species, primarily spot, Leiostomus 

 xanthurus; Atlantic menhaden, Brevoortia tyran- 

 nus; mullets, Mugil spp.; and flounders, Para/ic/i- 

 thyi^ spp. 



Differences in relative numbers of species in 

 monthly collections were tested with the Wilcoxon 

 signed rank test (Table 4). Seine and rotenone 

 stations were treated separately, and in compari- 

 sons involving Barnards Creek, only the months 

 April to December were used. Among seine sta- 

 tions, Baldhead Creek yielded greater numbers of 

 species than all sites except Hechtic Creek, while 



Table 3. — Total number of individuals and species collected at 

 seine and rotenone sampling sites. Cape Fear River estuary. 

 N.C. 



Samptmg site 



No ol 



individuals 



No ol 

 species 



Sample 

 see 



Baldhead Creek 



Seme 



Rotenone 

 Shellbed Island: 



Seme 

 Dutchman Creek: 



Seme 



Rotenone 

 Walden Creek 



Seme 



Rotenone 

 Hechtic Creek 



Seine 

 Barnards Creek 



Rotenone 



12 



11 



12 



11 



12 



11 



the Baldhead Creek rotenone site produced sig- 

 nificantly more species than other rotenone sta- 

 tions. The upriver sites, Hechtic and Barnards 

 Creeks, were also richer in species than either 

 Dutchman or Walden Creek, but did not yield 

 more species than the station at Shellbed Island. 



The most abundant species ( collectively compos- 

 ing O.S*^ or more of the total number of individu- 

 als) were essentially similar among stations (Ta- 

 ble 5), differing only in their order of abundance. 

 For example, Leiostom us xanthurus; mummichog, 

 Fundulus hcteroclitus; and striped mullet, Mugil 

 cephalus, were ubiquitous, and Brevoortia tyran- 

 nus\ white mullet, M. curema; and Atlantic silver- 

 side, Menidia rnenidia, nearly so. Other abundant 

 species seemed more closely associated with 

 .specific habitats; the striped killifish, F. majalis, 

 for example, was restricted mainly to high salinity 

 areas, while the Atlantic croaker, Micropogonias 

 undulatus. and hogchoker, Trinectes maculatus, 

 were collected more frequently in brackish water 

 with bottoms high in organic matter. It should be 

 emphasized that seine and rotenone methods used 

 here differed somewhat with respect to gear ef- 

 ficiency and selectivity (Weinstein and Davis in 

 prep.) and, in addition, invertebrates such as 

 brown shrimp, Penaeus aztecus, and blue crab, 

 Callinectes sapidus, were not considered to be 

 sampled quantitatively with rotenone. These 

 species, however, were common at all seine sites 

 except Shellbed Island. 



The effects of the extreme cold in January and 

 February 1977 along the eastern seaboard were 

 reflected in the data with severely reduced catches 

 of organisms in these months. Although catches 

 might have been expected to be higher at this time 

 of year, ice covered the headwaters of several 

 marsh creeks, and water temperatures in the shal- 

 lows hovered between 0' and 2' C. These tempera- 



T.ABLE 4. — Species richness comparisons among seine and 

 rotenone stations. Cape Fear River estuary, N.C. The test statis- 

 tic IS the Wilcoxon signed rank test, * = significant at a = 0.05; 

 ns = not significant. 



Seme 

 station 



Baldhead Shellbed Dutchman Walden 

 Creek Island Creek Creek 



Hechtic 

 Creek 



Baldhead Creek 

 Shellbed Island 

 Dutchman Creek 

 Walden Creek 

 Hechtic Creek 



344 



