FISHERY BULLETIN: VOL. 77. NO- 2 



Table 6. — Length data for year class individuals of selected species. Cape Fear River estuary, N.C.. all station collections combined. 



— = data were not available. 



'Probably mostly Paralichthys lethostigma which was abundant at upriver stations: year class identitied to species after April 

 ^Penaeus sp was collected down to 1 1 mm TL in May probably P aztecus 



Table v. — Relative densities (mean number of individuals/400 m^) for selected species at the peak of postlarval and early juvenile 

 recruitment in the Cape Fear River estuary, N.C. Rotenone collection data are not presented for shrimp, Penaeus spp. 



Baldhead Creek 



Species 



Peak 

 recruitment 

 months Seme Rotenone Seme 



Shellbed 

 Island 



Hechtic Bernards 

 Creek Creek 

 Seme Rotenone Seine Rotenone Seme Rotenone 



Dutchman Creek 



Walden Creek 



Leiostomus xanthurus 

 Brevoortia tyrannus 

 Mugil cephalus 

 M curema 

 Penaeus aztecus 

 P duorarum 

 P setiferus 



Mar -Apr 

 Apr -May 

 Mar -Apr 

 May-June 

 May-June 

 July-Aug. 

 July-Aug. 



1.781 

 110 

 80 

 712 

 113 

 266 

 



3,474 4,520 



16 

 109 



179 



24 



172 



148 







373 



1,788 



979 



257 



2 



60 



439 



970 



2,251 



505 



209 



21 



525 



31 



26 



153 

 24 



73 



3,821 



909 



71 



538 



92 



85 



618 



803 







'April data only 



of brown shrimp occurred at Hechtic and Walden 

 Creeks. Except for a single individual in August, 

 none were collected at Shellbed Island, and 

 catches were also low at the Baldhead Creek site. 

 The presence of shrimp in high densities in Wal- 

 den Creek is of interest since the organic (detrital) 

 content of the substratum is the lowest of any of 

 the Cape Fear stations. Except for one tributary 

 where nearby construction activities have added 

 large quantities of fine sediments, this creek is 

 well scoured almost its entire length. White 

 shrimp (P. setiferus ) were most abundant at Hech- 

 tic and Dutchman Creeks, where the sediment 

 contained considerable quantities of organic mat- 

 ter and were absent from the high salinity stations 

 in Baldhead Creek and Shellbed Island. On the 



other hand, pink shrimp reached maximum abun- 

 dance in Baldhead Creek, while intermediate 

 numbers were also collected at Hechtic Creek. 



Community Patterns 



Numerical classification analysis was employed 

 to detect underlying patterns among marsh nek- 

 ton communities (Figure 4). Two primary station 

 clu.sters were discerned by this procedure, a group 

 consisting of the Baldhead Island sites (i.e., Bald- 

 head Creek seine and rotenone stations and Shell- 

 bed Island) and a second group composed of the 

 Walden and Hechtic Creeks and the Dutchman 

 Creek seine station. The latter cluster was joined 

 bv the Walden and Dutchman Creek rotenone sta- 



348 



