SHALLOW MARSH HABITATS AS PRIMARY NURSERIES FOR 

 FISHES AND SHELLFISH, CAPE FEAR RIVER, NORTH CAROLINA 



Michael P. Wein'stein' 



ABSTRACT 



Seine and rotenone collections taken during 1977 from the upper reaches of tidal creeks and along the 

 marsh fringe m the vicinity of the Cape Fear River, N.C., indicated that these areas serve as primary 

 nursery habitats for postlarval and juvenile fishes and shellfish- Average densities i number 400m2i for 

 several ocean-spawned species at the peak of postlarval or early juvenile recruitment were high: spot, 

 Leiostomus xanthurus. 3,099; Atlantic menhaden, Brevoortia lyrannus. 839; striped mullet, Mugil 

 cephalus. 711; white mullet, Mugil curema. 52.5; and brown shrimp, Penaeus aztecus. 329. Standing 

 crops for the majority of species studied further indicated that lower productivity per unit area occurred 

 in high salinity marshes closest to the ocean In addition, distribution patterns for several species were 

 significantly correlated with salinity and substrate characteristics or combinations of them and 

 seasonal effects also were evident so that related and potentially competing species were separated 

 temporally 



Community analyses demonstrated that each niar.sh complex was unique; however, overall similar- 

 ity for the most abundant species was high. The diflferences were related to salinity gradients and to the 

 presence of an "edge effect" where marshes closest to the river mouth were species rich due to seasonal 

 invasion by low densities of reef, nearshore, and shelf marine .species. Similarly, freshwater fishes 

 invaded brackish marshes during periods of high river flow 



Patterns of distribution of estuarine species have 

 often been correlated with environmental gra- 

 dients (Remane 1934; Hedgepeth 1957; Gunter 

 1961; Khlebovich 1969; Gainey and Greenberg 

 1977) and have also been described in terms of 

 characteristic estuarine zones: marshes, tidal 

 flats, sounds, bays, and channels. Within these 

 areas, organisms are frequently associated with 

 specific habitats; for example, the marshes can be 

 divided into the high marsh and tidal creeks, the 

 latter characterized by soft muds at their head- 

 waters and by more scoured areas downstream. 

 Several properties of the water column also vary 

 in these creeks, being generally more stable near 

 the creek mouth (Hackney et al. 1976), and the 

 presence of food organisms is often correlated with 

 sediment properties so that predators may fre- 

 quent one area more than another (deSylva 1975). 

 On the basis of individual tolerances, some species 

 will frequent habitats under a wide range of condi- 

 tions, while others will be more restricted in their 

 distribution. These tolerances may change with 

 the age of the individual so that a given species 

 may be a member of several different communities 

 during its life cycle. 



'Lawler, Matusky & Skelly Engineers, One Blue Hill Plaza, 

 Pearl River, N.Y.; present address: Department of Biology, Vir- 

 ginia Commonwealth University, Richmond. VA 23284. 



When the nursery role of estuaries is considered 

 in this framework, it becomes evident that infor- 

 mation is lacking on age-specific utilization of es- 

 tuarine zones. Few investigators have studied the 

 primary nursery areas where the youngest mem- 

 bers of many ocean-spawned species first take up 

 residence (Herke 1971; Parker 1971; Purvis-), In 

 one such area, the tidal salt marshes, comprehen- 

 sive sampling efforts have demonstrated that a 

 temporal succession takes place with many spe- 

 cies residing in the upper reaches of tidal creeks 

 during their earliest days and then moving gradu- 

 ally downstream as they grow (Herke 1971; 

 Dunham 1972; Purvis see footnote 2). A similar 

 successional pattern occurs in the upper reaches of 

 the Chesapeake Bay (Haven 1957; McHugh 1967; 

 Chao and Musick 1977 1 and in open bay waters 

 near the heads of estuaries in South Carolina 

 (Bearden 1964), Louisiana (Thomas and Loesch 

 1970), and Florida (Hansen 1970). 



The present study details the composition of the 

 nekton community of several shallow marsh areas, 

 including tidal creeks and marshes adjacent to the 

 river shoals. Consideration is given to the role of 

 these habitats as primary nurseries, and patterns 



Manuscript accepted January 1979 

 FISHERY BULLETIN: VOL, 77, NO. 2, 1979. 



^Purvis. C, 1976, Nursery area survey of Northern Pamlico 

 Sound and tributanes, Div. Mar. Fish, Rep. (prepared for U.S. 

 Dep. Commer.. NOAA, Natl. Mar. Fish. Serv.l, 62 p. 



339 



