CHAPTER 1 



COMMUNITY PROFILE BACKGROUND AND OBJECTIVES; 



DESCRIPTION OF THE COASTAL SETTING 



1.1 INTRODUCTION AND OBJECTIVES 



Oysters occupy a unique status among 

 marine and estuarine invertebrates. As a 

 group, they are the most widely studied 

 and thus best known of all these animals, 

 primarily because of their universal 

 socioeconomic value. Some oyster species 

 are prized for their flavor and high qual- 

 ity protein; some are valued for their 

 pearls. Oyster shell calcium carbonate 

 has long been used as a building material; 

 e.g., "Tabby" houses of oyster shell were 

 once common in coastal Georgia and South 

 Carolina. Oyster shells are fed to chick- 

 ens and are even the source of supplemen- 

 tary calcium in tablets for humans. Oys- 

 ters of various kinds have been cultured 

 for centuries, so, in a sense, some spe- 

 cies qualify as domestic animals. 



Much of the information gathered 

 about oysters has been collected by sci- 

 entists, but a significant amount has been 

 collected by observant laymen, natural- 

 ists, and aquaculturists. The objectives 

 of most of those observations, however, 

 were to learn to grow more oysters in 

 given areas faster and with fewer losses. 

 In the vast oyster literature, there are 

 relatively few "pure" ecological studies 

 that treat the oyster objectively as an 

 ecosystem component. For example, animals 

 associated with oysters are usually 

 referred to as "pest" species, as coyotes 

 are to sheepherders. But just as no orga- 

 nism is autonomous, and all organisms 

 operate within the framework of ecosys- 

 tems, so the oyster's importance extends 

 beyond its socioeconomic value. 



The primary objective of this commu- 

 nity profile is to describe the function 

 of one species of oyster in a portion of 

 its habitat. More specifically, we present 

 a profile of a community associated with, 

 dependent on, and dominated by the Ameri- 

 can or eastern oyster, Crassostrea virgin- 

 ica (Gmelin). The study area comprises 



the coast of the South Atlantic Bight be- 

 tween Cape Fear, North Carolina, and Cape 

 Canaveral, Florida, (Figure la), as dis- 

 cussed in Section 1.2. 



Because the range of the American 

 oyster extends over a wide latitude (from 

 20° N to 54° N), the ecological conditions 

 encountered are diverse and the "oyster 

 community" is not uniform throughout the 

 range (see Section 2.2). The present de- 

 scription applies primarily and specifi- 

 cally to those populations of oysters and 

 associated organisms occurring in the in- 

 tertidal zone in the Southeastern United 

 States. In some portions of its range, 

 particularly in the area being described 

 (which has a large tidal range), the oys- 

 ter builds massive, discrete reefs in the 

 intertidal zone. 



The vertical elevation of intertidal 

 oyster reefs above mean low water is max- 

 imal within the central Georgia coastal 

 zone, where mean tidal amplitude exceeds 

 2 m (2.2 m [7.2 ft] at Sapelo Island, ap- 

 proximately at the center of the South 

 Atlantic Bight). Approximate isopleths or 

 contours of the tidal range along the 

 Atlantic and gulf coasts are indicated in 

 Figure lb. Local areas experience tidal 

 variation because of local hydrologic 

 effects. The most extensive contiguous 

 oyster reefs occur in the South Carolina 

 coastal zone. Oyster reefs diminish in 

 size and significance south of Georgia and 

 north of South Carolina, but there are in- 

 tertidal patch reefs in northeastern 

 Florida and southern North Carolina. In- 

 formation reported in this document is 

 applicable to reefs from Cape Fear, 

 North Carolina, to Cape Canaveral, Flor- 

 ida, except as noted in the text. 



The term oyster reef often is inter- 

 changed loosely with other terms for local 

 estuarine areas inhabited by oysters, 

 including oyster bar, oyster bed, oyster 

 rock, oyster ground, and oyster planting. 



