COMPARISON OF VARIOUS ALLOMETRIC RELATIONSHIPS IN 

 INTERTIDAL AND SUBTIDAL AMERICAN OYSTERS^ 



Richard F. Dame^ 



ABSTRACT 



The allometric relationships for the possible combinations of whole weight, dry body 

 weight, soft body weight, shell weight, height, and length were computed for intertidal 

 and subtidal South Carolina oysters. All relationships between intertidal and subtidal 

 oysters involving dry body weight were significantly different. The percent moisture 

 in the tissues was 81.1% for subtidal oysters and 83.4% for intertidal oysters and did 

 not vary with size. Height appears to be the most useful parameter for predicting other 

 biomass parameters from field data. 



The American oyster, Crassostrea virginica 

 (Gmelin), is one of the principal biomass com- 

 ponents of many southeastern estuarine ecosys- 

 tems, especially that of the North Inlet Estuary, 

 Georgetown, S.C. (Figure 1). This study of 

 intertidal and subtidal oysters was undertaken 

 for two principal reasons: first, quantitative 

 estimates of various oyster biomass parameters 

 from linear or weight measurements would fa- 

 cilitate secondary productivity studies; second, 

 comparison of the morphology of intertidal and 

 subtidal oysters from a quantitative view would 

 give a more exact meaning to the observed dif- 

 ferences between the two forms. 



Wilbur and Owen (1964) have noted that the 

 size relations between an intact organism and 

 one of its parts or between two of its parts over 

 a wide size range can usually be expressed by an 

 allometric equation or a power function of the 

 following form: 



Y = aX\ 



(1) 



Y is some measure of a part. A' is a measure of 

 the whole body or another part, and a and b are 

 constants. Equation (1) can be expressed in 

 linear form by a logarithmic transformation as: 



^ This research was supported by a Belle W. Baruch 

 Predoctoral Fellowship in Marine Ecology. 



^ Belle W. Baruch Coastal Research Institute, Uni- 

 versity of South Carolina, Columbia, SC 29208. 



log Y = \oga -\- b logX. 



(2) 



The fitted coefficients, a and b, can easily be 

 determined from a set of data using least-squares 

 regression techniques. 



MATERIALS AND METHODS 



On March 21, April 11, May 2, July 25, Oc- 

 tober 3, and December 5, 1970, groups of inter- 

 tidal and subtidal (1 m below mean low water) 

 oysters were collected from the North Inlet area. 

 Individual oysters were separated from clumps 

 and scrubbed with a wire brush to remove foul- 

 ing organisms. The whole live weight of an in- 

 dividual oyster was determined to the nearest 

 0.01 g and varied from 1.70 to 105.50 g. The 

 oysters were then opened, the whole bodies and 

 shells were separated from each other, and each 

 was dried to a constant weight in an oven at 

 60°C. On May 31 and July 25, the weight of 

 each soft body was determined, and the long 

 and short axes of each shell were measured to 

 the nearest 0.1 mm with vernier calipers. 



The statistical treatments used in this study 

 follow the methods of Steel and Torrie (1960), 

 and the computations were carried out on an 

 IBM 7040 computer.'' 



Manuscript accepted March 1972. 



FISHERY BULLETIN: VOL. 70, NO. 4, 1972. 



^ Reference to trade names in this publication does not 

 imply endorsement of commercial products by the Na- 

 tional Marine Fisheries Service. 



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