9-25 



Each pair of parameters was then correlated (Spearman's rank correlation 

 test, Conover, 1971) . The results of this correlation analysis are 

 shown in Table 9-12. Correlation patterns between these allometric 

 parameters are very similar for Harbor Station and Fort Hale experi- 

 mental groups over all years combined. This is indicated by the fact 

 that all correlation values for these parameters between station are 

 positively significant. It is clear, however, that correlation patterns 

 between years are not similar. If, as Dame suggests, oyster growth is 

 contingent upon local environmental conditions, these results imply that 

 environmental conditions which are relevant to oyster growth were simi- 

 lar at both stations during pre- and post-operational periods. These 

 results temporarily extend the conclusions of the ANOVA. 



Table 9-1 and Figure 9-3 show the patterns of condition 

 indices for control and experimental oysters. Figure 9-3 shows that in 

 all instances dry weight condition indices were lower at Harbor Station 

 than at Fort Hale, and that in all but one instance (1975) condition 

 indices at Harbor Station were lower than in the initial controls. 

 During 1975 initial control oysters had low condition indices, a factor 

 probably reflected in the high initial mortality at both stations. 

 Condition index was first expressed by Grave (1912) as the quality or 

 fatness of oysters measured as the volume of space enclosed by the two 

 valves actually occupied by oyster meat. Hopkins (1949) suggested that 

 the ratio of dry weight of oyster meat (G) x 100 divided by cavity 

 volume (ml) be used as the condition index. Butler (1949) states that 

 condition indices for C. virginica range from 1 to 17 with 10 indicating 

 a marketable oyster. Finally Galtsoff (1964) standardized the measure- 

 ment of cavity volume by displacement of water. 



Few studies have used condition index as a measure of the 

 health of oyster populations. Galtsoff (1964) and Ogle et al . (1977) 

 noted that measurements of condition index have a seasonal pattern which 

 is influenced by time of spawning and amount of food available. Con- 

 dition is generally low after spawning but then builds up as glycogen is 



