occurred during October. Bryozoans did not attach during the period 

 December through March. The monthly panels also showed a 1-month 

 lag between the maximum average size and maximum number of 

 individuals, indicating that growth was more rapid when competition 

 was less. The cumulative panels also indicate two periods of maximum 

 setting activity (Fig. 12B). The first occurred, as with the monthly 

 panels, during July; however, the second period, indicated by these 

 data, was during November. The trend of the average size curve on 

 the cumulative data plot indicates that bryozoans continued to grow 

 at a relatively constant rate from the time setting first began in June 

 until November. The drop in average size in December is interpreted 

 as further evidence of a new set resulting in a "statistically" smaller 

 average size. 



5. Jingle Shells 



Figure 13 illustrates number and average diameter of jingle 

 shells attaching to the monthly and cumulative panels. The plot of 

 monthly data (Fig. 13A) indicates that jingle shells appeared first 

 during late July or early August in great numbers. Setting continued 

 through October. They did not appear on monthly panels from November 

 through June. The average diameter curves show that jingle shells 

 grew most rapidly during the period of peak attachment. The cumulative 

 panel data (Fig. 13B) indicate, as did the monthly panels, that maximum 

 setting occurred in August. The decrease in number of individuals 

 with increasing exposure time is interpreted as indicating mortality. 

 It appears that jingle shells were gradually replaced or overrun by 

 other forms. Andrews (1953) reports that Anomia (jingle shells) 

 reach full size and die during winter. The size plot shows the growth 

 rate of individuals and indicates an initial increase of size of attaching 

 individuals followed by a period of steady growth of the surviving 

 individuals. 



Jingle shells exhibited a definite preference for the concave side 

 of the panels, as generally 5 to 10 times more individuals were 

 found on the concave side than on the convex. 



6. Tunicate s 



Neither solitary nor colonial tunicates appeared on 1-month 

 panels. One small colony was found on a 2-month panel exposed during 

 March and April. Colonial tunicates in significant numbers first 

 appeared on panels exposed for 3-month periods. Both solitary and 

 colonial forms were noted on panels exposed for 4-month periods, 



16 



