To determine growth, Ascophyllum tip length was measured at three 

 stations (Giants Neck, White Point, and Fox Island). Fifty plants at 

 each of the three sites were tagged; a numbered plastic tag was fastened 

 to the base of the plant, and five apices were marked with small plastic 

 cable ties and colored plastic tape. Measurements were made from the 

 top of the most recently formed bladder to the apex, or apices if 

 branching had occurred. In April and May 1982, the bladders had not yet 

 developed sufficiently to be securely tagged; measurements were made of 

 five tips on each of 50 randomly chosen plants. Monthly measurements of 

 tagged plants began in June. Lost tags were not replaced, and the 

 pattern of loss was iised to estimate Ascophyllum mortality. Loss of the 

 entire plant was assumed when the base tag and tip tags were missiag; 

 tip survival was measured both in terms of remaining tapes, and 

 remaining tips with viable apices. The rationale for this distinction 

 will be dealt with in the Ascophyllum growth section. 



Data Analysis 



Relative abundances of intertidal organisms were calculated on the 

 basis of percent substratum covered by each taxon. Unoccupied substrata 

 were classed as free space. 



Similarity of the communities was determined by a percent 

 standardized form of the Bray-Curtis coefficient (Sanders 1960) , 

 calculated as: p 



^, - }j m.'n (i.., P 

 jk . II IK 



where Pij is the percent of species i at station j , Pik is the percent 

 for station k, and n is the number of species in common. The same 

 clustering algorithm was applied to the resulting similarity matrix as 

 was outlined in the Benthic Infaunal section of this report. The 

 calculations were performed on raw percentages. 



