Densities and biomass of macrobiota within the associations were 

 determined using randomly placed sample quadrats. Quadrats used in 

 all associations except those in the upper intertidal were of 0.25- 

 square meter size. Duplicate 0.01-square meter quadrats were used in 

 the upper zones. Numbers drawn from a random numbers table, equating 

 to vertical and horizontal distances from permanent points on the is- 

 land, were used in locating the sampling quadrats. 



Divers measured the distances with an underwater steel tape and 

 then, looking away from the bottom, released the quadrat about 1 

 meter above the bottom. This minimized sampling bias. If the 

 quadrat came to lie in or over a crevice between rocks, it was re- 

 leased a second time. 



The depth of the quadrat and time of sampling were recorded and 

 the area within the quadrat was photographed. A record was made of 

 the densities of each species within the quadrat (numbers or percent 

 coverage) . Large organisms less than 50 percent enclosed within the 

 quadrat boiindaries were not recorded. All detachable macrobiota were 

 removed and placed in labeled plastic bags for subsequent biomass 

 measurement. The contents of each collecting bag were wet-blotted 

 and weighed on a triple-beam balance (precision approximately +^0.2 

 gram). Wet weights were recorded for each species. 



To develop biomass data on organisms that are permanently at- 

 tached to the substrate, measured areas were scraped by a diver using 

 a steel chisel and hammer. The removed fragments were collected, 

 using a specially designed slurp gun, fitted with a collecting cham- 

 ber lined with Nitex plankton netting of 333-micrometer mesh size. 

 Contents of the collecting chamber were subsequently weighed as 

 described above. 



All raw data (numbers, percent coverage, and wet weight for each 

 species) were tabulated for each quadrat. Tables were arranged in 

 columnar form with species categories across the top and quadrat 

 numbers along the left-hand margin. Quadrats were grouped according 

 to the association and the sampling locations. Quadrats within tran- 

 sition zones and from apparently similar associations on different 

 sides of the island were separated to facilitate testing against 

 "type" association quadrats (those lying well within the boundaries 

 of distinct associations) . These quadrats were then either combined 

 with or separated from type associations. 



This method of tabulation permitted calculation of summary sta- 

 tistics for all species in each association which in turn facilitated 

 intercomparison of the characteristics of these associations. The 

 following summary statistics were calculated: Frequency (ratio of 

 number of quadrats of occurrence to number of quadrats sampled in 

 each group) ; mean abundance and 95-percent confidence limits for the 

 mean abundance; and average weight per individual (or per 100-square 



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