2. Reconnaissance Dives . 



The first subtask involved reconnaissance dives by two diver 

 biologists to make a preliminary survey of major species associations 

 around the island. A limited amount of randomly placed quadrat 

 sampling was done to determine variability in densities of biota. . 



3. Talus Bed Measurements . 



The second subtask was to calculate the volume of the mounds of 

 mollusk shells and shell fragments at the base of the rock revetments 

 around the island (shell "talus") . The dimensions of the talus beds 

 were determined and volumes of shell debris in the beds along each of 

 the four cardinal sides were estimated. 



Dimensions of the shell talus beds were determined by the follow- 

 ing method. Divers swam along each of the cardinal sides of the is- 

 land, noting significant changes in the morphology of the talus bed 

 (i.e., changes in slope or upper and lower margin). Where such 

 changes occurred, the distance between the upper and lower margins 

 was measured using a steel tape. Depths of the upper and lower 

 margins were also recorded to +^0.2 meter. Cross-sectional geometry 

 of the talus bed at each measurement point was determined from the 

 distance from the waterline, water depth, and slope of the rock revet- 

 ment. These cross sections were plotted on base charts for each of 

 the four cardinal sides. The volume of the accumulated shell mate- 

 rial along each side of the island was then estimated. Boundaries of 

 the talus beds were charted. 



4. Seasonal Survey of Permanent Transects . 



The third subtask was to survey permanent transects on the island 

 to determine seasonal variability in densities of macrobiota. Transects, 

 extending from the upper limit of the wave splash zone to the limit of 

 the island's influence on the bottom, were established on the four car- 

 dinal sides of the island (Fig. 3). These transects were surveyed dur- 

 ing each season for 1 year (see App. B for a summary of the data). 



Heavy stakes of steel angle iron marked the upper and lower 

 limits of each transect. A single stake was anchored in the armor 

 rock above the splash zone on each side of the island, marking the 

 upper limit of the transect. Three identical stakes were driven into 

 the natural bottom sediment near the seaward margin of the talus bed, 

 and were alined parallel to each side. The three stakes were con- 

 nected with 0.6- centimeter-diameter polyethylene line and floats were 

 attached to each stake to facilitate locating them during conditions 

 of restricted visibility (Fig. 4). 



A nylon line marked off in 1 -meter increments, was used as the 

 transect line. During each survey, one end of the transect line was 



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