reco.lonizatlon transects; see NUSCo 1980) that had been denuded in April 

 1979, were again scraped and burned in September 1981, to remove a] 1 

 algal and faunal cover. These transects were sampled monthly, as 

 described for the undisturbed transects. 



At the four recolonization stations, a fourth series of exclusion 

 cage studies was begun in December 1982. This experiment was identical 

 in design to those of previous experiments run from April 1979 to May 

 1980 (NUSCo 1981), from May 1980 to September 1981 (NUSCo 1982), and 

 from September 1981 to December 1982 (NUSCo 1983) except for the season 

 in which denuding occurred. 



At each recolonization station, nine exclusion cages were attached 

 to rock, three cages in each tidal zone, i.e., upper, middle, and lower 

 tidal level . The cages (20 x 20 x 5 cm) were constructed from 3 mm 

 stainless steel mesh, and fastened with stainless steel screws to rock 

 surfaces which had been burned and cleared in the same way as had the 

 recolonization transects. Each cage had a gasket-like strip around the 

 bottom edge to discourage entry of predators and grazers. Adjacent to 

 each cage, a 20 x 20 cm control patch was burned and cleared. 



Percent coverage by benthic plants and animals in the experimental 

 and control areas were determined and recorded on a monthly basis. If 

 present, 20 thalli of Fucus vesiculosus in each area were measured to 

 the nearest millimeter. The cages were inspected, and cleaned as 

 necessary. When growth of algae or invertebrates under a cage had 

 reached a point where further growth was inhibited by crowding, the cage 

 was permanently removed. 



R.eplication of both recolonization and exclusion cage studies was 

 undertaken to determine the effect of seasonality on recolonization. 

 Results of the winter (1982) denuding are not yet complete; a subsequent 

 report 'will summarize the entire seasonal cycle. 



Ascophyllum growth studies initiated in April 1979 were continued. 

 This report emphasizes data from plants tagged in 1982, but includes 

 information from plants tagged in previous years. Each group of 

 Ascophyll um plants was followed for an entire year of growth, from new 

 bladder formation in April until the following April. Plants tagged in 

 spring 1983 will be monitored until spring 1984, and the results 

 presented in next year's report. 



