density; values were highest in September, decreased to March and increased 

 slightly in June. Biomass at JC was higher in September and March, and 

 lower in December and .Tune. The high March 1983 biomass was due in part to 

 the presence of a few large molluscs and was not indicative of a uniform 

 increase in community biomass. Although June densities were high, biomass 

 was lower than other quarters since most of the organisms were small 

 oligochaetes . Seasonal fluctuations in biomass at WP followed those of 

 density, with highest values occurring in December. 



Community Dominance 



Intertidal communities during 1983 were numerically dominated by 

 annelids and rhynchocoels; only three arthropod and one mollusc species 

 were among the dominants at the three stations sampled (Table 3) . At all 

 stations, only a few species accounted for the majority of the individuals, 

 with the ten most abundant taxa accounting for 99.2, 98.8 and 98.7% of the 

 total organisms collected at ON, JC and WP , respectively. Oligochaetes 

 were the only organisms among the top ten dominants at all stations. Both 

 GN and WP communities Included Paraonis f ul gens , rhynchocoels, 

 oligochaetes, and Haploscoloplos f ragilis among their dominants. 



At GN , Paraonis fulgens was most abundant (11/core) accounting for 

 37.5% of the total organisms collected (Table 3). Rhynchocoels were second 

 in abundance at this station and accounted for 23.3% of the total. 

 Oligochaetes, Scolecolepides viridis , Haploscoloplos spp . (juveniles), and 

 Capitella spp. were collected in similar abundances and accounted for 6.3 

 to 9.2% of the totals. At JC, oligochaetes overwhelmingly dominated 

 (249/core) accounting for 81% of the individuals. Scolecolepides viridis 

 was the only other organism to occur in substantial numbers at this 

 station. At WP , rhynchocoels (9/core) , Haploscoloplo s fragilis (6/core) , 

 and oligochaetes (3/core) were the most abundant taxa, accounting for 39.6, 

 25.6, and 11.9% of the total organisms collected. 



Although the 1983 sampling program continued to identify year to year 

 changes in the position of taxa among the dominants, there have been no 

 long-term shifts in the composition at any of the intertidal monitoring 

 stations . 



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