'I'lic taxa wlilcli dominated inltrtidal communities have been relatively 

 cdpsi stent , troi^liic structural slrifts have not occurred during our study. 

 Although year to year changes in availability of food may have exerted an 

 influence on the absolute abundance of certain populations, no major shifts 

 in trophic structure have occurred in any intertidal community. 



Long-term Population Densities 



The abundances of the top four infaunal taxa collected at each 

 Millstone intertidal station during 1983 were examined to identify seasonal 

 patterns of abundance and station-specific or area-wide trends in the 

 density that have occurred during the past six years. 



Oligochaetes 



Oligochaetes are small deposit-feeding worms that ranked first in 

 abundance at JC in each of the last six years, with highest density occurring 

 from March 1979 through December 1980 (Fig. 6 A) . At GN and WP, oligochaete 

 abundance has been consistently low throughout the monitoring program 

 (Figs. 6 B,C). Seasonal peaks in density at these sites have occurred at 

 GN during either June or September. At WP , oligochaete abundance from 

 1980-1982 at WP exhibited marked seasonal peaks, exceeding those in prior 

 sampling years, but in 1983 collections, as those obtained prior to 1980, 

 did not exhibit any seasonal peak. 



Scolecolepides viridis 



Scolecolepides viridis is a large burrowing species capable of using 

 a wide range of food resources and occupying a variety of habitats. 

 Scolecolepides ranked second and fourth during 1983 at JC and GN, but was 

 not among the top ten at WP . The density of S^. viridis at JC has been 

 highly seasonal, typically peaking in June, remaining relatively high in 

 September then declining in December and March (Fig. 6 D) . In 1983, 

 however, this species was abundant in each quarter resulting in a higher 

 annual mean abundance and an increase in percent contribution, relative to 

 the previous three years. At GN , major peaks in density generally occur 



15 



