The Laeoneveis culvevi is a eury-tolerant nereid polychaete that is 

 common over a wide range of salinity, from 0.5 to at least 18 parts per 

 thousand (Tenore, 1972; Diaz, 1977). It was widely distributed at Duck, 

 being most abundant in July, possibly as a result of the higher salinity. 

 As with Limnodvilus spp. most of the Laeoneveis aulvevi were juveniles. 

 They were only scattered occurrences of adult individuals from each 

 collection date. Laeoneveis aulvevi was always uniformly distributed with 

 depth and between transects. In January it was the only dominant to occur 

 in the same densities at the nearshore stations (sites 1 to 4) and offshore 

 stations (sites 5 to 8). Its lowest densities occurred in April with about 

 twice as many worms occurring at the offshore stations (Table 24) . 



The Scolecolepides vividis , a spionid polychaete, is a eury-tolerant 

 species with a large salinity range from 0.5 to 25 parts per thousand. It 

 seems to do best in the 5 to 10 parts per thousand range. At Duck it 

 commonly occurred in all collections, but was never really dominant until 

 April and July, when salinities were more than 5 parts per thousand (Table 

 24). Unlike the other annelid dominants when Scolecolepides vividis 

 occurred, the individuals tended to be larger. 



The chironomid larvae are predominantly freshwater fauna, but there are 

 several Genera, including Polypedilum and Cvyptochivonomus , that are eury- 

 tolerant (Roback, 1974). Polypedilum sp. was the dominant species at Duck. 

 Chironomids were common but were never abundant. The greatest densities 

 occurred in April and again in January. 



The Lepidaotylus dysticus , a haustorid amphipod, has the lowest salinity 

 tolerance of the haustorids. It ranges from 0.5 to about 15 parts per 

 thousand. It is also a eury-tolerant species that is widely distributed in 

 low salinity zones of estuaries. At Duck, Lepidaotylus dysticus occurred 

 about as frequently as Limnodvilus spp. and was second in numerical dominance, 

 averaging about 1,025 per square meter for the entire study. The greatest 

 densities occurred in July, followed by November. For all collection dates 

 there were more Lepidaotylus dysticus in the nearshore stations (sites 1 to 4) 

 than the offshore stations (sites 5 to 8) , even in January with a 5- to 10- 

 centimeter ice cover (Table 24). 



The Duck sound fauna formed a single community unit for any one 

 collection date. There was a gradual changing of the community from 

 November to July. While the dominants were the same throughout the study 

 the less common species changed with three species dropping out after November 

 [Lysippides gvayi , Edotea tviloba, leech) and six appearing (Stveblospio 

 benedicti , nemertean, Macoma sp., Leptocheivus plumulosus , Covophium sp. , 

 Cvyptochivonomus sp.). The leech was the only freshwater form to drop out 

 and Cvyptochivonomus sp. was the only freshwater form to be added after 

 November. All other species changes were due to estuarine species. Despite 

 these changes there was still a single community characteristic of the Duck 

 sound in July. The qualitative similarity (Jaccard's coefficient) between 

 November and the other collections was 0.83 in January, 0.72 in April, and 

 0.69 in July, indicating the gradual shift in the nondominant taxa. Cluster 



40 



