FISHERY BULLETIN: VOL. 76, NO. 1 



Table 2.— (Continued). 



20 



Polychaete species 



Syllidae; 



Brania clavata (Clapar^de) 



Exogone dispar Webster 



£ hebes (Webster and Benedict) 



E verugera (Claparede) 



Parapionosyllis longicirrata (Webster and 

 Benedict) 10 



Proceraea cornuta (Agassiz) 220 



Sphaerosyll(S erinaceus Claparede 



S hyslrix Claparede 



Streptosyllis arenae Webster and Benedict 



S varlans Webster and Benedict 



Syllis cornuta Rattike 



S gracilis Grube 



Syltides sp 

 Terebellidae: 



Amphitrite ornata (Leidy) 



Pista cristata (OF Mijller) 



P. palmata (Verrill) 



Poly cirrus eximius (Leidy) 190 



20 



30 



50 



40 



1,140 



40 



10 



40 

 20 



40 



830 



25 



850 



1,425 



1,125 



175 



50 



125 



175 



75 



50 



100 



100 



estuary contained larger densities of carnivores 

 and omnivores. One station on the most southerly 

 transect in this salinity range had the coarest sed- 

 iment found to this point (M 1.00) and the most 

 diverse fauna. Eleven species were present repre- 

 senting both sedentary (e.g., H. fUiformis, Streh- 

 lospio benedicti, and Asabellides oculata) and er- 

 rant types (e.g., Glycera dibranchiata, G. 

 americana, Eteone heteropoda, and E. longa). 

 Since all species mentioned occurred at both 

 higher and lower salinities, species richness may 

 be a response to the sediment type. 



Fifty-one species were collected in the estuary in 

 salinities >25%o. The six species found in the 

 upper bay all occurred here. Nineteen species col- 

 lected in the midbay area were also found in the 

 high-salinity samples. Twenty-six additional 

 species found in the lower estuary were not found 

 in salinities <25%o. They were equally divided 

 between sedentary and errant types. The seden- 

 tary deposit-feeding species are mainly sand- 

 dweller types, such as Paradoneis lyra, Scolelepis 

 squamata, and Spio setosa, while the errant 

 species consisted of phyllodocids, nephtyids, and 

 polynoids. 



Delaware Bay Temporal Studies 



To examine more closely the temporal changes 

 in assemblages in different Delaware Bay sedi- 

 ments, a program of quarterly sampling was un- 

 dertaken in Area C ( Figure 1 ) . Three sandy shoals, 

 three muddy sand bottoms, a polymodal sediment, 

 and a calcareous serpulid assemblage were the 

 selected sites ( Watling and Maurer see footnote 6). 

 At all of the stations the salinity was >25%o. In 

 addition to the quarterly samples, 20 replicate 



216 



grabs and 20 replicate dredge hauls were taken at 

 a station representing each substrate to obtain a 

 more accurate count of species abundances. 



SANDY SHOALS.— Two of the shoal stations 

 were located in the middle of the bay on Brown 

 Shoal and Lower Middle Shoal. Sediments were 

 medium-well sorted (M 1.9-2. 9c/), cr = 0.30(f)) sand 

 constantly subjected to strong tidal currents. The 

 fauna was restricted to a few species of polychaetes 

 throughout the year: Nephtys picta, N. bucera, 

 Magelona sp. 2 (near riojai), and Spiophanes bom- 

 byx. The species were always present in densities 

 of <10 individuals/0.1 m^. The third shoal station 

 on Old Bare Shoal was slightly different in faunal 

 and sedimentary characteristics. The sediment 

 was finer ( M 2.8-2.9(f), a = 0.30</)), with sorting the 

 same as the other shoals. The polychaete fauna 

 was dominated throughout the year by Glycera 

 capitata, G. dibranchiata, Scoloplos robustus, S. 

 fragilis, and Spiophanes bombyx. The 20 replicate 

 grabs taken at this station in the summer indi- 

 cated that G. capitata had a density of 4.1 

 individuals/0.1 m^. Glycera dibranchiata occurred 

 in a density of 1.8/0.1 m^. The dredge hauls indi- 

 cated the same dominant species with the addition 

 o{ Asabellides oculata. 



MUDDY SAND BOTTOM.— The three muddy 

 sand stations were similar in sediment composi- 

 tion (M 3.2-4.7(/), cr = 1.50(/)) and also in 

 polychaete distribution. One of the stations was 

 dominated by the bivalve, Nucula proxima , to the 

 exclusion of other species. Asabellides oculata and 

 Capitella capitata were the dominant polychaetes 

 according to the quarterly studies; however, their 

 densities were very low all year. The 20 grab sam- 



