Composition and Distribution of Macrobenthic Invertebrate Fauna 



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 PERCENT ORGANIC CARBON 



Figure 153 

 Density and biomass of Cirripedia in relation to sediment organi 



i bon. 



higher level classes, reflecting the trends established by 

 density and biomass (Table 30). 



Copepoda — Only four of our samples contained speci- 

 mens of Copepoda, representing only 0.4% of the total 

 samples. The small size of members of this group in 

 relation to the sampling methods used in this study led 

 to incomplete sampling and the attendant extremely 

 conservative abundance estimates. 



Copepoda represented less than 0.1% of the total 

 macrofaunal biomass and density (Table 3). A total of 

 26 specimens was obtained, yielding a mean density of 

 <0.1/m 2 and a mean biomass of <0.01 g/m 2 (Table 5). 



Samples containing copepods were located in the 

 Southern New England Shelf and Slope subareas. Depth 

 ranges occupied were 50-99 m, 200-499 m and 500- 

 599 m. Copepods were present in three sediment types 

 (sand, sand-silt, and silt-clay), in two temperature range 

 classes (0-3.9° and 12-15.9°C), and in the three or- 

 ganic carbon content classes between 0.01 and 1.49%. 



Values of copepod biomass and density for each envi- 

 ronmental parameter considered in this report may be 

 found in Tables 6—30. 



Cumacea — Cumaceans are marine peracarid crusta- 

 ceans that were widely distributed and well represented 

 in New England waters (Theroux and Schmidt- 

 Gengenbach'). Twenty-three species in 13 genera be- 

 longing to 5 families were identified in our samples 

 from the New England region. Cumaceans were among 

 the subdominant taxa in terms of density, providing 



1.7% of the total number of specimens, but owing to 

 their small size, were much less important in terms of 

 biomass, contributing only 0.1% of the total (Table 3). 



Cumaceans in our collections ranged from 7 to 15 

 mm in length; most were between 8 and 12 mm long. 



Color of our specimens was mostly drab olive to olive 

 brown with a few lighter in color and mottled by dark spots. 



The majority of cumaceans are bottom dwellers that 

 were found buried in sand and mud, filter feeding or 

 browsing organic matter from sand grains. Many ex- 

 hibit diel excursion to the surface or into the water 

 column where they swarm at night. 



Cumaceans occurred in 390 samples (36%. of the 

 total), yielding a total of more than 27,500 specimens 

 (Table 5). Their mean density was 26/m 2 , and mean 

 biomasswas0.ll g/m 2 . 



Geographic Distribution 



Although found throughout the study area, cumaceans 

 showed some interesting patterns of absence, especially 

 in the Gulf of Maine. These distributional patterns 

 reflect the rather restricted sediment particle size pref- 

 erences of cumaceans. They tend to favor sediments of 

 medium to medium-fine particle sizes that are most 

 prevalent in the sand fractions, and shun the coarser 

 (gravels, tills, shelly fractions) and finer (sandy silts, 

 silts and clays) fractions. The Nova Scotian shelf and 

 Gulf of Maine each contain extensive deep basins floored 

 with fine muds, as well as shallower banks paved with 



