62 



NOAA Technical Report NMFS 140 



NUMBER WEIGHT 



MEAN PERCENTAGE TEMPERATURE PERCENTAGE MEAN 



ALL TAXA COMPOSITION RANGE COMPOSITION ALL TAXA 



432 



1.098 



2.386 



1.746 



1.934 



4,038 



to 3.9 



4 to 7.9 



8 to 11.9 



12 to 15.9 



16 to 19.9 



20 to 23.9 



EXPLANATION 



□ 



CRUSTACEA 



ECHINO0EBMATA 



□ 



46 



88 



231 



318 



467 



422 



Figure 25 



Quantitative composition of the total macrobenthic invertebrate fauna in 

 relation to the annual range in bottom water temperature. Mean number 

 of individuals and mean wet weight, per square meter of bottom area, and 

 percentage composition, by density and biomass, for the major taxonomic 

 groups are shown. 



A pronounced decrease in abundance of sponges in 

 each geographic region from Nova Scotia southwest- 

 ward to Southern New England was evident in weight, 

 number, and frequency of occurrence (Tables 5-10; 

 Fig. 28). Porifera were particularly scarce in the South- 

 ern New England subarea. 



Bathymetric Distribution 



Porifera were moderately common to scarce on the 

 continental shelf and upper continental slope (to 500 

 in), 1 to 3 individuals/m , and were very scarce (<0.4/ 

 m 2 ) at depths >500 m (Table 1 1; Fig. 29). Biomass also 

 was moderate on the continental shelf and upper slope 

 and small on the middle and lower slope and continen- 



