Composition and Distribution of Macrobcnthic Invertebrate Fauna 



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Figure 24 



Green silty sand and gravel bottom at 450 m depth on the southern New England continental 

 slope. Gravel ranged to 2 cm. The tubes of two soda straw worms (Hyalhwecia tubicola) are visible at 

 left edge of the frame, and the tracks created by their movements are also visible. The silty nature 

 of the bottom is evident by the cloud created by the camera tripping weight at right-center. 

 Photograph taken at station 1325, located at lat. 39°20' N., long. 72°09' W. 



Porifera were most common in the Nova Scotia re- 

 gion and along the coast of Maine. These areas have 

 stable substrates and moderate to strong water currents. 



Colorful species were rare, limited mainly to the red 

 Microciona. Shades of browns and grays were the most 

 common colors. The colorless Hexactinellida (glass 

 sponges) occurred only in deep water, greater than 500 m. 



Porifera occurred in 71 samples (7% of total); density 

 averaged 1.5/nr and biomass averaged 2.2 g/nr (Table 5). 



Geograph ic Distrib ution 



Porifera were clearly more abundant off Nova Scotia 

 and in the Gulf of Maine than to the south and west 

 (Fig. 27). They were common along the western coast 

 of Nova Scotia, particularly in the mouth of the Bay of 

 Fundy, along the Maine coast, and in the eastern Gulf 

 of Maine. The scarcity of sponges on the continental 

 shelf between central Georges Bank and New Jersey was 

 especially noteworthy. 



