Nasby Lucas et al Use of submersible Iransect data and multibeam sonar imagery for hiabital assessment 



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Figure 5 



Habitat patch boundaries and transects segmented by bottom type overlaid on both bathymetric and baclt- 

 scatter sonar images. Habitat patches are labeled A-H. The bottom-type observations were grouped into 

 three predominant habitats: mud. mixed substrate, and rock ridge. 



large-scale rolling ridges with less small-scale relief. Low- 

 backscatter values were associated with mud bottoms, 

 which have characteristically low reflectivity. 



Eight regional patch boundaries were drawn based on 

 areas of relative homogeneous seafloor sonic character- 

 istics around the six stations surveyed by submersible 

 (Fig. 5). These patches (labeled A-H) ranged from 1.8 km- 

 (patch B) to 38.9 km-^ (patch C) (Table 1). Patch boundaries 

 for A, C, and F were drawn around areas of mid-backscat- 



ter reflectivity and high relief indicated by the bathymet- 

 ric data, and were located in relatively shallow areas of 

 the bank (75-125 m). Patch boundaries for D and H were 

 drawn around mud areas located off the edge of the bank, 

 which exhibited low-backscatter values, low relief on the 

 bathymetric data, and were located in deeper waters ( 150- 

 300 m). Patch boundaries for B, E, and G were drawn 

 around areas of high backscatter and were present in 

 intermediate depths ( 100-150 m). 



