--. — 30',_ 



' MAMTUCKC 



10' 



Figure 4.- -Nantucket Sound, showng important shoals and the 5-fathom-depth contour line 



The locations of samples taken with the 

 lined jet dredge, stations where clams 

 were obtained for meat yields, and the two 

 areas sampled with the clam-shell bucket 

 are also shown. 



Figure 6 shows the abundance and dis- 

 tribution of hard clams in the areas of 

 Nantucket Sound surveyed. Isopleths were 

 drawn to include the following population 

 density groups in units of bushels per tow: 

 zero, to represent areas where no clams 

 were caught; 0.1 or less to 0.9, low abund- 

 ance; 1.0 to 4.9, nnoderate abundance; 

 5.0 to 7.9, abundances approaching com- 

 mercial quantities; 8.0 to 10.9, commer- 

 cially fishable quantities; and 11.0 or more, 

 areas of particular commercial importance. 

 The population density contours of figure 

 6 represent the best estimate of the dis- 

 tribution of hard clams based on the sam- 

 ples taken. 



Nantucket Sound was divided into three 

 general areas for convenience of discussion. 



These are well separated from one another 

 by bottom that is probably unsuitable for 

 hard clams. These are (1) the Horseshoe 

 Shoal-Mononnoy Point area, (2) the Tucker - 

 nuck Shoal-Great Point area, and (3) the 

 Edgartown area. 



Horseshoe Shoal-Monomoy Point Area 



The Horseshoe Shoal-Monomoy Point 

 area is the largestandmost important of the 

 three areas of the Sound surveyed, covering 

 approximately 60 square miles. Hard clams 

 were found in this area in very low abund- 

 ance. Even though 84 percent of the 118 

 samples taken here yielded some clams, 

 only 2.5 percent produced 8 or more bushels 

 per tow (table 1). The highest concentration 

 encountered was 13.7 bushels per tow. 



The shallow unnamed shoal which lies 

 in the middle of the relatively deep-water 

 bight enclosed between Horseshoe Shoal 

 and Monomoy Point effectively separates 

 the hard clam producing area into two 



