50 



70 90 no 130 



Length In Millimeters 



ISO 



Figure 7, — Size distribution of Nantucket Sound liard clams 

 smoothed by a moving average of tliree 



these sediments on deck revealed many 

 characteristically snnall moUusks such as 

 Yoldia limatula and Nassarius trivittatus, but no 

 small hard clams. Razor clams, Ensis directus, 

 2 to 4 inches long were also abundant. The 

 presence of these other small mollusks 

 indicates that small hard clams could have 

 been retained had they been present in 

 the sediments. 



These data indicate that wide variations in 

 meat yields can occur when clams are 

 taken from various places in the Sound. 

 Differences as great as 7 percent were 

 obtained when connparisons of meat yields 

 per 80-pound bushel were made for samples 

 from widely separated areas. But even 

 greater differences were apparent when 

 comparing meat weights alone. For ex- 

 ample, 40.4 percent more meat was obtained 

 at station 5 than at station 4. The possi- 

 bility that meat yields might be charac- 

 teristic of certain areas could not be de- 

 termined because of lack of sufficient data. 



Table 2. — Meat yields per 80-pound bushel 

 of clams, 1958 



To check further for the presence of 

 small hard clams we took 196 samples with 

 the clam-shell bucket in two places (fig. 5) 

 in the Horseshoe Shoal-Monomoy Point 

 area. No small clams were taken in these 

 samples, although IZ large ones were 

 caught. Ten other species of mollusks, 

 most of which were less than an inch 

 long, were found. Again these snnall mol- 

 lusks indicate that small hard clams would 

 have been caught had they been present in 

 the sediments. 



OBSERVATIONS ON MEAT YIELD 



Measurements of meat yield from eight 

 samples of clams were obtained during the 

 survey. The locations of these samples ap- 

 pear in figure 5 and the meat -yield data 

 are presented in table 2. While shucking 

 out a sample, the meats were allowed to 

 drain in a colander. Then the meats were 

 placed in sealed jars and weighed in port. 



DISCUSSION 



The Nantucket Sound hard clam survey 

 disclosed three innportant facts. First, the 

 population densities of hard clams, even 

 in the areas being commercially fished, 

 were very low. Second, there were no hard 

 clams smaller than 60 mm. in length. 

 Third, no new hard clam areas of conn- 

 mercial abundance were discovered. 



Low hard clams concentrations were 

 expected on the basis of discussions with 

 people having knowledge of the area, but 

 the extremely low densities found by the 

 survey were somewhat surprising. The 

 area supports a commercial fishery only 

 because of the efficiency of the jet dredge. 



The extremely low population densities 

 encountered in Nantucket Sound will be 

 better comprehended by comparison with 

 those from surveys made elsewhere along 

 the Atlantic coast. Most of the other surveys 



