FISHERY BULLETIN: VOL. 87, NO. 1 



20 40 60 80 100 120 140 160 



CARAPACE WIDTH (mm) 



Figure 2.— Frequency distribution of carapace widths of five crab species collected from Pettaquamscutt River, RI, 



1955-57. 



and 59 mm. Lady crabs ranged from 27 to 83 mm 

 CW, with most <50 mm. Spider crabs ranged 

 from 13 to 93 mm and mud crabs from 3 to 12 

 mm. 



Blue Crab 



Animal foods were found in 91% of the blue crab 

 stomachs and plant foods in 19% (Table 2). This in- 

 dicated a predominantly carnivorous food habit. Of 

 the animal foods, arthropods were more frequently 

 (68%) encountered than moUusks (55%) or annelids 

 (17%). Crabs (40%) and small crustaceans (33%) 

 eaten by blue crabs were examined. Pelecypods 

 (49%) were found more often than gastropods (12%), 

 while the gem clam, Gemma gemma, (28%) and blue 

 mussel (16%) occurred most often. The number of 



gem clams in 43 stomachs ranged from 2 to 821 

 (with an average of 66.8 per stomach). Few whole 

 mussels had been eaten (<4 per stomach), but most 

 of them occurred as shell fragments. Other pelecy- 

 pods found infrequently were soft-shelled and hard- 

 shelled clams, and glossy shell (possibly Te.llina sp.) 

 and ribbed shell (possibly Argopeden sp.) fragments. 

 Gastropods were found infrequently and, except for 

 Hydrobia sp., were incomplete, broken shells or 

 operculi. The jaws of Nereis sp. found in 13% of the 

 stomachs indicated that it was the most frequently 

 eaten annelid. Fish remains were found in 18% of 

 the stomachs. Of the plant foods, Spartina occurred 

 in 12% of the stomachs and algae in 8%. Uniden- 

 tified tissues were in 67% of the stomachs. Although 

 75% of the blue crab stomachs contained food, 24% 

 of these were nearly empty. 



200 



