FISHERY BULLETIN: VOL. 87. NO. 1 



7^28' 



71'26' 



Figure 1.— Areas dredged (black areas) for crabs in Pettaquamscutt River, RI, 1955-57. Shoal bars were exten- 

 sive near dredging areas. The islands were marshy (stippled areas) and were contiguous with mainland areas (dashed 

 lines). An insert (bottom, right comer) shows Pettaquamscutt River in relation to the West Passage to Narragansett 

 Bay. 



sex of each crab were determined, and the carapace 

 width (in mm) of each crab was measured with ver- 

 nier calipers. Stomachs were then removed and 

 preserved in 10% formalin. Food items were iden- 

 tified using a stereoscopic microscope, and the fre- 

 quency of occurrence of each item was recorded. For 

 some stomachs it was possible to count individual 

 bivalves. 



Descriptions of the amount of food in the stomachs 

 were as follows: 1 ) full stomachs, containing tissues 

 and hard parts of foods, 2) nearly empty stomachs, 

 containing only a few fragments of hard parts of 

 foods, and 3) empty stomachs. The stomachs in the 

 first category were tabulated as the percentage of 

 all crabs in a sample, and those in the second cate- 

 gory as a percentage of the stomachs containing 



198 



