TABLES 



No. Page 



1. Pecks of clams removed from each quarter 19h9 and 1950 by 

 bullraking and dredging . 9 



2. Breakage of commercial-sized claras by bullraking and by dredging 



in test plot 12 



3^ Length frequencies of clams remaining in 500 square feet of 



bottom after raking and dredging I9I4.9 and 19^0; control was unfished . 27 



U. Length frequencies of clams removed by raking and dredging 



from 500 square feet of bottom 19U9 and 1950 30 



5. Number of clams per bottom sample from all series I9U9 and 1950 . 33 



6. Transformation o f number of clams per bo ttom sample grouped in 

 classes of 2 by /midpoint of class 3/0 36 



7. Tests for estimating sampling reliability of 19^0 cla mshell 



bucket samples computed using values transformed by /x + 3/^ . . UO 



8. Length frequencies of all clams in two series of 50 clamshell 

 bucket samples each in the control area, October and November, 1, 

 1950, and November 8, 19^0 Ul 



FIGURES 



1. Narragansett Bay, R. I., showing location of hard clam fishery 



and test plot 2 



2. Bullrakes are used by about half of Rhode Island's 1,U00 "hand" 

 diggers h 



3. Hard-shell clam dredges are operated from 3O-I4.5 foot power 



boats in the southern half of the Sakonnet River 6 



U. Size distribution of 6U0 clams from test plot May 6, 19U9 - 



before experiment. Data smoothed by moving average of 3's ... 7 



5. Plan of dredging vs. raking test plot 8 



6. Clamshell bucket samples five square feet of bottom 11 



7. Size composition of catch by bullraking and dreding in relation 

 to available population. Catch efficiency ratio of 1.0 indi- 

 cates maximum efficiency of the gear lo 



8. Size distribution of clams in 500 square feet of bottom from 

 dredged area before and after 19h9 fishing. Difference betvreen 

 dotted and solid lines shows removal by dredge fishery. Popula- 

 tion after fishing is based on 28 clamshell bucket samples taken 

 Nov. 18, I9U9, increased to 100 for comparison with Figure 9. 



Data smoothed by moving average of 3's 17 



