504 



Dow, Robert L., and Dana E. Wallace. 1954. 



Shellfish management. Dept. Sea Shore Fish., Augusta, Me., 3 p. (mimeo.) 



It is highly desirable to limit frequency of clam digging in any area. 

 Commercial digging with a clam hoe ultimately destroys at least 50% of clams 

 remaining on the flats by shell breakage and smothering of sub-legal clams 

 or exposure to predation. Many clam grounds in Maine have relatively few 

 small clams. Without controls area after area will go out of commercial 

 production, and digging will be limited to areas in which small clams have 

 survived to commercial size. A recent experiment showed that yields could 

 be improved substantially by complete removal of marketable clams in an area, 

 followed by closure to protect further natural sets. Digging should not 

 begin when the first clams reach marketable size. An initial management 

 program is proposed which will begin with a public informational meeting and 

 formation of a small industry advisory committee. Surveys would evaluate 

 clam populations, sizes, growth, predators, and competitors. Results of 

 surveys would be presented and discussed at public meetings. Rotation 

 schedules would be established for open and closed grounds, and periodic 

 surveys would evaluate the condition of the stocks . Experiments would be 

 carried on under various environmental conditions to evaluate the economic 

 feasibility of predator control. Cooperative programs between adjacent towns 

 would be encouraged. Local economic conditions and employment would be 

 considered in making decisions. (Abstracter's note: In New England, clam 

 means Mya arenaria, the soft clam. Mercenaria mercenaria is called quahog. 

 The plan outlined probably would work equally well with hard clam.) - J.L.M. 



505 



Dow, Robert L., and Dana E. Wallace. 1955. 



Commercial scale shellfish management experiments in Maine. 5th Conf. on 

 Clam Research, 4 p. (mimeo.) 



Experiments were conducted with Venus (Mercenaria) mercenaria and Mya arenaria. 

 The project was cooperative with towns and commercial diggers. Small, slow- 

 growing quahogs were transplanted, growing areas were rotated, harvesting was 

 controlled, and in one area of dense natural set the area was closed, surplus 

 seed was transplanted, and the residual population was harvested under control. 

 Completed experiments with Venus cost $7,548 and produced a commercial product 

 worth $119,369. - J.L.M. 



506 



Dow, Robert L., and Dana E. Wallace. 1955. 



Experiments in the extension of the range of quahogs in Maine waters . Maine 

 Dept. Sea Shore Fish., 3 p. (mimeo.) (retyped Nov. 1967.) 



Experiments included 3 steps: 1) a small experimental plot of 1 to 5 bu, to 

 determine survival and growth; 2) if step 1 was promising,. 10 to 100 bu were 

 planted; 3) if step 2 was a success attempts were made to build up the area 

 by supplemental plantings and natural reproduction. Step 3 was not 

 successful except in the Casco Bay area. Areas of plantings and general 

 results are given in a table. - J.L.M. 



507 



Dow, R. L., and D. E. Wallace. 1955. 



Natural redistribution of a quahog population. Science 122(3171): 641-642. 



Approximately 95 percent of the quahog, Venus mercenaria , fishery in Maine 

 is intertidal and limited to infrequent good sets which occur in limited 

 areas of dense concentration. Shortly after setting, densities as high as 

 25,000 per square foot have been recorded, but mortality rates invariably 

 exceed 90 percent by the end of the second season. Redistribution takes 

 place among smaller size (3 mm in diameter) individuals and does not occur 

 involuntarily among adults. One concentration of quahogs surrounded by 

 barren flats from the 1947 year class was surveyed in Maquoit Bay, Maine 

 before and after the winter of 1950-51 using a plane table and telescopic 



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