1285 



Menzel, R. W. 1971. 



Quahog clams and their possible mariculture. Proc. 2nd Ann. Wkshp. World 

 Maricul. Soc. 2: 23-36. 



Quahog clams, genus Mercenaria, have a life history conducive to domestication. 

 Most techniques have been established, and await commercial application. At 

 present state of knowledge it is more practical to grow clams under natural 

 conditions. Specific recommendations for clam mariculture are: 1) a hatchery 

 for reliable seed supply; 2) use hybrid seed, M. mercenaria x M. campechiensis; 

 3) protect against predation; 4) plant at densities of 250 to 500 clams/m 2 ; 

 5) procure proper environmental conditions; and 6) make preliminary trial 

 plantings for evaluation. - J.L.M. 



1286 



Menzel, R. W. 1972. 



The role of genetics in molluscan mariculture. Bull. Am. Malacol. Un. for 

 1971, AMU, 37th Ann. Meeting: 13-15. 



Most of the commercial fishery for hard clam in the United States is for 

 northern quahog, Mercenaria mercenaria. The southern quahog, M. campechiensis , 

 is relatively unimportant because it quickly gapes and dies when removed from 

 the water. Hard clams can be grown commercially in aquaculture if predation 

 can be prevented. Natural recruitment is too erratic, and seed clams for 

 mariculture should be supplied from a hatchery. The two species hybridize 

 readily in the laboratory, and F2 and F3 hybrids have been grown. In Florida 

 it is possible to produce commercial-size northern quahog for the half-shell 

 trade in about 2 years and southern quahog in about 1 year. Growth of hybrids 

 about equals that of southern parent, but keeping quality out of water almost 

 equals that of northern parent. Thus, hybrid clams should be used in 

 mariculture. Concentrated effort is needed by government and industry to 

 apply present knowledge and to intensify research, as has been done with 

 commercial animals and plants on land. - J.L.M. 



1237 



Menzel, Winston. 1972. 



Selection and hybridization in the mariculture of oysters and clams. Proc. 

 3rd. Ann. Workshop - World Mariculture Soc: 3 09-317. 



Next to oysters, quahogs are the most valuable mollusk in the United States. 

 Most are sold in the shell. Northern species, Mercenaria mercenaria, is 

 ideally suited to such use because it has excellent keeping qualities out of 

 water. Southern species, M. campechiensis , quickly gapes and spoils. Native 

 southern species grows almost twice as fast as northern. Fi hybrids grow 

 almost as rapidly, and keeping quality is almost as good as that of northern 

 parent. In Gulf of Mexico waters the northern species, from New York, stops 

 growing in summer. Plans for future experiments are described. - J.L.M. 



1238 



Menzel, R. W. 1972. 



Effects of Man's activities on estuarine fisheries. Underwater Nat. 7(2): 

 19-31. 



Mercenaria mercenaria is not mentioned, but many of the hazards to oysters 

 described could apply equally to hard clam. - J.L.M. 



361 



