1302 



Merrill, Arthur S., and John W. Ropes. 1967. 



Distribution of southern quahogs off the Middle Atlantic coast. Comm. Fish. 

 Rev. 29(4): 62-64. 



Little was known of the distribution of Mercenaria campeohiensis north of 

 Cape Hatteras. Surveys with hydraulic dredge in 1965 and 1966 extended the 

 range northward to Point Pleasant, N.J. Most southern quahog collected were 

 large because the dredge used was selective. They were larger and more 

 numerous in sand and shell bottom (av. length 105 mm, 9.2 clams/tow) than in 

 sand and silt (av. length 97 mm, 2.8 clams/tow). They were taken from Point 

 Pleasant, N.J. to Oregon Pt., N.C. and were most numerous offshore southeast 

 of Chincoteague Inlet, Va. Fossil records suggest that the species may once 

 have lived farther north, e.g., the Boston Basin. - J.L.M. 



1303 



Merrill/ Arthur S., and Haskell S. Tubiash. 1970. 



Molluscan resources of the Atlantic and Gulf coast of the United States. 

 Proc. Symp. onMollusca, Pt. 3 (Mar. Biol. Assn., India): 925-948. 



About 15 molluscan species are harvested commercially on the east coast of 

 the United States and in Gulf of Mexico, but 5 make up most of the weight and 

 value. Mercenaria mercenaria was third in order of economic importance. 

 Generalized anatomy and physiology of clams is described. Hard clam is 

 distributed from Gulf of St. Lawrence to Gulf of Mexico in relatively 

 sheltered bays, coves, and inlets. Most of the catch was from N.Y. and Va. 

 Great South Bay, Long Island, is an especially prolific source. The southern 

 species, M. campeahiensis, ranges from southern N.J. to Texas, and is almost 

 entirely oceanic. Sexual maturity is attained at one yr of age. Almost all 

 are male. By the 2nd yr half change to female and sex does not change 

 thereafter. Spawning is from mid-June to mid-Aug, when water temp rises 

 above 20°C. Females may release up to 24x10^ eggs at one spawning and 250x10^ 

 in one spawning season. Larvae are about 200 y at setting. Optimal larval 

 development in the laboratory is at 25° to 30°C and salinity 27°/°°. Under 

 these conditions larvae have set in 7 days, but in nature the average time is 

 about 10 to 14 days. Growth is most rapid in warm periods, and clams enter 

 the fishery at 2 to 3 yrs old. Larvae, juveniles, and young adults are 

 affected by environmental conditions, are susceptible to bacterial and fungal 

 infections, and are preyed upon by many predators. Older clams are relatively 

 immune to predation except by man. Clams are dug by hoes, rakes, tongs, and 

 dredges. An average day's catch is three 80-lb bushels in 8 to 9 hrs with 

 manual gear. Patent tongs are used in some areas. Hydraulic dredges can 

 take 25 bu/hr on productive grounds. Smaller sizes, 1 1/2 to 3 inches in 

 diameter, bring the highest prices. - J.L.M. 



1304 



Messier, Arthur A., and Frances C. Garb. 1966. 



Summary of the use of some relaxants on bivalve mollusks. U.S. Pub. Health 

 Serv., Shellfish Sanitation Tech. Rept., Dec. 1966. 



Paper not seen. 



1305 



Metcalf, Theodore G., and William C. Stiles. 1967. 



Survival of enteric viruses in estuary waters and shellfish. In Transmission 

 of Viruses by the Water Route. Gerald Berg (ed.) Interscience Publishers 

 Div., John Wiley & Sons, New York: 439-447. 



Experiments with bivalves were done with oysters, presumably Crassostrea 

 vtrgvnzca, but the findings probably are indicative for Mercenaria mercenaria. 

 Enteric viruses have been demonstrated in shellfishes and in estuarine waters 

 as far as 4 mi from the nearest sewage outlet. Virus survival in oysters 

 appeared to be indefinite until water temp rose above 4°C, then cleansing 



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