1269 



Menzel, R. W. 1962. 



Shellfish mariculture. Proc. Gulf. Caribb. Fish. Inst., 14th Ann. Sess. 

 Nov. 1961: 195-199. 



Pilot operations to determine whether Mercenaria mercenaria can be raised 

 profitably in Florida waters have shown that, unless clams can be protected 

 from predators, mortality is very high. Experiments underway for 6 months 

 showed encouraging survival and growth. Growth was much more rapid than in 

 northern . waters. In a year, growth rate varies several hundred percent among 

 individual clams, and this offers promise for relatively uniform and rapid 

 growth by selection. Hybrids of northern and southern quahaug grow better 

 than the northern parent. It is concluded that, with refined techniques, 

 costs may be offset by the return from such high-valued seafoods. - J.L.M. 



1270 



Menzel, R. Winston. 1962. 



Seasonal growth of northern and southern quahogs, Mercenaria mercenaria and 

 M. eampechiensis, and their hybrids in Florida. Proc. Natl. Shellf. Assn. 

 53: 111-119. 



Growth was measured for 19 months at Alligator Harbor, Fla. Fastest growth 

 was in spring and fall. Northern quahog had the least overall growth (8 mm 

 clams growing to 41 mm average length) and showed least growth during the 

 hottest period. Southern quahog had the best (growing from 8 mm to 57 mm) 

 and had least growth during the coldest period. Growth of hybrids was 

 intermediate but closer to the southern parent (growing from 8 mm to 52 and 

 55 mm) . Growth of hybrids was better than that of either parent in late 

 spring and early fall. - modified author's abstract - J.L.M. 



1271 



Menzel, R. Winston. 1962. 



Seasonal growth of northern and southern quahaugs and their hybrids. 

 Assoc. SE Biol. Bull. 9(2): 34 (abstract). 



Monthly measurements of growth have been made of the northern quahaug, 

 Mercenaria mercenaria, the southern quahaug, M. eampechiensis , and their 

 reciprocal hybrids for 15 months in Alligator Harbor, Florida. Fastest 

 growth for the 4 groups is in spring and fall. Northern quahaug has the 

 least overall growth and shows least growth during the hottest period of 

 the year. Southern quahaug shows the best overall growth and has the least 

 growth during the coldest period. Growth of hybrids is between the two 

 parents but closer to the southern than to the northern. Growth rate of 

 hybrids is better than either parent in late spring and early fall. - J.L.M. 



1272 



Menzel, R. W. 1963. 



Seasonal growth of the northern quahog, Mercenaria mercenaria and the 

 southern quahog, M. eampechiensis , in Alligator Harbor, Florida. Proc. 

 Natl. Shellf. Assn. 52: 37-46. 



Laboratory-reared Mercenaria mercenaria, mostly under 5 mm shell length, 

 were obtained from Milford, Conn, and planted in boxes of sand covered with 

 wire. M. eampechiensis set in the boxes in spring. Clams were later 

 transplanted and covered with 1/2-inch mesh wire. Measurements were made 

 monthly. The northern species increased from 3 mm to 32.6 mm long in the 

 1st yr , to 4 9.6 mm the 2nd yr, and to 61.5 mm the 3rd yr. Southern clams 

 increased from 16.5 to 54.3 mm the first yr measured, to 74.2 mm the 2nd 

 yr. Although periods of measurement were not the same, M. eampechiensis 

 obviously grew faster. M. mercenaria grew fastest in spring and fall at 

 temps between 15 and 25°C. Growth was less in cold weather and least in 

 summer. M. eampechiensis grew best in spring and fall, was fairly rapid 

 in summer, and slow in winter. Both species grew relatively faster when 

 young. The northern species grew faster than in the area from Me. to N.C., 

 largely because it continued to grow in winter. High turbidity in summer 

 in Alligator Harbor may also have affected growth of M. mercenaria. - J.L.M. 



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