flats. Growth is rapid from October through June and reduced in summer. 

 Total annual growth is about double that of northern hard clams. The 

 greatest enemy is blue crab, which consumes vast numbers of juveniles. 

 Other predators are worms, whelks, sea stars, octopus, stone crab, and skates. 

 Commercial hard clam production began in Florida about 1880. In 1908 large 

 beds were discovered in Collier and Monroe Counties near the Ten Thousand 

 Islands (Gulf of Mex. ) . Peak production was in 1932, and landings remained 

 high through 1945. Landings declined from 1945 to 1950, gradually increased 

 until 1962, dropped in 1963, but came back strongly in 1964. Availability 

 of markets in the Middle Atlantic states was responsible for this increase. 

 Hard clams are harvested on shallow bars with bullrakes or tongs in water 

 3-4 feet deep. Feasibility of clam farming was established by experiments 

 at Alligator Har. M. mereenaria 1.3-1.7 in long were planted in mud-sand 

 flats in 1 1/2 ft of water at low tide, most on fenced plots, at 10-75 clams 

 per ft^. Growth was poor in crowded areas (.16-. 2 in in 7 mo) but good at 

 concentrations of 10-50 clams/ft2 (.42-. 49 in in 7 mo). Mortality was 

 negligible on fenced plots. All clams on unprotected plots were killed by 

 blue crab and whelks. Recommendations for clam mariculture are given: no 

 pollution, optimum salinity, avoid very hard or very soft substrates, pick 

 a site protected from rough weather, use healthy seed, trial plantings 

 first, use 1/2 inch-long seed to reduce predation, do not plant more than 

 50 clams/f t^ , monitor frequently for predators and poachers, plant in shallow 

 water for easy harvesting, bring product to market as quickly and cheaply as 

 possible for maximum profit. Surf clam, marsh clam, and coquina clam are 

 discussed briefly. - J.L.M. 



622 



Gabbott, P. A. 1975. 



Storage cycles in marine bivalve molluscs: A hypothesis concerning the 

 relationship between glycogen metabolism and gametogenesis. In Proc. 

 9th Europ. Mar. Biol. Symp. H. Barnes (edj . Aberdeen Univ. Press, 

 Aberdeen, Scotland, p. 191-211. 



Loss of glycogen by bivalves is associated with the reproductive cycle. 

 It is assumed that vitellogenesis takes place at expense of stored 

 glycogen reserves. Conversion of pre-stored glycogen into lipid reserves 

 of developing eggs may be analogous to the glucose-fatty acid cycle in 

 vertebrates. Little is known about interconversion of glucose and 

 glycogen in marine bivalves. A second assumption is that control of 

 glycogen metabolism is essentially the same as in vertebrate systems. 

 If so, it is possible that glycogen metabolism and gametogenesis are 

 controlled by the same regulators. In mammalian liver the main regulators 

 of glycogen metabolism are hormones, mediated by cyclic-AMP and blood 

 glucose. In bivalves the corresponding regulators might be internal 

 neuro-endocrine factors controlling reproductive cycle and level of blood 

 sugar, both of which are influenced by temp, food, and other external 

 factors. Mereenaria mereenaria is not mentioned, but the mechanisms 

 probably are similar to those of the bivalves discussed. - J.L.M. 



623 



Gaddum, J. H., and H. Kwiatkowski . 1938. 



The action of ephedrine. J. Physiol. 94(1): 87-100. 



Ephedrine increases the yield of the substance liberated by nerves so that 

 its properties can be studied more easily. The substance is not 

 noradrenaline, epinine, corbasil, or adrenalone, but may be adrenaline. 

 These actions of ephedrine are attributed to inhibition of amine oxidase. 

 Mereenaria mereenaria is not mentioned. - M.W.S. and J.L.M. 



174 



