THE OYSTER INDUSTRY OF THE WORLD 



573 



course: it is higher in the oysters of the South Atlantic states and lower in northern 

 oysters. During periods of sexual maturity the manganese content of oyster tissues 

 significantly increases. The metal is stored primarily in the ovaries and is appar- 

 ently associated with the female sexual cycle (Galtsoff, 1942). 



Chemical composition of British and New Zealand oysters does not differ sig- 

 nificantly from that of the American oyster (Table 122). 



Table 122. Chemical Composition of Meat of Atlantic Coast Oyster (Ostrea 



virginica), British Oyster {Ostrea eduUs) and New Zealand Oyster 



(O. commercialis) . 



Atlantic oyster British oyster New Zealand oyster 



Source: Ranson, G., "The Life of the Oyster," Paris, Gallimard, 1943. 



As in the American oyster the chemical composition of the European oyster 

 (O. edulis) does not remain constant, as can be seen from the observation on 

 oysters grown in Norway (Table 123). 



Table 123. Annual Changes in the Chemical Composition of Ostrea edulis in 



Norway 



Maximum 

 Minimum 

 Average 

 for 1936 



Average 

 weight 



g 



14.63 



7.60 



11.30 



Water 



81.9 

 76.0 



78.65 



6.76 



7.77 



2.17 



10.06 



1.34 



Source: Gaarder, T., and Alvasker, E., "Biology and Chemistry of the Oyster in 

 Norwegian Waters," Bergen Museum Yearbook (1941). 



Among the organic constituents of the oyster meat mention should be made of 

 the presence of the glycerophosphoric acid, stigmasterol, and ostreasterol, discov- 

 ered in 1934 in Ostrea virginica by Bergmann (1934). 



From the nutritional point of view oysters present many advantages because of 

 their digestibility and the presence of minerals and vitamins necessary to main- 

 tain health. Determinations made by the United States Fish and Wildlife Service 



