PROGRESS IN BIOLOGICAL INQUIRIES, 193 2 123 



reaches a very high liijurc. On tlie best g:rounds oysters analyzed in 

 Novombor contained as much as 9 percent of glycojjen (fresh l)asis). 

 After the temperature of the water drops })elow 42° F. oysters begin 

 to hibernate; their meat loses weight, although the shells continue 

 to grow and the total weight increases. 



Analyses of the metal content (iron and copper) indicate a great 

 variabilit.v in the amounts of heavy metals stored by the oysters in 

 difYerent localities and during different seasons. On the basis of the 

 information obtained by the investigators it seems possible to regu- 

 late the metal content of the oyster by proper methods of transpor- 

 tation and cultivation. 



Food of the oyster. — Changes in the chemical composition of the 

 meats are brought about by seasonal changes in the composition of 

 the sea water and in the natural food of oysters. This problem has 

 been studied by Dr. Galtsoff, Mr. Loosanoff, and Mr. Smith, both in 

 the field and in the laboratory. Large numbers of diatoms which 

 constitute the principal food of the oyster were obtained from the 

 oyster bottoms and were raised in pure cultures under controlled 

 conditions. The experiments give considerable information regard- 

 ing the methods of propagation of these important forms and their 

 value as a food of the oyster. It is expected that on the basis of 

 these experiments, a method may be found whereby oyster farms 

 could be supplied with the most suitable food for oysters and unpro- 

 ductive oyster bottoms converted into fertile grounds. 



Japanese oyster. — During the last year, oyster growers made many 

 inci[uiries as to the possible effect on the native stock of the importa- 

 tion of the Japanese oyster. In order to answer this important ques- 

 tion a series of experiments was performed at Woods Hole by Dr. 

 Galtsoff and R. O. Smith. They show^ that the Japanese species, 

 Ostrea gigas, easily interbreeds with the native oyster, Ostrea virginica. 

 It is therefore, obvious that the presence of the Japanese species on 

 the Atlantic coast wall result in the interbreeding of the two oysters. 

 It is, however, impossible at present to state whether the resulting 

 hybrids wall be in any respect better or worse than the native species. 



Control of starfishes. — The work on the control of the starfish by 

 checking its propagation and destroying the young stars by applica- 

 tion of copper sulphate solution was carried out in Buzzards and Nar- 

 ragansett Bays by Louise Palmer. After September 1, on account 

 of lack of funds, the project was discontinued. The Bureau, however, 

 is fully aware of the dangerous situation caused by an extraordinary 

 increase in reproduction of this enemy of the oyster. During the last 

 two summers very heavy spawning of starfishes was observed both in 

 Buzzards and Narragansett Bays. It is expected that the oyster beds 

 in these bodies of water will suffer considerable damages from the 

 depredations of this pest. 



SOUTH ATLANTIC OYSTER STUDIES 



Practical experiments in oyster farming and investigations of con- 

 ditions on the natural oyster beds were conducted from North Carolina 

 to Florida under the supervision of Dr. H. F. Piytherch. Laboratorj^ 

 and field studies of oyster spawning and setting were made at eight 

 representative coastal stations in this section and at the L^nited States 

 Fisheries Laboratory^ at Beaufort, N.C., which serves as headquarters 



