PROGRESS IN BIOLOGICAL INQUIRIES, 1986 45 
The decline of the York River oysters during the last 20 years 
has resulted in a serious loss to many depending upon this industry 
for a livelihood. Inasmuch as no similar changes in quality have 
been noted in the oysters of nearby rivers, it may be assumed that the 
decline of the York River oysters is the result of local conditions. 
To determine whether the complaints of oystermen were justified, 
healthy oysters were obtained from the James River and planted at 
seven stations in the York River for observation on the physical and 
chemical changes occurring. Oysters taken from areas of the York 
River where the oysters are poor were transplanted to other locali- 
ties, and changes in their condition were carefully followed. The 
condition of the oysters found in the York River was observed 
throughout the year. 
The oysters in the York River showed a gradation of condition. 
Those in the river below Claybank were healthy and marketable 
while these above that point were noticeably poor and unfit for 
market. The meats were watery and transparent and the majority 
of the oysters had spots of green on the body. The taste of these 
oysters was acrid and disagreeable. Food was found in the stomachs 
but apparently this material was not properly assimilated for the 
oysters had not fattened and were low in glycogen content. Shell 
growth was observed but there was no thickening and strengthening 
of the shel! by calcareous material necessary for handling and 
shucking. ‘The gonad development was slow and the spawning light. 
The oysters taken from the Piankatank River, and used for com- 
parison with those of the York River, presented an entirely different 
picture. These were healthy, showed a high glycogen content, and 
possessed strong shells. 
Observations parallel to those made on the York River oysters were 
made on the James River experimental oysters planted in the York 
River. Those introduced into the lower river maintained a healthy 
growth, while those planted in the upper river became weakened and 
poor. Green spots appeared on the body and the meats became watery 
and emaciated. Jour months after transplanting the healthy James 
River oysters to various sections of the York River they assayed almost 
the same percent of glycogen as the native oysters; 1. e., the upper 
York planted oysters analyzed low and the lower York planted oysters 
analyzed high in glycogen. 
A group of oysters was taken from a section of the York River 
where conditions were bad and transplanted to other waters. At the 
time of transplanting these oysters were unmarketable, being watery, 
emaciated, and containing spots of green material on their bodies. 
The shells were rotted and handling was almost impossible. In March 
1936 several bushels of these oysters were transplanted to the lower 
York River and upper Piankatank River to see if replanting in an 
environment entirely apart from the harmful influence would better 
their condition. The results were very striking. The shells were im- 
proved, the meats “fattened,” and the green disappeared. Eleven 
months after transplanting the glycogen content was double that of 
oysters remaining on the original beds. 
One of the few remaining oyster planters of the York River trans- 
planted oysters from the same area to a river several miles from the 
York. The transplanting was done in March 1936, and the oysters 
