PROGRESS IN BIOLOGICAL INQUIRIES, 1939 69 
pose the Bureau took possession of the abandoned Pensacola Quar- 
antine Station and adapted it to the needs of the shellfish inves- 
tigations, with the aid of W. P. A. funds. Construction work at the 
station is expected to completed during 1940. 
In carrying out scientific investigations, Dr. A. E. Hopkins, direc- 
tor of the station, has cooperated extensively with oystermen and 
with conservation departments of the Gulf Coast States in formu- 
lating programs for the development and maintenance of natural 
oyster grounds, and the creation of new grounds, by planting seed 
and shells. In Florida, especially, much progress has been made in 
projects of this kind with the assistance of the W. P. A. During the 
year, surveys were made of the oyster grounds of Mobile Bay, ‘Ala., 
und connected waters, and cooperation. was given to the Alabama 
Department of Conservation in promulgating regulations designed to 
restore the grounds to their former productivity. 
An experimental study was planned to obtain exact data on the 
effect of variations in salinity on oysters. However, the work has 
been deferred pending completion of large outdoor concrete tanks 
where the experiments can be carried on under controlled conditions. 
Observations were made during the summer in East Pensacola Bay, 
where there was a large mortality during a period of low salinity. 
Counts of live oysters “and the intact shells of those that had died 
recently showed a mortality of 90.3 percent. The mortality was diffi- 
cult to understand, since the freshet condition lasted only about 3 
weeks, and since the oyster grounds are so located that they are sup- 
pled with salt water from “the Gulf at high tide. A study of the 
data available indicates that the mortality was the result of a com- 
bination of factors, one of which was low salinity. The oysters had 
been heavily infested with a sporozoan parasite, Nematopsi iS OS- 
trearum, which appeared to render the oysters less resistant to han- 
dling or transplanting. Also, the period of low salinity occurred in 
August, immediately after the oysters had completely spawned out 
and their resistance was greatly lowered. It is probable that low 
salinity decreases the feeding activities of Ostrea virginica. Dr. Hop- 
kins found the same relationship between reduced feeding activity and 
low salinity in Ostrea gigas. The problem of the effect of salinity 
on oysters will be thoroughly studied as soon as possible. 
RESPIRATION OF THE OYSTER 
During past years considerable information has been accumulated 
by the Bureau's inv estigators regarding the nutritive value of oysters 
from different sections ‘of the coast, and regarding the seasonal fluc- 
tuations in the mineral, water, and elycogen content of oysters in 
Long Island Sound. There is no doubt that the good qualities of 
marketable oysters are determined by a high percentage of solids, 
high glycogen content, and the presence of sufficient amounts of 
metals such as calcium, iron, copper, and iodine—important in a 
well-balanced human diet. The importance of producing oysters of 
highest nutritive value is now being recognized by the majority of the 
leading oyster growers. The difficulty lies, however, in the fact that 
present observational data provide no clue to the methods or pro- 
cedures by which oysters of desired qualities could be produced. 
Practical solution of this problem rests on fundamental knowledge of 
