PROGRESS IN BIOLOGICAL INQUIRIES, 1936 43 
OBSERVATIONS ON OYSTER BARS IN APALACHICOLA BAY, FLA. 
During the year hydrographic surveys were made by R. O. Smith 
from January 16 to September 3, covering 45 stations in St. Vincent 
Sound, Apalachicola Bay, and St. Geor ge ; Sound. Nineteen of these 
stations are located on oyster bars. The surveys were undertaken 
with the view of obtaining a better understanding of the correlations 
between fluctuations in temperature, salinity, and turbidity of the 
water and the productivity of the oyster bars. 
It has been found that most abundant setting occurs in the zone 
where large fluctuations in salinity occur, but that market oysters of 
the best quality are taken from areas of relatively high salinity. The 
northern ends of St. Vincent, Cat Point, Peanut Patch, and Bulkhead 
Bars, where salinity variations are @ oreatest, are the most heavily pop- 
ulated but seldom produce oysters of large size, good shape, or desir- 
able fatness of meats. On the other hand, Porters Bar in St. George 
Sound and bars in the western end of St. Vincent Sound are regularly 
fished out as they produce the best quality meats in this region. 
In summarizing the condition of the bars in 1935 it was stated that 
unless additional areas can be brought into production, the present 
rate of fishing on producing bars will result in a steady decline in 
size and quality of the shell stock. This prediction has been realized 
during the present season, when the oysters were small (400 to 700 per 
gallon), and of poor quality. Planting of oysters and cultch is still 
urgently needed and adequate supplies of seed are available from 
Platform Bar. 
OYSTER INVESTIGATIONS ON THE PACIFIC COAST 
After 5 years of intensive investigation of the history of the native 
oyster of the Pacific coast at Olympia, Wash., by Dr. A. E. Hopkins, 
a report summarizing the significant results was prepared for pub- 
lication and the work discontinued. The results of this work have 
already proven of definite value to the oyster growers and it is ex- 
pected that they will be increasingly useful in the future. In the 
southern portion of Puget Sound where the average range of tide is 
14 feet and the maximum range 20 feet, the grounds on which Olympia 
oysters are cultivated are located generally between the minus 2 foot 
and the plus 4 foot tide levels and are all exposed at extreme low tide. 
Most grounds are leveled and surrounded by dikes which retain a 
few inches of water over the oysters at low tide. 
Market-sized Olympia oysters, which are hermaphroditic and vivi- 
parous, bear broods of 250,000 to 300,000 larvae. In general, the 
larger the oyster, the larger the number of larvae produced. Usually 
an oyster produces one brood each season, though in some years as 
many as 50 percent may bear second broods also. On the other hand, 
during some seasons only about 75 percent of adults bear broods. 
Spawning of functional females begins in the spring when the 
minimum water temperature at high ‘tide reaches 12.5° to 13° C. 
(critical temperature), and most br oods are produced during a period 
of about 6 weeks at the beginning of the spawning season, although 
an occasional gravid individual may be found as late as October. 
An average period of 10 days is required for the larvae to develop 
within the maternal brood chamber from eggs of 100u to 105p in 
