OYSTER BOTTOMS IN VICINITY OF APALACHICOLA, FLA. 63 
salt in solution. This mollusk thrives best in brackish water, having 
a mean between fresh (specific gravity 1.000) and open-sea water 
(specific gravity about 1.025). Either extreme, if continued, is 
decidedly injurious, if not fatal. Waters of rather high salinity are 
more favorable for drills or conchs, while mussels thrive in waters 
of low salt content. 
For the purpose of determining the general character of the waters, 
two separate but simultaneous series of observations of salinity and 
temperature were carefully made. From the Fish Hawk the work 
was performed by the quartermasters at 6 a. m., noon, and 6 p. m., 
daily throughout the survey. 
The vessel was first anchored off Cat Point, remaining there until - 
the latter part of February; then off Jetty Beacon for about one 
month; next, in southwestern part of Apalachicola Bay for about a 
week; and, finally, near the second anchorage until the completion 
of the survey. The biological party conducted the other series, 
which covered all parts of the region surveyed, including stations on 
the oyster bars and on unproductive grounds. 
The water bottle, or apparatus used for collecting the samples, is 
so constructed that it secures a uniform amount of water in every 
case from the layer a few inches above the bottom of the sound, 
regardless of the depth. This instrument is illustrated and described 
in ‘Volumetric studies of the food and feeding of oysters,’’ by H. F. 
Moore (Bulletin Bureau of Fisheries, vol. xxvii, p. 1297-1308). 
The following table furnishes a summary of the two series of 
observations. The boldface type shows the data and location of the 
Fish Hawk; the other type, that of the biological party. 
SALINITY AND TEMPERATURE OBSERVATIONS IN St. GEORGE SoUND, APALACHICOLA 
} Bay, AnD St. VINCENT SOUND. 
Water temperature. Specific gravity. 
Locality. Date. Me 
Maxi- | Mini- | Aver- Maxi- Mini- Aver- 
mum. | mum. | age. mum. mum. age. 
1915. °F. yi SF. 
Fish Hawk, off Cat Point. ..| Jan.12-15......... 59 48.2 53.2 1.0088 1.0026 | 1.0054 
Fish Hawk, off Cat Point...) Jan. 16-23......... 60.8 51.8 56.7 1.0093 1.0006 | 1.0058 
vari oe end of St. George |..... OE. ee eae 57.2 51.8 54.8 1.0190 1.0036 | 1.0113 
Sound, 
Fish Hawk, off Cat Point. ..| Jan. 24-31......... 59 53.6 58 1.0097 1.0041 | 1.0062 
ence of Porter and Plat- |..... 0. 55.4 51.8 54.4 1. 0088 1.0019 | 1.0056 
‘orm Bars. 
Fish Hawk, off Cat Point...) Feb. 1-5........... 60.8 53.6 59.4 1.0089 1.0014 | 1.0046 
E = gree Point and Bulk- |..... oli Ae ee 60.8 53.6 56.3 1. 0053 1. 0004 1. 0020 
nead Bars. . 
Fish Hawk, off Cat Point. ..| Feb. 6-10..........| 60.8 53.6 56.9 1.0032 1.0010 | 1.0019 
Vicinity of East Hole, Cabilecest ite =< 54.5 50 52.9 1. 0062 1.0001 | 1.0025 
Point, and Fast Bay. 
Fish Hawk, off Cat Point. . pon sity -aceel 60.8 54.5 56.9 1.0095 1.0025 | 1.0053 
Vicinity of Drum, Platform, eee cO oents ee Eee. 59. 9 53.6 57.7 1.0139 1.0022} 1.0070 
and Cat Point Bars. 
Fish Hawk, off Cat Point. ..} Feb. 18-22.........| 60.8 55.4 58 1.0220 1.0053 | 1.0158 
Vieinity of Pelican Bar, and |..... AGer eee ics « 58.1 57, 2 57.4 1.0218 1,0097 | 1.0172 
east part of Apalachicola 
Bay. 
