EFFECT OF CRUDE OIL POLLUTION ON OYSTERS 
153 
A number of reefs are said to be present in Bay Jacko, but the water was too 
shallow for the survey boat. 
TERREBONNE BAY 
This bay covers an area of about 100 square miles, exclusive of bayous, small 
lakes, and bays. Natural reefs are limited by soft bottom to bayous and the shores 
of islands in the bay. The section affected by mortality lies between Lake Barre 
and Terrebonne Bay. The heaviest losses in this region occurred in the vicinity of 
Lafont’s camp, as mentioned above. At the time of this survey, in February 1934, 
the better oysters were watery. Whether or not this is the usual condition during 
late winter could not be ascertained. 
This area is said to have produced large numbers of high quality oysters in the 
past. At present (1934) most of the oysters are used for steaming. 
At the 99 stations which were occupied on February 26-27 and March 5 and 8, 
salinities varied from 22 parts per thousand south of the Texas Co.’s wells, to over 32 
parts per thousand near the west end of Timbalier Island, and less than 30 at the east 
end of Wine Island. The opening between these islands is known locally as Cat 
Island Pass and is by far the largest pass in this region, being about 5.5 miles across. 
Isohalines show that the western side of the bay is slightly fresher than the east side, 
due apparently to drainage from Bayous Terrebonne and Little Caillou. 
Bottom temperatures on February 26-27 varied from 51° to 59° F. (10.6°-15°C.) ; 
on March 5 they averaged 64.5° F. (18.0° C.); on March 8 the average was 70° F. 
(21.1° C.). 
The depth varied from 4 to 10 feet. The lower part of the bay will average 
8 feet although there is a channel up to the Texas Co.’s wells through which 10 feet 
may be carried. The upper part of the bay is mostly 5 to 6 feet deep. 
TIMBALIER BAY 
This bay has an area of approximately 230 square miles, bisected by a string of 
islands lying in an east to west direction. Practically all of these islands have 
oyster beds around them. The bottom, except about Philobruis, is soft mud. 
The quality of the oysters varies greatly in the different sections of the bay. 
On the eastern side, including Devils Bay north through Jacks Camp Bay to Little 
Lake, excellent shell stock occurs, though on March 24, at the mouth of Bayou Grey 
and approximately 5 miles from the Leesville wells, the oysters had a pronounced 
oily taste. At Philobruis, 9 miles from the Leesville wells, oysters are of good quality 
for shell stock, no oily flavor could be detected, and no mortality was reported or 
observed. Practically the entire area between Philobruis and the eastern shore of 
the bay is covered with oyster reefs, all leased. Sponge, boring clam, and conchs 
are common. Most of the marketable oysters are between 2 and 3 years of age. 
The greatest mortality was reported in the vicinity of the islands Castete and 
Bull, about 14 miles from the Leesville wells, and 9 from the Barre wells. Dredgings 
made on March 13 consisted of about 90 percent shell. Numerous clean paired shells 
found at this station indicated that oysters continued to die. As a result of the 
mortality during the winter of 1932-33, no fresh plantings were made by the lease- 
holders in 1933. Local setting does not survive, so that seed must be brought from 
Lake Felicity or from the Louisiana marshes to the east of the Mississippi River. 
One hundred fifty-five stations were occupied during the 5 days of March 8, 
12, 13, 14, and 15. The salinity varied from 22 parts per thousand at Philobruis. 
