a8 . U.S. BUREAU OF FISHERIES 
Commissioner Rankin, of the Louisiana Department of Conservation, 
kindly arranged to supply more spacious quarters for the staff and 
collections at 336 Chartres St., New Orleans, La. The city of Gulf- 
port, Miss., has continued to furnish dockage space for the Pelican 
and a storage room for equipment. Arrangements have been made 
with Dr. A. E. Parr, of Yale University, for analyses of the water 
samples, and with Dr. Dana Russell, of Louisiana State University, 
for analyses of the bottom core and mud samples taken during the 
cruises of the Pelican. 
In the course of the shrimp investigations, which have been under 
way since 1931, it has been found that the common shrimp spawns 
during the spring and summer in the open waters of the Atlantic 
Ocean and the Gulf of Mexico. The eggs are not carried by the 
female but are extruded directly into the water. The young enter 
the inland waters at an early stage in their development. The exten- 
sive inland water areas of the South are the nursery grounds of the 
shrimp, where the young feed and grow. Those young not success- 
ful in reaching the nursery grounds perish. As the immature 
shrimp Increase in size they gradually leave the nursery grounds and 
return to the ocean. The growth rate of the shrimp is quite rapid, 
and by mid-June or July, depending upon the locality, the young 
are of sufficient size to appear in the commercial fishery. By Sep- 
tember, practically the entire catch is composed of these immature 
shrimp, for the adults disappear from the fishery as spawning 
progresses. Sexual maturity is attained in 1 year. The movements 
and behavior of the shrimp are affected by temperature, salinity, and 
tides. 
Tagging experiments have demonstrated that shrimp are migra- 
tory. During the fall and winter the larger shrimp move south 
along the Atlantic coast from North Carolina, South Carolina, and 
Georgia into the waters off the coast of central Florida. In several 
instances tagged individuals have been picked up more than 300 miles 
from the place of release. The smaller shrimp, however, tend to 
remain in Jocal waters and are not subject to such extensive move- 
ments. 
In the Gulf of Mexico it was suspected that the larger shrimp, 
from the Louisiana coast at least, move off into deeper waters during 
the winter. With a suitable vessel and the proper equipment it was 
considered highly probable that a new winter fishery could be de- 
veloped off the Louisiana coast. The Pelican was transferred to the 
Shrimp Investigations in 1937 for this purpose, but, owing to lack 
of funds, operation of the boat was deferred until January 1938. 
The major program of work undertaken during the year falls into 
three general categories, namely: Offshore scouting operations with 
the Pelican in the Gulf of Mexico, tagging experiments along the 
Atlantic coast and the Louisiana coast, and ecological studies in 
Texas. 
OFFSHORE OPERATIONS 
Among the results of the 1938 investigations, the event of out- 
standing importance to the commercial fishery was the discovery of 
a winter concentration area for large shrimp off the central Louisiana 
coast. The Pelican began operations in January and operated con- 
tinuously until June, when the less of the trawling cable necessitated 
a 
