PROGRESS IN BIOLOGICAL INQUIRIES, 1988 29 
a lay-up of 1 month for replacement. The boat was again placed in 
operation in July, but was laid up for engine repairs and for the 
duration of the dangerous hurricane season from August through 
October. Operations were resumed for a short period in November. 
The offshore area from Mobile, Ala., 60 miles north of Brownsville, 
Tex., was covered with the Pelican. In this region 402 trawl hauls 
were taken and 96 hydrographic stations were occupied. From each 
haul observations were made on the quantity, sex, length, and gonad 
development of the shrimp. At the hydrographic stations tempera- 
ture and salinity observations were secured for various depths, and 
core-tube and Petersen grab samples were obtained for study of the 
types of bottom and organisms present. ‘Trawling was done in 
depths up to 180 fathoms. It developed during the course of the 
work that a small 9-foot trawl, towed at full speed, was admirably 
suited for scouting. As much as 8 gallons of shrimp have been taken 
with this gear in a half-hour haul. 
That a winter concentration point for the larger common shrimp 
occurs off the Louisiana coast, in the region between Ship Shoal 
Buoy and Trinity Shoal Buoy, is quite evident from the data col- 
lected with the Pelican. As a result of the discovery of this area by 
the Bureau, boats operating from Morgan City, La., initiated a com- 
mercial fishery based on this offshore group of shrimp. A number 
of the Florida shrimp boats, which are better suited for offshore 
operations than the smaller and less seaworthy Louisiana craft, have 
migrated to Morgan City and Berwick, La., and have developed this 
fishery to one of considerable magnitude. 
No shrimp concentrations of any significant size were found be- 
tween the Alabama coast and the mouth of the Mississippi River. 
Off Texas during April the common shrimp appeared to be scattered 
about the 10-fathom contour, but with no evident heavy aggrega- 
tions. The less-abundant grooved shrimp was found in depths up 
to 70 fathoms but no commercial concentrations were encountered. 
Inasmuch as a considerable amount of offshore work remains to 
be done in the Gulf, it is planned to continue these operations during 
1939. The region between Mobile, Ala., and St. Marks, Fla., should 
be covered to determine the depth distribution of shrimp in this area 
and whether or not commercial concentrations occur. The Texas 
coast should be scouted as far south as the Mexican border during 
midwinter. The fishing grounds between Ship and Trinity Shoals 
should be covered at regular intervals during the spring, summer, 
and early fall to determine: (1) The extent and duration of the 
apparent onshore movement of the common shrimp during spring 
and early summer; (2) the fate of the adult spawning shrimp as the 
season progresses; (3) the magnitude of and the period covered by 
spawning; and (4) the time that the young shrimp begin to appear 
in this area after leaving the bays. 
TAGGING EXPERIMENTS 
For several years tagging experiments designed to provide informa- 
tion on migrations, growth rate, fishing intensity, and fate of the 
adult shrimp have been in progress throughout the South Atlantic 
shrimp fishing areas. Understanding of the fishery in this section 
depends largely upon the solution of these problems. 
162186—39——3 
