30 U. S. BUREAU OF FISHERIES 
Previous tagging had established the fact that the larger shrimp 
move south along the coast during winter, concentrating in the waters 
between St. Augustine and Cape Canaveral, Fla. Indications of a 
return northward movement had been obtained from length-frequency 
distributions and prior tagging. Conclusive evidence, however, of 
this return movement had not been secured. 
During 1938, 3,160 tagged shrimp were released from Cape Cana- 
veral to St. Augustine in January, February, and March, a period 
representing the height and decline of the Florida winter fishery. 
From releases at Cape Canaveral returns were secured as far north 
es Fripp Island, 8S. C., a distance of some 250 miles. It is therefore 
evident that a return movement does occur. Whether this return 
movement is made at random or represents the return of shrimp to 
the region where they originated has not yet been determined. 
Although the larger shrimp migrate to the southward during the 
winter, the small individuals remain in the local waters of Georgia. 
In January, February, and early March, 1,325 shrimp from this 
group were tagged and released in the area around Brunswick, Ga., in 
an effort to determine whether they also are migratory. The returns 
indicate that this class does not undertake any extensive movements. 
Additional tagging experiments in various areas along the entire 
coast would add materially to our knowledge of this group of so- 
called “local shrimp.” 
From April through August 3,200 tagged shrimp were released 
in the vicinity of Brunswick. The returns from these releases indi- 
cate that no extensive coastwise migrations were occurring at this 
season. 
Because of the extensive and continuous migrations and move- 
ments of the shrimp, growth determinations by length-frequency 
distributions cannot be relied upon to present a true picture of the 
rate of growth over any considerable period of time. Neither can 
study of growth of confined individuals represent the true growth 
rate, owning to the extreme difficulty or impossibility of duplicating 
the widely varied changes in habitat that the shrimp undergo as 
they increase in size. Tagging experiments, therefore, provide the 
best source of information on the growth of the shrimp in its nat- 
ural environment, as each shrimp is measured at release and upon 
recapture. Although many data have been accumulated, more tag- 
ging is required to arrive at an accurate approximation of the growth 
rate of shrimp during the different seasons of the year, and in dif- 
ferent. localities. 
The determination of fishing intensity has long been a difficult 
problem. Although the percentage of returns from tagging experi- 
ments gives some indication of fishing intensity, detailed and accurate 
catch statistics are also necessary. None of the States in the area 
covered by the shrimp fishery has gathered catch statistics Im a form 
suitable for analysis of the shrimp population density, a situation 
which is particularly deplorable in view of the magnitude of the 
fishery. Because of the lack of funds, personnel, and regulatory 
authority, it has been impossible for the shrimp staff to secure the 
necessary statistics. A serious effort was made during the year to 
secure voluntary cooperation of the fishermen in keeping daily catch 
records. Log books were provided to all boat captains willing to 
