20 
BULLETIN OF THE BUREAU OF FISHERIES 
this peak the abundance declines and reaches a low point in late winter and early 
spring, coinciding with the low point of the catch which falls in February, March, or 
April. 
The numbers obtained by experimental trawling then again increase, reaching a 
second peak in April or Maj 7 at the time of the spring catch of large, mature shrimp 
so prized by the canners. The crest is more prominent and earlier than the spring 
catch would suggest. 
From this peak of abundance there is a rapid and steady decline. In the first 
half of July, when the young of the year make their first appearance in the commer- 
cial catch, the two groups are approximately equal in abundance. By the latter 
part of the month the abundance of the group of larger shrimp has already fallen 
>- 
■< 
2 
Ol. 
uJ 
tO 
Figure 11— Average monthly shrimp catch in Georgia from 1926 to 1931, inclusive. The average monthly polygons for Louisiana 
and Texas follow the Georgia polygon very closely. 
below that of the growing young. The group of large shrimp can be more or less 
clearly recognized in August by their greater length, but the rapid growth of the 
young (see fig. 10) soon brings about an overlap, so that size alone will not suffice to 
identify them. The group of large shrimp are at this time sexually mature, and by 
this criterion a few may be found in September, but the number is very small — two 
or three out of hundreds. A careful study of the size frequency curves and those of 
sexual maturity fail to disclose further trace of them, and we are forced to conclude 
that they disappear from the fishery in Georgia. We have also been unable to find 
spent individuals such as should be present after the spawning season if the adults 
remained within the range of the fishery. Among the thousands of immature shrimp 
no undoubtedly spent female has been found, although some males examined may 
possibly belong to this category; the number of these, however, is small. 
