24 
BULLETIN OF THE BUREAU OF FISHERIES 
Of the six species of shrimp caught in the South the common shrimp ( Penaeus 
setiferus ) is the most valuable. This species comprises about 95 percent of the catch 
in the South Atlantic and Gulf States, or about 90 percent of the entire amount of 
shrimp taken in the United States. 
P. setiferus spawns from March or April to August or September apparently in the 
outside waters. 
The post-larval young, measuring from 7 or 8 mm up, are first encountered in 
bays, bayous, and “lakes”, sometimes far inland, but not on ocean or Gulf beaches. 
Their habitat is warm, shallow, brackish waters with muddy bottoms. 
The young grow rapidly, and as they grow they seek deeper waters of greater 
salinity. During July, at an average size of about 90 mm, they enter the commercial 
catch, first on the inside, later outside. They continue in the fishery until the fol- 
lowing spring and summer, when they spawn and disappear at the age of 1 year. 
During this time they grow to a length of about 120 mm; remain at this size through 
the winter, resume growth in the spring; and, after a rapid differentiation of the size 
of the sexes, spawn at length about 130 to 170 mm for the males and 135 to 190 mm for 
the females. Their fate is unknown, but that they disappear from the commercial 
catch following spawning is undoubted. 
During the breeding season in the inside waters of Georgia there is a much greater 
proportion of females than males, while in the outside waters there is a greater propor- 
tion of males. 
In Georgia at the beginning of the breeding season there is evident a differential 
behavior of the males and females ; a differential growth rate between the sexes, with 
the females outstripping the males; and a change in the length frequency groupings 
from a wide to a very narrow range. 
The common shrimp is most abundant in the coastal waters near river mouths or 
delta regions. It is omnivorous in its feeding habits. At present the shrimp fishery 
does not appear to show serious depletion, consequently increased stringency of exist- 
ing laws is not imperative. 
In the life history of the shrimp there are two factors favoring depletion — the 
short life span and exposure to fishing at all times. On the other hand, there are two 
factors opposing depletion- — the extended breeding season and the large number of 
eggs produced. The most recent and at present one of the most decisive factors of the 
environment is the fishing of man. To date the favoring factors have maintained a 
vast shrimp population. With a more and more intensive fishery, the unfavorable 
factors must at some time become the more powerful. Because of the short life of the 
common shrimp, depletion, when it appears, will probably run a disastrously rapid 
course; consequently vigilance in safeguarding the industry is necessary. Against 
this time, methods of protection must be carefully planned. 
There are four types of regulation applicable to the shrimp fishery; namely, 
closed seasons, closed areas, size limits, and restriction of gear. The fishery records 
of the various States are entirely inadequate to permit an analysis of abundance. For 
the safety of the shrimp industries it is imperative that this lack of catch records should 
speedily be remedied. It is recommended that all States collect on a standard form 
uniform records of the daily catch of each fisherman; certain of the States are now 
working on this problem. It is only by such records that any accurate indication of 
threatened depletion may be detected. 
