6 
BULLETIN OF THE BUREAU OF FISHERIES 
A fishery of this magnitude, the most important in the South, giving employ- 
ment to thousands of fishermen and factory operatives, deserves careful attention if 
it is to be maintained in this valuable state. The rapid expansion of the fishery 
during the past 40 years, throughout which time it has doubled in volume every 8 
or 9 years, has suggested caution, and recently the men in the industry have taken 
the initiative in asking for investigation, fearing, apparently, that some of the 
fluctuations in the catch were the forerunners of serious depletion. The prime 
requisites for successful handling of the problems of the shrimp, as of other fishery 
resources not adapted to cultivation, are information as to the abundance and 
knowledge of the life history. The first is needed to tell when protection is required 
and the second to guide such protection into intelligent and effective channels. 
Unfortunately data for even the roughest analysis of abundance is lacking. 
State and Federal data give only the total catch and except for the last year or so no 
indication of the effort that produced the catch. Some private records alone serve 
to show the boat catches by which the effort could be analyzed, but these records are 
too scattered and cover too short a time to solve the problem. The outlook in this 
direction is, however, now more hopeful, for in Louisiana, a law, originally drafted 
with the assistance of members of our staff, in the future will give figures from which 
depletion may be detected as it appears. In consequence of these conditions we are 
unable to present in this report any data on the important question of abundance. 
On the other hand, we must have an adequate knowledge of the life history and 
habits of the shrimp in order that, should depletion become apparent, intelligent pro- 
tective measures may be applied at once. The only purpose of this preliminary 
report is to make available what information has been obtained against the time when 
it may be necessary to frame protective measures. Data on many points are far from 
conclusive but still may be useful for legislative action ; the paper must be considered 
solely as such a progress report in spite of the fact that the data at hand establish a 
more complete life history than has hitherto been available for any shrimp of economic 
importance. 
PREVIOUS WORK ON LIFE HISTORY 
At the time the present investigation was started the information available con- 
cerning the American penaeids, and especially Penaeus setiferus, other than that in 
purely systematic papers was very meager. Fritz Muller in 1863 had reported from 
Brazil the occurrence of a nauplius larva presumably belonging to the genus Penaeus. 
In 1883 Brooks obtained penaeid larvae at Beaufort, N.C., and was able to trace the 
main stages of the larval history. He assumed them to be the young of Penaeus 
brasiliensis, but neither he nor Muller established the specific characters for the larvae. 
This work was solely morphological, interest being centered in the occurrence of the 
primitive nauplius larvae previously found only in lower Crustacea. 
In this connection it may be well to point out a peculiarity of the Penaeidae which 
has made study of the life history difficult. Unlike the majority of the higher Crus- 
tacea, the female penaeid does not carry the developing eggs attached to the abdomi- 
nal legs. In consequence, although eggs of the other shrimp and crabs, as for example 
Crago vulgaris of the North Sea, may readily be obtained for study, no one has ever 
reported a fertilized egg of Penaeus. The mature ovarian egg is very small, measur- 
ing from one fourth to one third of a millimeter in diameter, and the unique larval 
history of Penaeus is related to this fact. The minute larvae hatching as nauplii pass 
through 6 or 8 distinct stages, in contrast to the condensed development of most deca- 
