LIFE HISTORY OF THE COMMON SHRIMP 
21 
Kishinouye (1900a) believes that certain species of Penaeus die after spawning 
while others live through a second year. He does not indicate the basis of this belief. 
Without evidence, it is idle to speculate whether the process of spawning is 
fatal to the shrimp — whether, like the salmon, they are weakened and soon succumb 
to enemies and disease or whether they retire to some new and as yet undiscovered 
habitat. All we know is that they play no further part in the fishery. The shrimp 
is therefore an “annual”, being spawned in the spring or summer, spawning at the 
same season of the following year, and then passing out of the fishery. Since it is 
probable that those spawned early furnish the early spawners of the next year, the 
life span is very close to 1 year. This is the condition in Georgia. Whether or not 
in Louisiana and Texas the life span will prove to be the same is not yet settled, but 
the data so far available give no evidence of an essentially different life history. 
It should again be emphasized that the above account refers only to P. setiferus. 
How many of these findings may apply to P. brasiliensis, Xiphopenaeus kroyeri, and 
Trachy penaeus constrictus remains to be determined. A consideration of these forms 
has been deferred because of their lesser importance and because data on these less 
common species has accumulated far more slowly. 
HABITS 
Observation of the shrimp under natural conditions is so difficult that only the 
most obvious habits can be thus determined. Systematic observations in aquaria 
have not yet been carried out. In spite of the paucity of direct observation it may 
be well to assemble what general knowledge is available. As already stated, Penaeus 
setiferus, like other penaeids, is a shrimp of subtropical littoral waters. The range 
of temperature under which we have taken it is 9° to 31° C. (48° to 88° F.). In the 
colder waters of the North Sea in Europe or of Alaska no penaeids are taken, the 
fishery depending rather on pandalids or cragonids. As with the Indian species 
observed by Alcock, P. setiferus appears to favor the deltas of large rivers like the 
Mississippi, although it is not confined to such localities. For example, shrimp are 
taken in large numbers off Cape Canaveral, Fla., in a region where there are no 
large streams. Perhaps the relation to rivers rests on the fact that, as we have seen, 
the young for part of their development frequent brackish or almost fresh water. 
It appears to be more common on muddy than on sandy bottoms, but it must 
be remembered that mud is more common than sand in the neighborhood of large 
deltas. 
Like other shrimp, Penaeus setiferus swims in two ways. Usually it swims for- 
ward by means of the pleopods or abdominal legs. When moving rapidly it swims 
or rather leaps backward by flexing the powerful muscular abdomen and sweeping 
the large tail fin under the body. In this way it may leap out of the water like a 
fish or out of an uncovered aquarium. 
Although the shrimp spend most of their time on the bottom, there are a few 
well-authenticated cases where a school has been seen swimming near the surface. 
At times they bury themselves in the mud. 
No systematic examination of the stomach contents has been carried out, but a 
few observations indicate that it is a voracious and well-nigh omnivorous feeder. This 
is supported by the observation of Viosca (Tulian 1920), and of Alcock (1906) and 
Kishinouye (1900a) on other species. Worms, Crustacea (not excluding shrimp of the 
