Tulian. — Shrimp Production in Louisiana 119 



The southern prawn, Penceus setiferus, is usually known in 

 Louisiana as the "lake shrimp." This name was derived from 

 the fact that at certain seasons of the year they are abundant 

 in all of our brackish waters, bays and lakes. The name, however, 

 is a little misleading and we find that it can not truly be applied 

 to the adults of the species, which on the Louisiana coast are 

 confined solely to the waters of the Gulf. All specimens found in 

 land-locked bays and lakes are now known to be immature speci- 

 mens. Considering shrimp of commercial size, irrespective of 

 sexual maturity, we might say that their habitat consists of all the 

 salt and brackish water lakes, bays and bayous of our state, 

 extending at times into some of our fresh water lakes where 

 biological conditions are suited to their growth. Indications are 

 that they may even be abundant far out from shore in unexplored 

 regions of the Gulf. 



The shrimp under consideration are the chief and most efficient 

 scavengers of the open areas of our lake and sea bottoms, and 

 in their search for food they are constantly moving about from 

 place to place picking up all available particles of plant and animal 

 matter. In the sea their food consists of the debris and remains 

 of practically all forms of marine life, the higher as well as the 

 lower forms, such as hydroids, bryozoa, worms, crustaceans 

 and sea- weeds, etc. In the bays and lakes, surrounded by our 

 salt marsh country, their food is composed largely of small pieces 

 of the roots, stems, and leaves of the salt marsh grasses, which are 

 constantly washed into these bodies of water by the waves and 

 receding tides. As long as our salt marshes exist, there is little 

 danger of their food supply running short, and in this respect 

 our salt marshes are a valuable asset to the state. 



Penceus setiferus is a migratory species, but its movements are 

 often difficult to follow, being very erratic. Observations tend 

 to show that they usually travel slowly along the bottom, feeding 

 meanwhile as they crawl along by means of their walking legs 

 and swimmerets. In places where their food is abundant, shrimp 

 accumulate in large schools, muddying the water as they feed. 

 Aside from attraction by food, another cause of their migrations 

 appears to be the currents, which are caused by a complicated 

 set of factors; the normal bayou or river current, the tides, and 

 the winds, which latter is often the most important. Sometimes 



