Tulian. — Shrimp Production in Louisiana 121 



in which conditions are suited to their growth. By watching the 

 growth of the maximum-size specimens, of this so-called summer 

 crop, we have gained some idea of the rate of growth, or at least 

 know something of its order of magnitude. This seems to average 

 somewhere between one half and one inch per month and as the 

 smallest adult shrimp are six inches in length, it would take some- 

 where between six and twelve months for a shrimp to grow to 

 maturity; (the latest observations point to the former period). 

 The young shrimp found in the shallow waters near the sea coast 

 in the early summer, spread in all directions and by the end of Sep- 

 tember specimens are found far inland, even in fresh water lakes. 

 All this time they have been growing and, as they do so, they seek 

 the deeper waters, being replaced gradually in the shallow places 

 by successive crops of younger specimens. At this time, that is, 

 during the fall, the migration of the largest specimens back towards 

 the sea begins to take place, while other small shrimp are con- 

 tinuing to make their way inland. 



We must at all times keep one thing in mind, however, that 

 shrimp are greatly affected by weather conditions and changing 

 currents and this general migration is often obscured by many 

 complications. In the winter months especially, conditions are 

 much changed and the growing shrimp cannot advance as far 

 inland, perhaps partly, because of the cold and partly because of 

 the currents caused by the winter rains, there is a change in the 

 physical and biological conditions of the inside waters, 



Although (owing to the influenza epidemic) our observations 

 during the winter months are rather incomplete, nevertheless 

 there appears to be a period during the coldest part of the year 

 when either no eggs are laid or; at any rate, we are sure that no 

 young make their appearance in our inside waters, as by the end 

 of February it is rare that we find any shrimp anywhere under two 

 and a half inches. By watching the growth during the spring 

 months, of these minimum-sized specimens, we can arrive at an 

 estimate of the approximate rate of growth. This corresponds 

 closely to the figure obtained for the summer growth. By the 

 middle of May the smallest shrimp had already grown to five 

 inches and the new crop had made its first appearance, the largest 

 specimens of which were already two inches. It is a significant 

 fact that, in spite of the immense amount of material examined 



