Tulian. — Louisiana Shrimp Industry. 113 



number of the small and young fish alive. In the first place, 

 the secretion produced by the shrimp is continually carried 

 away by the current of water passing through the trawl, and 

 its eft^cts must be certainly minimized. Next, the smaller 

 number and aggregation of fish, especially the absence of 

 such abundant species as menhaden, and washing away 

 of what mucous there is prevents the accumulation on the 

 gills »s in the case of seines. The smaller bulk of the catch 

 and the shorter time required to unload and separate the 

 catch are also factors to be considered. While the catch is 

 being scooped out, the trawl is generally dragging through 

 clear clean water at the surface, instead of the muddy water 

 near the shore. Another thing must not be lost sight of. 

 Typical bottom species, being associated with mud, natural 

 pollution, and less oxygen, are fortified by nature to resist 

 these conditions, and therefore those food species caught in 

 the trawls are generally the very ones which survive above 

 all others. Those returned to the open water, especially 

 during the colder months, stand a much greater chance of 

 survival than the less hardy shore or surface feeders or for 

 that matter than the same species liberated from the seines 

 in shallow muddy water. 



Another factor in favor of the trawl is that most large 

 fish seem to escape, no doubt due to their own alertness and 

 rapid swimming. The rate of motion of the trawl is rela- 

 tively slow and the disturbance is sufliicient to permit their 

 escape. The shrimp seine on the other hand catches large 

 and small fish of all kinds because of the large area sur- 

 rounded. The escape of the large fish from the trawl partly 

 compensates for the young of any species destroyed. 



Since my last paper before this Society, there has been 

 done much research work pertaining to the life history of 

 the premiere shrimp found in our waters, and Mr. Percy 

 Viosca, Jr. M. S. Biologist of the Fisheries Division of the 

 Department of Conservation of Louisiana, has gotten to- 

 gether a great deal of information on this subject. His 

 previous work has been amplified and as a consequence, 

 the Department possesses more intimate knowledge of the 

 life history and habits of the shrimp, Penaceus setiferus, 

 than any other denizen of our v/aters. Many of the remarks 

 made in this paper are based on his field observations. 



I will conclude this paper by incorporating bodily, a 

 report made by Mr. Viosca to this Department, which 

 summarizes our present day knowledge of the life history 

 and habits of Penaeus setiferus. 



"The following is a summary of the results of studies of 

 Penaeus setiferus, which have been taken up since July 



