pulled 10 feet at seven selected locations in or near Airplane Lake. 

 A one-meter plankton net was fished for 15 minutes in the middle of 

 a major pass into Bay St. Honore. 



Laboratory techniques were developed to separate by genus and count 

 the specimens of animals that looked like shrimp. Post-larval brown 

 shrimp ( P. aztecus ) and white shrimp ( P. setiferus ) were removed 

 from the samples, identified, counted, and measured. 



The results indicated that 99 percent of the post-larvae migrate 

 on flood tides. Most of the larvae were caught at the surface day 

 or night, but more post-larvae were caught during the night than during 

 the day. During periods of a new or full moon, more post-larvae were 

 caught at all depths than during periods of first quarter or last 

 quarter moon. 



Most post-larvae were found to migrate toward Airplane Lake by the 

 most direct route using the main channel currents rather than following 

 the bay edges or crossing open bays without major currents. 



Some post-larvae dropped out of the main channel currents and used 

 the primary bays and bayous as nursery areas. The abundance of post- 

 larvae in Airplane Lake was found to be 0.135 post-larvae per square 

 meter. 



In deep channel water, more post-larvae were caught near the bottom 

 than at the surface on bright sunny days. 



Tables are provided showing the catch at each station over all trips. 

 (A. A.) 



Keywords: shrimp, behavior patterns, nursery areas, Louisiana 



IV-E-16 



Wallace, D.H. 1966. Oysters in the estuarine environment. Pages 68-73 



jjX American Fisheries Society, A symposium on estuarine fisheries. 



Washington, D.C. 



Production of oysters in many parts of the United States has been 

 reduced by environmental changes in the estuaries. Most of these 

 changes have been man-made and include such things as chemical and 

 biological contamination of the waters, physical destruction of the 

 bottom through dredging for fill material and channels, and alteration 

 of current and salinity patterns. Overfishing has decreased populations 

 in some estuaries, and diseases and predators have limited the ability 

 of oyster farmers to maintain a high level of production. 



186 



