Figure 4. Detailed diagram of the trap system for the paired ponds shown in Figure 3. 



Several of our studies have indicated that the habitat in semi-impounded areas is suitable for a 

 number of estuarine-dependent fisheries species, even though their production there may be 

 considerably reduced. We believe the reduced production is primarily due to too few of the young 

 being able to get into the semi-impounded area. Using our same paired pond study site just 

 described, Bradshaw (1985) found such to be the case for brown shrimp. 



In another study at the same site, funded by the U.S. Army Corps of Engineers, the Louisiana 

 Department of Natural Resources, and the Louisiana State University Coastal Fisheries Institute, 

 we tested a modification of the standard fixed-crest weir that allowed increased access by 

 immigrating brown shrimp to see if greater production would occur. A standard fixed-crest weir, 

 with the crest then set 15 cm below average marsh ground level, was placed in the chute to one 

 pond. The weir placed in the other chute was identical except for a 10-cm-wide slot from top to 

 bottom. This was done in December 1985 prior to the onset of immigration of the 1986 crop of 

 young brown shrimp. 



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