A COMPARISON OF WHITE SHRIMP PRODUCTION 



WITHIN ACTIVELY VERSUS PASSIVELY MANAGED 



SEMI-IMPOUNDED MARSH NURSERIES 



Ronald F. Paille, Fishery Biologist 



U.S. Fish and Wildlife Service 



825 Kaliste Saloon, Brandywine II 



Suite 102 



Lafayette, LA 70502 



Thomas J. Hess, Jr. 



Wetlands Consultant 



HPS Oil and Gas Properties 



Route 2, Box 35B 

 Grand Chenier, LA 70643 



Randal J. Moertle, Manager 

 Golden Ranch Farm 



P.O. Box 18 

 Gheens, LA 70355 



and 



Kenneth P. Guidry 



Land Management Consultant 



Route 6, 864 



Natchitoches, LA 71457 



ABSTRACT 



Published and unpublished data were used to compare white shrimp production within semi- 

 impoundments regulated by fixed-crest weirs and those regulated by variable-crest flap-gated water 

 control structures. White shrimp production in a semi-impounded marsh regulated by a variable- 

 crest flap-gated water control structure may have been substantially greater than white shrimp 

 production in a similar area regulated by a low-level, fixed-crest weir. Operation of a variable- 

 crest flap-gated water control structure allowed relatively severe reduction to be effected in the 

 volume of water exchange without a proportional reduction in white shrimp production. However, 

 the timing of flap-gate operation was an important variable in this relationship. 



INTRODUCTION 



Marsh management practices of the mid-1960's consisted primarily of passive estuarine 

 management (Wicker et al. 1983) accomplished through the placement of fixed-crest weirs in 

 natural drainages. These drainages often served as the principal avenue of water exchange for 

 areas that were hydrologically isolated by natural levees/spoil banks, and road embankments. This 

 form of management is passive because the structures are fixed and involve no active operation. 

 In this paper, a marsh is considered to be semi-impounded when spoil banks, natural levees, or 

 embankments limit water exchange to one or more fixed openings or water control structures. 



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