macro-fauna other than shrimp. The impact of these changes on the total 

 marsh ecosystem is not known but should be considered and studied 

 in detail before ponds are constructed. Conceivably, marsh areas 

 could be managed so as to insure a reasonable amount of habitat for 

 the stable macro-fauna while allowing ample lands for shrimp culture. 

 This could best be accomplished by restricting shrimp culture practices 

 to open water areas, thus avoiding the removal of flooded grasslands. 

 In addition, the pond flumes could be opened to the surrounding marsh 

 during the winter months when temperatures are too low for shrimp 

 culture, allowing the impounded areas to return to a more or less 

 natural state. (A.A.) 



Keywords: coastal marsh, macro-fauna, shrimp, Texas, Galveston Bay 



IV-D-5 



Conner, J.V., and F.M. Truesdale. 1973. Ecological implications of a 

 freshwater impoundment in a low-salinity marsh. Pages 259-276 jn_ 

 R.H. Chabreck, ed.. Proceedings of the coastal marsh and estuary 

 management symposium. Louisiana State University, Baton Rouge. 



A three-year study of a low-salinity marsh area in the Galveston 

 Bay System of Texas revealed that certain of the marsh waters were 

 prime habitat for the post-larvae and/or juveniles of several marine 

 crustaceans and fishes, including commercial shrimps, Gulf menhaden, 

 Atlantic croakers, sand seatrout, and southern flounder. Results of 

 this and other investigations indicated that shallow, turbid, soft-bottomed 

 lakes and blind bayous in the interior of marsh areas are the "target" 

 habitats of many migrating young marine animals. Comparative catches 

 per effort using the same gear in various portions of the Galveston 

 estuary show, in general, that peripheral marsh waters can be much 

 more productive per unit area than the more expansive open waters of 

 the bays. There are further indications that brackish marshes asso- 

 ciated with the upper estuary are more productive for some species 

 than higher-salinity marshes of the lower bays. Therefore, a 7,200-acre 

 section to be impounded in the Trinity River Delta, Chambers County, 

 Texas, cannot be regarded as roughly equivalent in importance as 

 "nursery habitat" as any other 7,200-acre area in the Galveston Bay 

 System. The inability to make reliable estimates of the absolute 

 value of a given estuarine habitat has been invoked as ground for 

 disregarding possible losses to the commercial fisheries. If special 

 habitat types within an estuary are to be protected from destruction, 

 biologists must devise methods for estimating the absolute values of 

 such habitats in terms of their ultimate contribution to fisheries 

 harvests. (A.A.) 



Keywords: low-salinity marsh, marine animals, productivity, Texas 



164 



