farthest from the bay the numbers of species decline. Twenty-nine 



species were caught on the bay, seventeen on the salt flats, eight in 



freshwater ponds having had previous connections with the bay, and 

 four in an isolated freshwater pond. (H.D.) 



Keywords: fishes, life history, killifishes, salinity, Texas coast 



IV-D-4 



Parker, J.C, H.W. Holcomb, W.G. Klussman, and J.C. McNeill. 1971. Distribution 



of aquatic macro-fauna in a marsh on West Galveston Bay, Texas, and possible 



effects thereon resulting from impoundments for shrimp culture. Texas 



A & M University, Sea Grant Publication No. TAMU-SG-71-208. 38 pp. 



A survey was conducted to identify the macro-fauna of a marsh adjacent 

 to West Galveston Bay. The factors affecting their distribution were 

 studied to help evaluate changes that might result in the event that 

 large areas of the marsh were impounded for shrimp culture. 



As a result of frequent tidal floods, saline conditions generally 

 prevailed within the marsh. Freshwater floods resulting from local 

 rainfall were common, but salt leached from the bottom sediments, 

 coupled with subsequent tidal floods, readily re-established saline 

 conditions. 



The fauna consisted of a variety of marine and estuarine species. 

 Those species that were abundant throughout the year and constituted 

 the stable macro-fauna were Cyprinodon varieqatus , Fundulus grandis , 

 Poecilia lati pinna , Mugil cephalus , Menidia beryl lina , Palaemonetes 

 sp., and Callinectes sapidus . These are among the hardiest of coastal 

 aquatic animals and exhibited broad temperature and salinity tolerances. 



Marine-dependent species were able to enter the marsh during tidal 

 floods and many were trapped when waters receded. Post-larvae of some 

 of these species were able to invade the marsh at normal tide level 

 through narrow, vegetation-clogged ditches leading inland from the 

 bay. Conditions were seldom favorable, however, for the return of 

 marine species to the bay. They usually died as a result of low 

 temperatures during the winter or drought conditions during the summer. 

 These species generally disappeared from the marsh following freshwater 

 floods and it was assumed that they were either forced out into the 

 bay or died as a result of the rapid salinity decline which typically 

 occurred. 



Construction of large-scale impoundments for shrimp culture, at the 

 expense of removing flooded grasslands, would alter the physical 

 features of the marsh and reduce habitat suitable for year-round 

 survival of the stable macro-fauna. In addition, competitor and 

 predator control in these ponds would require the removal of all aquatic 



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