The effect of salinity on utilization of shallow-water nursery habitats by aquatic fauna was assessed in San Antonio Bay, Texas. Overall, 272 samples were collected in a variety of marsh, vegetated, and non-vegetated habitats throughout the Bay system. Sampling began in fall 1986 and extended through fall 1989. Vegetated habitats, marsh, and submerged aquatic vegetation has significantly higher densities of fishes and decapod crustaceans than bare mud habitats.

Sampled marshes and ponds along two transects within the intermediate and brackish marsh zones of Breton Sound, Louisiana, from May 7-11, 2001. Sampling followed several planned releases of freshwater from the Caernarvon diversion structure during the winter of 2000 and spring of 2001 as part of a larger study to examine the ecological effect of pulsed freshwater releases on the ecosystem.

Terracing uses existing bottom sediments to form terraces or ridges at marsh elevation and the intertidal zone is planted with marsh vegetation. This study examined the habitat value of terracing at Sabine National Wildlife Refuge, Louisiana in the spring and fall of 1999 by quantifying and comparing nekton densities in a 9-yr old terrace field and nearby reference area using a 1 m2 drop sampler. Using density and biomass patterns and the percentage of marsh and pond area in the terrace field, we concluded that terrace fields support higher standing crops of most fishery species compared with shallow marsh ponds of similar size. Future restoration projects could include design changes to increase the proportion of marsh in a terrace field and enhance the habitat value of marsh terraces for fishery species.

Between May 5, 1993 and September 19, 1994, we collected quantitative 1-m2 area drop samples and measured a variety of habitat attributes using field surveys and aerial photography to characterize three existing marshes (Atkinson Island, Hog Island, and Cedar Point) in Galveston Bay. We also compared nekton densities among different types of intertidal and shallow subtidal habitats (pond, channel, cove, open bay, and four marsh types). The vegetated surface consistently contained more species and dominant species exhibited at least some degree of habitat selection. To maximize fishery habitat, we recommend placing greater emphasis on constructing low marsh edge habitat by creating large areas of Spartina alterniflora and Scirpus maritimus marsh interspersed with a dense network of shallow channels and interconnected ponds.

Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or destroy nonvegetated habitats in West Bay. Twenty-four 1.8-m diameter drop samples were taken in and around Halls Lake in West Galveston Bay during May, 1990 on daylight flood tides to provide information on the relative value of estuarine habitats for fishery species. Over 3,000 fish, shrimp, and crabs were collected from about 39 taxa. In conjunction with other published data on habitat value in Galveston Bay, our results indicate that for most crustacean, the Halls Lake marshes are more valuable than the other habitats examined. The relative value of the habitats for fishes was highly species-dependent. A survey of the West Bay shoreline indicated that valuable salt marsh habitats could be established on created barrier islands if direction of exposure and shoreline slope were controlled.

We sampled experimental research areas in the Barataria Basin of Louisiana during March and May, 1995, to examine the effects of structural marsh management on habitat use by small nekton (100 mm total length TL or carapace width CW). The research areas consisted of two control (unmanaged) marshes and two impounded (managed) marshes managed areas were surrounded by levees with water-control structures constructed by the U.S. Department of Interior, National Biological Survey. We conclude that the restricted water exchange in marshes under structural marsh management diminishes recruitment and standing stocks of species that must migrate from coastal spawning sites to marsh nurseries. Even when water-control structures were open, the densities of these transient species were low inside managed areas. In contrast to the negative effect of management on transient species, the resident fish and crustacean populations seemed to flourish in the managed areas when a drawdown was not in effect. Following two months of a drawdown, however, the populations of residents appeared similar inside and outside managed areas. Increases in submerged aquatic vegetation (SAV) within ponds occurred outside the managed areas during the study period, but not inside managed areas. Because many resident species were closely associated with the SAV, the effect of management on SAV may have been responsible for the distribution patterns of resident species.

Samples were collected from October 15, 1985 through June 12, 1987 in emergent marsh and non-vegetated habitats throughout the Lavaca Bay system to characterize usage of saline coastal and brackish deltaic habitats by estuarine aquatic species. Results suggest that short term lowering of salinity does not deter estuarine organisms from using deltaic marshes, but rather long term habitat changes may cause these responses

During July and October 1988, a total of 42 samples were collected in salt marsh habitats of the Caminada Bay system near Grand Isle, Louisiana to evaluate the use of the marsh surface by aquatic fauna on flood tide. Differences in animal densities between the marsh surface and nonvegetated marsh edge were compared and evaluated.