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.

The Calcasieu Ship Channel provides an avenue for the rapid movement of high-salinity water into the East Mud Lake project area of southern Louisiana resulting in plant death and marsh loss. Following construction of water control structures at East Mud Lake designed to stabilize salinity and water levels and ensure movement of commercial species into and out of the project area, densities of nekton and the extent of vegetative cover were assessed and compared for project and reference sites to estimate the impact of construction on wetland habitats.

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.

Marsh terracing is used to restore coastal wetlands by converting shallow nonvegetated bottom to intertidal marsh. Terraces are constructed from excavated bottom sediments, and are commonly arranged in a checkerboard pattern of square cells with open corners to form terrace fields. The project was located in shallow estuarine waters, and used bottom sediments or upland soils to construct intertidal areas planted with smooth cordgrass, Spartina alterniflora. We used a quantitative sampling device to compare nekton densities and biomass in habitat types of marsh terraces of three cell sizes at Pierce Marsh in Galveston Bay to a nearby reference marsh. Within terrace cells, density, biomass, and species richness were generally higher in marsh vegetation than over nonvegetated bottom. We also used Geographic Information System (GIS) and high-resolution aerial photography to classify areas into land (marsh vegetation) and water and applied fishery density models to assess fishery support. These models describe finescale distribution patterns for brown shrimp Farfantepenaeus aztecus, white shrimp Litopenaeus setiferus, and blue crab Callinectes sapidus across shallow estuarine habitat types (emergent marsh and shallow open water) of Galveston Bay. We show that populations of most fishery species increase as cell size decreases. However, as cell size decreases, the cost of terrace construction increases much faster than population size. Therefore, terrace fields constructed of medium or large cells would be more cost effective in providing fishery habitat than would terraces composed of small cells. Based on our modeling results, restored sites supported relatively high populations of fishery species compared to pre-restoration conditions. However, restoration sites did not support populations’ equivalent to a reference marsh system. Restoration projects should maximize the area of marsh vegetation and create a high degree of water-marsh interspersion to provide the most benefit for fishery species.

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.

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.

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.

We examined the distribution of nekton across the marsh landscape using a 1-m2 drop sampler to compare nekton densities across three different salinity zones (intermediate, brackish, saline), three pond sizes (diameter 40 msmall, 250300 mmedium, 750 mlarge), and two habitat types (pond, adjacent marsh) in the Barataria Bay Estuary, Louisiana. Nekton assemblages of ponds and the adjacent marsh appeared to be structured by the responses of individual species to the estuarine salinity gradient at the landscape scale and to pond habitat attributes locally. Our results indicate that ponds in the brackish and saline zones are more important nursery areas for most fishery species than ponds in the intermediate zone. Medium and large ponds supported higher densities of most species than small ponds. Most species of nekton were associated with vegetation structure, and individuals of these species were either concentrated among plant stems at the marsh edge or within submerged aquatic vegetation in ponds.

This data contains fish and invertebrate counts, weights, and measurements important to identify and describe the relationship between fishery productivity and the coastal environment. Specifically, to examine nursery utilization of estuarine marshes by fishery species in relation to differences in salinity among sites. 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.

Measured fine-scale distributions of nekton on the vegetated marsh surface using drop samplers and utilized these patterns to estimate population size. Natant decapod crustaceans were most abundant in the marsh, while densities of juvenile brown shrimp, white shrimp, and blue crabs were highest 1-m from the marsh edge interface, declining rapidly towards open water. Developed regression models to describe fine-scale density patterns and used this information to estimate the population of natant decapods in a highly fragmented marsh in the Galveston Bay system.