Louisiana Marsh Management Plan 1995
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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.
Gulf Shrimp System
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Gulf of Mexico Shrimp Landings - This data set contains catch (landed catch) and effort for fishing trips made by the larger vessels that fish near and offshore for the various species of shrimp in the Gulf of Mexico. The data collection procedures for the catch/effort data for the large vessels consist of two parts. The landings statistics (i.e., quantity, value, etc.) are collected from the seafood dealers after the trips are unloaded whereas, the data on fishing effort (gear, fishing duration) and area are collected by interviews with the captain or crew while the trip is being unloaded.
Vallisneria 2003-2004
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We compared nekton use of Vallisneria americana Michx. (submerged aquatic vegetation, SAV) with marsh shoreline vegetation and subtidal nonvegetated bottom (SNB) using a 1-m2 drop sampler in the oligohaline area of Barataria Bay, Louisiana. Mean densities of most abundant species were significantly different among six habitat types. Harris mud crab Rhithropanopeus harrisii, Ohio shrimp Macrobrachium ohione, blue crab Callinectes sapidus, daggerblade grass shrimp Palaemonetes pugio, white shrimp Litopenaeus setiferus (fall), rainwater killifish Lucania parva, naked goby Gobiosoma bosc, code goby Gobiosoma robustum (fall), speckled worm eel Myrophis punctatus (fall), and gulf pipefish Syngnathus scovelli (spring), were much more abundant, and species richness also was greater, in Vallisneria than over SNB. Vallisneria supported densities of most species that were similar to those in marsh vegetation, although naked goby and gulf pipefish were more abundant in Vallisneria, and speckled worm eel and saltmarsh topminnow Fundulus jenkinsi were more abundant in marsh. Within the Vallisneria bed, densities of Harris mud crab, rainwater killifish, and speckled worm eel were higher at sites near the marsh (SAV Inside Edge) than at sites more distant from the marsh (SAV Outside Edge), and Ohio shrimp (fall) densities were higher in the interior of the bed than along the edges. The mean size of blue crab was larger in marsh than Vallisneria and larger in Vallisneria than SNB. White shrimp did not differ in size among habitat types. Vallisneria beds may provide an important nursery habitat for young blue crab and white shrimp that use oligohaline estuarine areas. These SAV beds can provide an alternative structural habitat to emergent vegetation during periods of low water, because Vallisneria occurs in the subtidal and generally persists throughout the year on the Gulf coast. Species whose young thrive in low-salinity waters and also depend on structure would benefit most from Vallisneria habitat in estuaries.