데이터셋 상세
미국
Myrtle Grove 2002
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.
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연관 데이터
Laguna Madre System 1995-1998
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Study compared densities of nekton, benthos, and seagrass among newly deposited dredged sediments and nearby and distant natural seagrass sites over a three year period. Recovery of seagrass and nekton communities from dredged material placement was predicted to take from 4-8 years.
Poplar Island Environmental Restoration Project Nekton Data
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The Poplar Island Environmental Restoration Project (PIERP) is a large scale 1,800 acres restoration project located in mid Chesapeake Bay. Fishery collections are conducted three times per year to assess fishery use of restored wetlands. Collection gear types used included fyke net, gill net, crab pot, and otter trawl all used to assess forage and predator fish abundances. Survey data is used to assess the functions of the restored PIERP wetlands, and adjacent shallow water habitats influenced by the PIERP, relative to reference habitats and to pre-construction conditions. Data from these collections will also help assess restored wetland maturity and its ability to maintain stable resident and predator fish populations.
San Antonio Bay 1986-1989
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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.
Grand Isle 1988
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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.
Houston Ship Channel 1993-1994
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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.
Sabine National Wildlife Refuge 1999
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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.
Meta-analysis of estuarine nurseries
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Densities of juvenile fishery species and other animals (all generally 100 mm total length) were summarized for shallow estuarine areas along coastal Texas and Louisiana. The purpose was to identify where these species live (delineate their habitat) and to analyze density patterns within habitats that would be useful in distinguishing EFH. Analyses were restricted to data collected with enclosure drop sampler techniques that have been shown to provide comparable density estimates among highly diverse shallow-water areas. Habitat types evaluated included Spartina alterniflora marsh edge (SAME), mixed-vegetation marsh edge, inner marsh (5 m from open water), submerged aquatic vegetation (SAV), oyster reefs, and shallow nonvegetated bottom (SNB). All habitat types are likely essential for some fishery species. The analysis highlighted many of the challenges confronted in determining habitat-use patterns and emphasized the need for additional systematic sampling to examine geographic variability in habitat use and to examine distribution patterns within habitats. However, in addition to analyses of intra-habitat densities, the identification of EFH requires information on functional relationships between fishery species and habitat characteristics. In a second paper, the nursery role of salt marshes was examined for transient nekton by searching the global literature for data on density, growth, and survival of juvenile fishes and decapod crustaceans in marsh areas. We analyzed density data from 32 studies conducted world-wide using a meta-analyses to test hypotheses. Based on fish density, habitat types could be ranked from highest to lowest as: seagrass vegetated marsh edge, nonvegetated marsh, open water, macroalgae, oyster reefs vegetated inner marsh. However, patterns of habitat use varied among the various fishes and decapod crustaceans represented.
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.
Terracing at Pierce Marsh in Galveston Bay 2001-2002
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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.
Southern Gulf of St. Lawrence Ecosystem Research Vessel Survey (September Survey, NAFO Division 4T) Dataset
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PURPOSE: The research survey provides a fisheries-independent source of information about all marine living organisms that are captured by the fishing trawl used to obtain samples in the southern Gulf of St. Lawrence. DESCRIPTION: Tow, catch, length frequency, and biological information for fish caught during the annual September research vessel trawl surveys in the southern Gulf of St. Lawrence (NAFO Division 4T). Abundance indices and spatial distribution patterns of commercial and non-commercial groundfish. The catch data that appear in this dataset SHOULD NOT BE USED FOR ECOLOGICAL ANALYSES INVOLVING CATCH RATES. Important factors such as vessel, fishing gear and diurnal periods must be accounted for to use these data in analyses. Please contact the data custodians if you are interested in using this data for any kind of ecological analyses involving catch rates. PARAMETERS COLLECTED: abundance estimates (ecological); distribution (ecological); species counts (ecological); gear (fishing); vessel information (fishing); point (spatial) NOTES ON QUALITY CONTROL: Scientific names listed in the survey species list have been mapped to recognized standards - marine taxa have been mapped to the World Register of Marine Species (WoRMS) using their online taxon match tool. All sampling locations were plotted on a map to perform a visual check confirming that the latitude and longitude coordinates were within the described sampling area. In 2003, because of a fire aboard the Alfred Needler, the Wilfred Templeman was used for the survey. However, no comparative fishing experiments have been conducted between the Alfred Needler and the Wilfred Templeman. We are therefore unable to integrate the indices derived for 2003 to the remainder of the survey time-series. SAMPLING METHODS: Sampling Method: Consult the "Protocols for research vessel cruises within the Gulf Region (dermersal fish) (1970-1980)" report, link provided in the citations list. USE LIMITATION: To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.