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 How to Use

Explore the Louisiana Fisheries Mapping Application, containing fisheries-independent data displaying the Relative Abundance for species of interest.

STEP 1: The mapping application works with the ArcGIS Viewer for Flex. Click on the map of Louisiana Coastal Study Areas to access the mapping application.

STEP 2: Select a gear type and species of interest in the mapping application to view the spatial distribution of the species. An expandable list allows the user to view relative abundance data by sampling stations or by average across sampling grids. Other selection choices include data sampled across all years or by season.

STEP 3: Select a hydrological parameter of interest (salinity, temperature, turbidity) and expand the list to choose seasonal averages by grid.


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 Louisiana Fisheries Mapping Application

LA Coastal Fisheries Mapping Application

 

About the Data

The Louisiana Department of Wildlife and Fisheries (LDWF) Marine Fisheries Division uses a number of sampling gears for fisheries-independent monitoring of finfish and shellfish communities. The gears include: 1) bag seines for collecting smaller organisms in near shore environments; 2) trawls for collecting organisms found on or near the open bay bottoms; 3) gill nets for catching larger fish near shore; 4) trammel nets for catching larger fish near shore; and 5) oyster dredges for sampling the oyster reef community (data not included in this mapping application).

Collected data include spatial and temporal information describing the sample location and time, collection gear information, hydrological data (e.g. dissolved oxygen, water temperature, and salinity), weather conditions, species caught, and number of each species captured. Data are collected at the same location each year.  Data for selected species are displayed here in terms of relative abundance (RA), calculated as the catch of a particular species in a sample divided by the total number of animals captured in that sample.

For monitoring purposes, the Louisiana coast is divided into 7 Coastal Study Areas (CSA's) (described in the Louisiana Marine Fisheries Division Field Procedures Manual, 2002). The associated mapping application can be used to view fisheries independent data for selected species found in Louisiana's 7 Coastal Study Areas:

1. CSA I: Bordered on the east by the Mississippi state line and on the south by Bayou Terre aux Boeufs, including such major water bodies as Chandeleur and Mississippi Sounds, and Lakes Borgne, Pontchartrain, and Maurepas.

2. CSA II: Bisected by the Mississippi River with Bayou Terre aux Boeufs on the east, extending to Grand Bayou on the west. Some major water bodies found on the eastern side of the Mississippi River include Breton Sound, Black Bay, Bay Gardene, Little Lake, Bay Crabe, American Bay, California Bay, Quarantine Bay and Grand Bay. Bay Adams, Bay Jacques, Skipjack Bay, Sandy Point Bay and Bay Lanaux are found on the western side of the Mississippi River.

3. CSA III: Includes Barataria and Caminada Bays and Little Lake. Grand Bayou is the eastern boundary and Bayou Lafourche is the western boundary.

4. CSA IV: Includes the Timbalier and Terrebonne Bay complex along with Lake Pelto. It is bounded on the east by Bayou Lafourche and on the west by Bayou Sale.

5. CSA V: Defined by Bayou Sale on the east and Atchafalaya River/Point au Fer Island on the west. Major water bodies in this area are Caillou Bay, Caillou Lake, Lake Mechant, Lake Decade, and Four League Bay.

6. CSA VI: Extends from Atchafalaya River on the east to Freshwater Bayou on the west. Large water bodies in this area include Vermilion Bay, West Cote Blanche Bay, East Cote Blanche Bay, and Atchafalaya Bay.

7. CSA VII: Encompasses the region from Freshwater Bayou, located in Vermilion Parish, westward to the Louisiana/Texas state line. Estuaries located within CSA VII include the Rockefeller Wildlife Refuge complex, the Mermentau River Basin, Calcasieu Lake, Lake Charles, Prien Lake, and Sabine Lake.

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 Species Spotlight

Image courtesy of Texas Parks and Wildlife[Photo: Texas Parks and Wildlife]

Blue Crab
Callinectes sapidus

Description: The blue crab is a swimming crab and a member of the Portunidae family. Blue crabs grow up to 8 in. wide and 4 in. long, weighing 1-2 lbs. The crab gets its name from the bright blue color of its legs. The prominent front legs, or claws, are used as pinchers, while the remaining four pairs are utilized for walking and swimming. The blue crab is dark green on its back (carapace), with a white abdomen.

Life History: Blue crabs are opportunistic feeders; eating fishes, oysters, clams, snails shrimp, worms and other crabs. Blue crabs mate from February to November, after which females migrate to higher salinity waters to spawn. Blue crabs must shed their exoskeletons to grow and females can only mate during their final molt.

Habitat: Blue crabs are bottom-dwellers and require a range of salinity conditions for growth. Thus, blue crabs can be found in the open ocean (up to 120 ft deep) as well as inland estuaries.

Distribution: Blue crabs live along the east coasts of North and South America (north to Novia Scotia and south to Uruguay). They are also present along the coasts of France, Denmark, and Holland.

Status: The blue crab is a commercially important species of crab, with fisheries throughout the US coast. Coastal water currents and abundance of predators play an imporant role in the yearly variation of blue crab populations.

Resources:

Texas Parks and Wildlife Department

South Carolina Department of Natural  

 

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