A Comparative Assessment of Gulf Estuarine Systems (CAGES)
HARMON BROWN, THOMAS J. MINELLO, GEOFFEREY A. MATTHEWS, MARK FISHER, EVAN J. ANDERSON, RALF REIDEL, and DEBBIE L. LEFFLER
ABSTRACT -Estuaries are important in supporting much of the fishery production in the Gulf of Mexico, but this support appears to vary widely among different estuarine systems. The main objective of this project was to assess variability among estuaries in supporting fishery species and other abundant nekton. The project is part of a larger effort of the National Marine Fisheries Service Galveston Laboratory to develop a Comparative Assessment of Gulf Estuarine Systems (CAGES). The nekton abundance data summarized in this report are available at http://data.gcoos.org.
This cooperative study with state natural resources agencies was designed to use fishery independent monitoring data and compare historical catches from 4.9-m and 6.1-m trawl surveys. This report provides an assessment of the abundance, length frequencies, and biomass of 14 species of fish and four species of decapod crustaceans that were either abundant in the samples or economically important. The most abundant species in the analysis include bay anchovy, Atlantic croaker, spot, and brown shrimp. Other fishery species of particular interest include Gulf menhaden, white shrimp, pink shrimp, blue crab, spotted seatrout, southern flounder, and red drum. While the years analyzed varied among states, samples from most estuaries were available and analyzed for the years 1986 to 2005. The 24 estuaries analyzed were identified using the Estuarine and Coastal Drainage Areas delineated by the U. S. Geological Survey and listed in NOAA’s Coastal Assessment Framework http://coastalgeospatial.noaa.gov/data_gis.html.
Comparisons of abundance or biomass between estuaries should be made with care. Even within states, the selection of sampling sites may affect such comparisons. In Texas and in Florida, the randomization of sampling sites within estuaries can make these comparisons meaningful, if an adequate number of samples was collected. Within Louisiana, Mississippi, and Alabama, the location and distribution of fixed sampling stations should be considered when making comparisons among estuaries. Comparisons of nekton abundance or biomass in estuaries of different states also need to account for differences in sampling gear and size frequency distributions.
The authors are with the Southeast Fisheries Science Center, National Marine Fisheries Service, Texas Parks and Wildlife Department, University of Southern Mississippi and the Florida Fish and Wildlife Conservation Commission. (Corresponding author: firstname.lastname@example.org).