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Summer and Fall Groundfish Surveys in the Gulf of Mexico

NOAA Fisheries and partners conduct annual groundfish surveys to provide biological data and information for stock assessments in the Gulf of Mexico.

Southeast

Table of Contents

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A team of scientists in hard hats and personal floatation devices handles a large green net on the deck of a research vessel at sea
A team of scientists retrieves a trawl net full of fish samples from the fall groundfish survey on the R/V Oregon II. Credit: NOAA Fisheries/Hannah Shahmoradi

The Southeast Fisheries Science Center, in coordination with the Southeast Area Monitoring and Assessment Program (SEAMAP), plans and conducts the Summer and Fall Groundfish Surveys. We use these data to produce a time series of catch and biological data for multiple fish and shrimp species in the Gulf of Mexico. These data are provided to stock assessment scientists and fisheries managers to support the assessment and sustainable management of Gulf marine fisheries. 

NOAA Fisheries conducts the sampling with the states of Louisiana, Mississippi, Alabama and Florida. The summer survey was initiated in 1982 and the fall survey in 1986. 

Objectives 

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A scientist stands in a laboratory processing samples of small fish
A scientist on the groundfish survey sampling and collecting data on different species. Credit: NOAA Fisheries

The objectives of these groundfish surveys are to:

  • Sample the northern Gulf of Mexico for data concerning the distribution and abundance of groundfish and invertebrate populations to aid in stock assessments 
  • Collect measurements and biological samples of fish to be used in life history studies 
  • Conduct Conductivity, Temperature, and Depth (CTD) scans to profile the water column’s temperature, conductivity (salinity), transmissivity, dissolved oxygen concentrations, and fluorometry (fluorescence) 
  • Provide processed profiles from the CTD instruments to NOAA’s National Center for Environmental Information and other researchers for further application 

Sampling Design 

The current survey design was implemented in 2009 for the summer survey and 2008 for the fall survey. Sampling occurs across the northern Gulf, divided into different spatial regions based on shrimp statistical zones. The depth zones are set at 30–120 feet and 120–360 feet.

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A team of scientists in hard hats and personal floatation devices handles a large green net on the deck of a research vessel at sea
Trawl net with catch at haul back. Credit: NOAA Fisheries

Sampling Gear

A standard 42-foot semi-balloon trawl is used to collect samples during these surveys. The trawl  has 8-foot by 40-inch wooden doors and is towed across the seafloor at 2.5 knots. CTD instruments gather environmental data throughout the water column at each sampling station. They are equipped with:

  • Dissolved oxygen sensor
  • Transmissometer (to measure turbidity, a measurement of the amount of light that is scattered by material within the water column)
  • Fluorometer (to measure the amount of light emitted)

Sampling Universe

We conduct the surveys in all trawlable bottom habitats in the northern Gulf of Mexico from Dry Tortugas, Florida to Brownsville, Texas. A trawlable bottom habitat for the survey is considered to be one that does not contain natural reefs, artificial structures, or oil rigs. They are areas less than 30 feet or greater than 360 feet deep. We do not sample marine protected areas, habitats of particular concern, or fish havens to prevent damage to these sensitive habitats.

A map of the Gulf of Mexico with federal waters out to 360 feet highlighted in yellow, labeled "SEAMAP Summer and Fall Groundfish Survey Area"
The Summer and Fall Groundfish Survey combined collects data for over 40 days in the Northern Gulf of Mexico per year, which is critical for fisheries managers. Credit: NOAA Fisheries

Survey Facts

  • Location: northern Gulf of Mexico from Dry Tortugas, Florida to Brownsville, Texas
  • Timeframe: 
    • Summer survey: June and July
    • Fall survey: October and November
  • Time series: 
    • Summer Survey: 1982 to present
    • Fall Survey: 1986 to present
  • Depth range: 9 to 110 meters (approximately 30 to 361 feet)
  • Target days at sea: 
    • NOAA Fisheries: approximately 40 days per season at sea 
    • State partners: approximately 21 days per season
  • Target number of stations (NOAA Fisheries and partners combined): between 300 and 350 per season
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a bunch of small silver with with pinkish tails and faded bars and spots in a white basket
Juvenile red snapper of various sizes in a basket. Credit: NOAA Fisheries

Data Collected

Biological 

  • Catch species composition
  • Abundance
  • Weight
  • Sex
  • Maturity
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A white basket is filled with brown shrimp
Northern brown shrimp (Farfantepenaeus aztecus) from our first trawl station. Credit: NOAA Fisheries/Hannah Shahmoradi

Environmental

  • Air temperature 
  • Barometric pressure 
  • Surface water temperature 
  • Wind speed 
  • Wind direction

Water Column Profile 

  • Temperature
  • Conductivity (salinity)
  • Depth
  • Transmissivity (turbidity)
  • Dissolved oxygen concentrations 
  • Fluorometry

Biological Data

The primary focus for the summer and fall groundfish survey is to collect biological data including catch species composition, abundance, weight, sex, and maturity. We catch as many as 82 different species in a single trawl. Some of the most common species collected in the survey are red snapper, northern brown shrimp, Atlantic croaker, and Gulf flounder.

Data Applications

These data are used for a variety of purposes, including:

  • Providing indices of abundance for stock assessments
  • Monitoring size and distribution of penaeid shrimp
  • Collecting environmental data, and facilitating life history studies

The Summer and Fall Groundfish Surveys help us monitor the health of the Gulf of Mexico ecosystem and support sustainable fisheries management. 

More Information

More Information

Last updated by Southeast Fisheries Science Center on 03/14/2024

Gulf of Mexico