The Great Red Snapper Count: Direct Visual Counts

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Publication Number: P3283

This publication describes the direct visual counts phase of the Great Red Snapper Count, which is a 2-year research project to estimate the abundance of red snapper in the U.S. Gulf of Mexico.

Underwater view of many red snapper swimming around a remotely operated vehicle (ROV). A cable attaches the ROV to a controller onboard the research vessel. — Photo by the Center for Sportfish Science and Conservation

Where will scientists count red snapper?

Counts will be performed across the U.S. Gulf of Mexico at various habitat types. For more details, see our Habitat Classification video and MSU Extension Publication 3282 The Great Red Snapper Count: Habitat Classification.

What types of equipment will scientists use onboard research vessels?

Scientists will use two types of camera equipment: remotely operated vehicles (ROVs) and towed cameras.
An ROV is deployed from a stationary vessel and driven by an operator in a specific pattern, much like the operation of a remote-controlled car.
A towed camera is pulled behind a research vessel at a constant speed and altitude above the seafloor, along a predetermined path.
Both camera types will record video footage to be analyzed later.

A remotely operated vehicle (ROV) resting on a boat with the ocean in the background. The ROV is a small, motorized device with an action camera mounted on top.

A towed camera rests on a boat with rigging, flotation devices, ocean, and blue sky visible in the background. The towed camera is a large piece of equipment. — An ROV, the VideoRay Pro 4 (top), and a towed camera, the Camera-Based Assessment Survey System (C-BASS) (bottom), are used for direct visual counts. Photos by the Center for Sportfish Science and Conservation (top) and the Continental Shelf Characterization, Assessment, and Mapping Project (C-SCAMP) (bottom)

Why do scientists need to use two different types of equipment?

ROVs are best for surveying discrete artificial and natural habitats.
Towed cameras are best for surveying large expanses of sand and mud bottom.

How will scientists collect fish count data from the video footage?

The videos from the two types of cameras will be transferred to laboratory computers and analyzed.
First, scientists will count the number of red snapper in each ROV and towed camera video.
Then, these counts will be converted to density estimates, which will yield abundance estimates.
In areas with poor visibility or very large structures, bioacoustic sonar (imagine a “fish finder”) will be used with ROV surveys to confirm red snapper abundance estimates.

This independent study is being conducted by a leading team of red snapper scientists from across the Gulf of Mexico and beyond:

This publication was supported by the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration under NOAA Award NA16OAR4170181, the Mississippi -Alabama Sea Grant Consortium, and the Mississippi State University Extension Service. The views expressed herein do not necessarily reflect the views of any of these organizations.

Publication 3283 (POD-10-18)

MASGP-18-019-03

By Amanda E. Jefferson, Extension Associate, and J. Marcus Drymon, PhD, Assistant Extension Professor, Coastal Research and Extension Center.

Produced by Agricultural Communications.

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Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. GARY B. JACKSON, Director

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