Cobia don’t have a swim bladder. That means they sink to the bottom when not actively swimming. Cobia will settle on the bottom, such as behind a large ray, and rise up when the ray begins moving again.
Much of cobia migratory patterns are likely onshore to offshore, or a combination of north to south and onshore to offshore. Based on satellite tags, some cobia head to Gulf Stream waters during winter (for warmth). Cobia prefer waters above 68 degrees F.
Researchers detected multiple satellite-tagged fish diving to depths deeper than 200 meters (656 feet). That means fish not only head to deeper offshore waters, but also use bottom habitat there.
In some locations, cobia use estuaries to spawn. Port Royal Sound, South Carolina, and the Chesapeake Bay are examples. There are likely more undiscovered spawning estuaries too.
Much of what we know about cobia movement comes from a series of acoustic telemetry projects from Virginia through the Gulf. Hundreds of cobia have been surgically implanted with acoustic transmitters. These transmitters emit an individualized ping every 90 seconds that can be recorded if an implanted cobia comes within range of a listening station or receiver. These listening stations are located throughout the South Atlantic, Gulf, and beyond in mostly inshore and nearshore locations.
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Cobia cover a lot of ground, which makes them such good candidates for acoustic telemetry. One individual fish tagged off Cape Canaveral, Florida, was detected on 85 different receivers. Other cobia were detected at dozens of locations. One fish even ventured across the Gulf Stream from Florida and was detected off Grand Bahama.
—Matt Perkinson, with Fishing Outreach and Education at the South Carolina Department of Natural Resources
