Bahamas: Tracking Nassau Groupers

Shedd Aquarium has a long history of marine research and conservation efforts in the Bahamas, a country we’ve highlighted in our exhibits since we opened in 1930. A new multiyear study focusing on Nassau groupers deepens our commitment to the country’s fragile ecosystems and the people who depend on them.

Growing up to a substantial 4 feet and 50 pounds, this grouper is one of the most important food fishes throughout the Caribbean and West Indies. It is also one of the most rapidly disappearing.

How to find a group of groupers
The project takes the study to the Bahamas in December and January, in the dead of Chicago’s winter but also at the height of the groupers’ breeding season. The study focuses on the large groups, called spawning aggregations, in which these wide-ranging fish gather to reproduce.

The predictable appearance of these aggregations at the same sites at the same times — around the winter full moons — makes the groupers easy targets for fishermen. The once-a-year opportunity also encourages overfishing, with heavy tolls on the large mature ones needed to replenish the population. But it also enables researchers to locate them and implant tiny acoustic transmitters, or tags, for tracking them. 

RigIn April, a crew consisting of Shedd Fishes department experts, researchers from the Bahamas National Trust and divers from the University of Miami and the Florida Department of Environmental Protection placed a dozen acoustic telemetry monitors along 140 miles of the continental shelf off the eastern coast of Andros, the largest island in the Bahamas. Past studies revealed that the groupers migrate along the edge of the shelf.

Sitting in about 100 feet of water, each monitor floats on a 10-foot tether from an anchor of concrete blocks, where it can detect tagged groupers within a 150-meter radius if there are no obstructions to the signal such as large coral heads.

This summer, the team is back in Andros, tagging adult Nassau groupers on their home reefs. The surgically implanted transmitters, about the size of a AA battery, last for several years, so the team should be able to learn the groupers' migration patterns, spawning behaviors and habitat preferences during several breeding seasons.

The findings will be used by the Bahamas Department of Marine Resources to create a science-based management plan to protect this ecologically and economically important endangered species.


The Bahamas

About the team

Learn more about the conservation research team.

You can help!

You don’t have to be a scuba diver or a scientist to assist with Dr. Kristine’s Nassau grouper research. Your gift to Shedd’s annual fund will help support this and Shedd’s other conservation programs around the world.

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