Episode 403: Grouper Moon

Join researchers from the Reef Environmental Education Foundation and the Cayman Islands Department of Environment as they study one of the last great reproductive populations of Nassau grouper. Normally a solitary species, during the winter full moons Nassau grouper travel, sometimes over great distances, to "group" together and spawn. While most of the known spawning sites in the Caribbean have been fished out over the years, the west end of Little Cayman in the Cayman Islands is home to the largest known reproductive spawning aggregation of this endangered species.

Experts

Meet the experts featured in this episode.

Episode Photos

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Little Cayman, Cayman Islands.

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A Nassau grouper.

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Nassau grouper are curious and friendly fish.

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Scientists counting the fish at the aggregation site.

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A certain percentage of grouper are tagged with a Floy streamer tag (foreground), which helps scientists determine the size of the population.

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A Nassau grouper hovering over a sponge.

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Videographer Sean Hickey films Steve Gittings, Ph.D. as he is counting fish.

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A scientist observes the fish at the aggregation.

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These days, Nassau grouper spawning aggregations have drastically declined due to overfishing. Little Cayman is home to one of the last healthy known aggregations of this kind.

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Christy Pattengill-Semmens, Ph.D., Scott Heppell, Ph.D., Bradley Johnson, Brice Semmens, Ph.D. and Guy Harvey, Ph.D. ready for the next dive on the aggregation site.

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From left to right: Bradley Johnson, Brice Semmens, Ph.D., and Steve Gittings, Ph.D. talk about their last dive.

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Videographer Sean Hickey films the action on the boat, while Christy Pattengill-Semmens, Ph.D., Steve Gittings, Ph.D., and Scott Heppell, Ph.D. have a chat.

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Bradley Johnson tries to catch a juvenile Nassau grouper in shallow water.

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Videographer Jeremy Nicholson films Bradley Johnson as he tries to catch a juvenile Nassau grouper.

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Juvenile Nassau grouper are hard to catch. Scientists take small fin clips from the fish for DNA analysis.

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Videographer Jeremy Nicholson films the juvenile Nassau grouper in the net.

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A juvenile Nassau grouper.

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Juvenile Nassau grouper live in shallow water until they are large enough to move out to the coral reef.

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A juvenile Nassau grouper peeks out of its hiding hole. Unlike their larger cousins, the little grouper are very wary of people.

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From left to right: Scott Heppell, Ph.D., Alexis Johnson, Brice Semmens, Ph.D., and Christy Pattengill-Semmens, Ph.D.

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Changing Seas Videographers Jeremy Nicholson (left) and Sean Hickey (right).

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Scott Heppell, Ph.D. collected fish eggs while the Nassau grouper were spawning.

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A close-up of Nassau grouper eggs.

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Little Cayman’s famous Bloody Bay wall.

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Two Nassau grouper at the spawning aggregation.

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Sunset on beautiful Little Cayman.

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Students at Cayman Prep and High School learning about Nassau grouper.

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Series Producer Alexa Elliott takes a water break between interviews on Grand Cayman.

Special Thanks:

Cobalt Coast Dive Resort

P.O. Box 159
18-A Sea Fan Drive
West Bay, Grand Cayman
Cayman Islands, KY1-1401

Image Credits

Changing Seas would like to thank the following individuals and institutions who kindly allowed their footage, images and other media to be used in this production:

Brice Semmens
Huw Evans
Joshua Stewart
Leslie Whaylen Clift
Kirsten Luke McCord
Reef Environmental Education Foundation

Scott Heppell
Heppell Lab - Oregon State University

Phil Bush
Cayman Islands Department of Environment

Special Thanks:

Gina Matthews
Cayman Islands Dept. of Tourism

Reef Divers
Little Cayman Beach Resort
Cayman Islands

Little Cayman, Cayman Islands
Peter Hillenbrand
Southern Cross Club

Delwin McLaughlin

Keith Neale

Kevin Jackson

Web Extras

How do scientists study fish at the aggregation site?

Grouper Moon Web Chat

Episode 403: Grouper Moon

Experts

Christy Pattengill-Semmens, Ph.D.

Brice Semmens, Ph.D.

Scott Heppell, Ph.D.

Steve Gittings, Ph.D.

Bradley Johnson

Gina Ebanks-Petrie

Timothy Austin

Bruce Eldemire

Hon. Mark Scotland

Verity Redrup

Chris Bodden

Alexis Jackson

Special Thanks:

Image Credits

Special Thanks:

Web Extras

Funding for this episode of Changing Seas was provided by: