applied ecology,, nassau grouper, grouper moonproject, marine conservation, sustainable fishing, There is no more iconic Caribbean fish than the Nassau Grouper, boldly striped, seemingly unafraid and friendly toward divers and unfortunately very tasty. It was once found in the tens of thousands throughout the Caribbean, however due to unsustainable fishing practices its numbers have diminished to the point where it is now classified as “endangered”.  (photo –

The Grouper’s reproductive process is partly to blame for this. During the winter’s full moons the groupers, often migrating hundreds of miles, gather in great numbers at specific locations, to spawn.


Nassau Grouper Safety Is Not In Numbers

chuck knapp, shedd aquarium, nassau grouper, grouper spawning, sustainable fishing, marine conservation, bahamas, grand caymanDuring these spawning aggregations, millions of eggs, fertilized in the water are released to drift in the current for up to 40 days. The tiny larval fish eventually seek safety in coastal seagrass and mangrove forests. The problem occurs because these spawning aggregations reoccur in precisely the same locations each year and once these are known to the local fishers it is easy pickings. Historically thousands of Groupers have been caught during these few days when they are most vulnerable and often before they can reproduce, decimating not only the current generation but also the next generation with the result that populations have declined precipitously. (photo – Chuck Knapp, Shedd Aquarium)



Marine Protected Area on Little Cayman Offers Hope

nassau grouper spawning color, little cayman island, marine conservation, illegal fishing, protected marine areaIn recent years, tens of thousands of Nassau grouper reproduced successfully at five sites around the Cayman Islands.  But following the same pattern of unsustainable fishing that decimated some 50 spawning sites throughout the Caribbean and Bahamas, has resulted in only one Caymanian site remaining viable.  At the eastern end of Little Cayman there is a marine protected area where fishing for Nassau Grouper is banned from November through March and much needed research into the sustainability of the species is on-going. Did you know that Nassau Groupers change colors and patterns during their spawning process.

Over the last thirteen years The Key Largo-based Reef Environmental Education Foundation (REEF) and the Cayman Department of the Environment have been conducting the “Grouper Moon Project” – counting fish; implanting them with acoustic tags; collecting larvae and observing patterns of reproduction. “Our goal is to get the population here in Little Cayman up to 10,000 and repopulate the other islands and bring this fishery back to its former glory,” Dr. Guy Harvey said. After viewing Reef’s research the Marine Conservation Board of the Cayman Islands extended the fishing ban on Grouper to 2019.


Local Fisherman will Benefit from these Efforts

nassau grouper, nassau grouper spawning, marine conservation, little cayman, marine protected area“Local fishermen need to realize that these conservation measures will benefit all user groups in the years to come,” Dr. Harvey concluded. “Once the Nassau grouper population recovers it can then be managed and fished within the restrictions of new catch limits, but the spawning brood stock must be protected forever.”

Another important aspect of keeping the grouper population healthy is to serve as a predator to the invasive, non-native lionfish, which has spread throughout the Caribbean and have annihilated several species of juvenile reef fish. In 2012 Dr. Harvey helped produce a documentary film that focuses on the plight of the Nassau Grouper and the important research being carried out. See Changing Seas: Grouper Moon below.


Richard Branson Diving in Grouper Spawn and Loving It

Richard Branson of Virgin Air recently had an exhilarating dive with Dr. Guy Harvey during the Nassau Grouper spawn off Little Cayman. Join with Richard and share his experience.

Richard and Guy with the Nassau Groupers at Little Cayman. from George Schellenger on Vimeo.


The Grouper Moon is Almost Here, Join Us

the grouper moon project, nassau grouper spawning, marine protected area, marine conservation,There is an extensive Grouper Education Program that brings Live-Feed video chats directly into local school rooms, from underwater with Grouper Moon researchers . Students can watch spawning aggregations, listen on a hydrophone to grouper vocalizations and talk directly to researchers underwater. This is all part of a program to educate the local population to the importance of protecting and preserving this unique marine resource  You can visit: YouTube channel to view live streaming and archived sessions.

Plus see our recent post on a Girl’s Science Club project to solve the problem of marine by-catch, see: SOS: Girls’ Science Club Seeks Feedback, Insight from Marine Experts


Visit Blue Ocean for Related Articles:

Read about the Shedd Aquarium’s efforts in the Bahamas:

Injured Dolphin Knows where to go for Help

Fishing Ban Extended at One of the Last Spawning Areas for the Nassau Grouper | Guy Harvey Sportswear Blog

Diving the Grouper Moon

Grouper Moon Project Works With Dr. Guy Harvey To Produce Documentary | Reef Environmental Education Foundation (REEF)

Grouper Moon Project – Protecting a Caribbean Icon | Reef Environmental Education Foundation (REEF)

Film and Conservation: “The Mystery of the Grouper Moon” Documentary – Repeating Islands


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