‘Grouper Moon’ shines on schools


It was a science lesson with a difference, broadcast live from beneath the waves with thousands of endangered fish in attendance. 

Schoolchildren from across the Cayman Islands and the Bahamas tuned in this week to a series of webcasts from Little Cayman’s famous Nassau grouper aggregation site.  

Researchers who have been documenting fish numbers and behavior at a handful of aggregations sites around the Cayman Islands for more than a decade briefed children on their work using special underwater cameras and microphones. 

During the winter full moon, in either January or February, the normally solitary and territorial Nassau grouper travel long distances to gather in one spot – most dramatically at a protected spawning site off the west end of Little Cayman. 

Throughout the spawning period, smaller groups of between five and 40 fish rush together to spiral upward into the water column releasing clouds of sperm and eggs into the sea. 

Brice Semmens, a scientist from Reef Environmental Education Foundation, who presented the underwater webcasts, said students were enthused to witness science in action. 

“As they explore the aggregation with me, the immediacy and reality of the experience really touches them. Put simply, we are giving students their first diving experience – and it happens to be with thousands of huge, endangered reef fish.”  

Christy Pattengill-Semmens, also of REEF, said schoolchildren should feel proud of the work being done in the Cayman Islands. 
“The Nassau grouper is such an icon for the Caribbean, and it’s really a source of pride to have one of the healthiest grouper populations in the Caribbean,” she said. 

The work of the Grouper Moon research project – a collaboration between the Department of Environment and REEF – has led to fishing restrictions at the aggregation sites and an increase in numbers of the endangered fish. 

Bradley Johnson, research officer with the DoE, said the numbers for this year were not as high as in the past. But he believes there is likely to be a “split-spawn” over January and February because of the timing of the full moons in 2014. 

The Grouper Moon Project had its beginnings in 2002 after an estimated 2,000 fish were taken from the Little Cayman site, which was not protected at the time.  

To reduce fishing pressure and allow the Department of Environment to monitor the site, Cayman’s Marine Conservation Board implemented an alternate-year fishing strategy.  

In 2003, based on Nassau grouper population numbers, an eight-year ban was introduced on fishing the aggregations. The ban was extended in late 2011 for a further eight years.  

The research team is currently involved in acoustic fish tagging, genetic studies, satellite tracking of drifting baby grouper, juvenile habitat research and educational outreach. 

“Our aim is to support best management practices for Nassau grouper,” said Ms Pattengill-Semmens. “The whole idea behind the Grouper Moon Project is to better understand the Nassau grouper aggregation and then provide the best information the Cayman Islands government so they can better manage the species.” 


The Nassau grouper spawns just after the winter full moon in January or February. – PHOTO: ALEX MUSTARD

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