Grouper spawning number ‘healthy’

Scientists and conservationists gathered in five offshore sites on the Cayman Islands last week to monitor the annual grouper spawning. 

James Gibb, research officer at the Department of Environment, who is involved in the monitoring of the Nassau Grouper that gather in their thousands every year to drop eggs, said the numbers this year “looked very healthy and, hopefully, in the next few years, it will get better and better”. 

“Everyone was more than satisfied by how it all looked,” he said. 

The exact population numbers that appeared at the five aggregation sites are not yet known, Mr. Gibb said, as the data is still be analysed, but scientists at one Little Cayman site estimated between 3,000 and 5,000 groupers were present there.  

The spawning period this year was longer than usual, lasting four nights. 

“I think the biggest difference this year from any previous year in the 11 or 12 years of studies was that there were four nights of spawning on Little Cayman,” said marine conservationist Guy Harvey. “Normally, it’s two nights or occasionally three. That represents an increase in terms of numbers of eggs put out there to repopulate.” 


Since 2008 

Along with the Department of Environment, the Reef Environmental Education Foundation, known as REEF, Oregon State University and the crew of the Glen Ellen yacht are involved in the monitoring of the annual spawning, which only happens during a full moon. These organisations have been involved in the monitoring project, called the Grouper Moon Project, since 2005.  

The Glen Ellen crew were on hand in Cayman Brac to help track and monitor the spawning site there. They were checking how reported overfishing on the Island had impacted the grouper population between this year’s spawning season and the last time the site at the eastern part of the island was monitored five years ago. 

Despite it being illegal to fish for groupers in the designated spawning sites during spawning season, Mr. Harvey said there had been reports of fishermen catching large grouper nearby at the Grand Cayman site in East End. “That defeats the whole process,” he said.  


No legislation 

Mr. Harvey lamented that legislation offering protection to groupers has not been passed by lawmakers. The proposed legislation includes the implementation of a closed season for grouper fishing between November and March each year, a permanent ban on fishing at grouper spawning sites and modifying existing catch limits for groupers at certain times of the year. 

“This isn’t an anti-fishing move… It will allow the population to build up,” said Mr. Harvey, adding that banning fishing of grouper during their breeding and spawning season will enable the stocks to repopulate to levels historically seen in Cayman. 

While all the spawning action happens underwater, more than 100 feet down, landlubbers this year were able to get a look at what was going on. Live video feeds of the spawning at one of the Little Cayman sites were broadcast live online and pupils from Spot Bay Primary School and Cayman Prep were able to ask scientists from REEF questions about the spawning online. 

This is the second year REEF, using a grant from Disney, has teamed up with schools in the Cayman Islands to help educate the younger generations about grouper spawning and of the importance of protecting the fish and their spawning sites. 

Grouper are solitary and territorial creatures that get together only in large groups, known as aggregations, during a winter full moon when they are about to spawn. Thousands of the fish aggregate at a single spot and throughout the spawning period, smaller groups of between five to 40 fish rush together to spiral upwards into the water column releasing clouds of sperm and eggs into the sea. 


Groupers gather in their thousands during a winter full moon to spawn. – PHOTO: Still from Guy Harvey video


  1. The fishing for grouper has to be monitored carefully at nights. People are doing deep water fishing at those times and catching the groupers by the hundreds to sell at restaurants. I think the ban need to be epanded to more months.

Comments are closed.