Study on the Nassau Grouper Underway

Dr Yvonne Sadovy of the University of Hong Kong and the Caribbean Fisheries Management Council

The viability of the Nassau grouper is under the microscope. Once a commonly landed commercial species in the Caribbean, it is now considered to be threatened. 

“It’s at the most extreme end of vulnerability,” said Dr Yvonne Sadovy of the University of Hong Kong and the Caribbean Fisheries Management Council. Dr. Sadovy is in The Bahamas to assist with a study of the Nassau grouper. She was welcomed Monday by Agriculture and Marine Resources Minister Larry Cartwright. 

The harvesting of groupers, valued as a very tasty coral reef fish, is prohibited in The Bahamas between December 1 and March 1. 

There is a strong consensus amongst biologists that unless something is done within the region, the populations of groupers will continue to decline with all the losses associated with that, Dr Sadovy warned. 

Already the World Conservation Union has listed the grouper as “endangered”. Over exploitation and habitat loss are among the major threats to the viability of groupers.    

“Until relatively recently there was a general perception, globally, that the seas are so big and there are so many fish in the sea that we can’t possibly over exploit them. We now know - we have plenty of examples that we can – that we can even threaten commercially important species,” said Dr Sadovy. 

A part of her work was to document the status of aggregating species like the Nassau grouper. 

“If aggregations are exploited they can decline very quickly,” she said. “The great majority are decreasing, a few are gone, several are stable partly because of management, and a few are increasing.” 

And, of all the aggregating species, the Nassau grouper appears to be “the most vulnerable,” she said. That is so due to its biology. 

Because groupers are long-lived, it takes a long time for them to recover or replace themselves. It takes a long time for them to reach sexual maturation during which time they are exposed to harvesting. 

Based on projections, if nothing is done there would be “a complete collapse” within eight years, she said. Because landings have continued to go down, over the last 20 years there have been an increasing number of management interventions and regulations. 

Increasingly a focus of interest with respect to that protection is on the protection of the aggregations, said Dr Sadovy. One of the most important measures for these more vulnerable types of species “is a real need for effort controls.” 

“Reef fisheries are not capable of withstanding the massive pressures to which they are being subjected. So, there is an over all acceptance of licensing. For exploited aggregations, some kind of special protection of aggregation sites is an option. This can very well be reinforced by a sales ban.” 

In many places gear control is being discussed. As the amount of product landed goes down, various types of gear are being used to increase yield. The use of spear and scuba equipment at night is of concern, she said.