This paper presents exciting results from the Grouper Moon Project, documenting conservation success for endangered Nassau Grouper. Results of the analysis showed that on both Little Cayman and Cayman Brac in the Cayman Islands, Nassau Grouper spawning aggregations have more than tripled in response to adaptive management by the Cayman Islands government over a decade. On Little Cayman, the aggregating population grew from around 1,200 fish in 2009 to over 7,000 in 2018. The study used a two-pronged approach that included tagging and video census data for monitoring and counting Nassau Grouper populations in an effort to more accurately estimate annual numbers of fish in the population, and thus provide insight into the effects of ongoing conservation efforts. While many governments have enacted regional or seasonal fishing closures in an attempt to allow recovery of overfished stocks of aggregating reef fishes, this is the first study to provide evidence that these measures can be successful across multiple decades.

The paper was authored by a collaborative team of researchers from Reef Environmental Education Foundation (REEF), Cayman Islands Department of Environment, Scripps Institution of Oceanography, and Oregon State University. The Grouper Moon Project represents nearly 20 years of research, monitoring, and outreach efforts, coordinated by REEF and Cayman Islands Department of Environment, in collaboration with researchers from Scripps Institution of Oceanography and Oregon State University. It is the Caribbean’s oldest continuous grouper spawning aggregation research program, and represents one of the most advanced, multi-faceted tropical fisheries research programs in the world. Due to overfishing during spawning, Nassau Grouper have suffered region-wide stock collapse. By the 1980s large aggregations had all but disappeared from the Caribbean region. Of the remaining aggregations, few contained more than 1,000 individuals and the species is currently listed as critically endangered by the International Union for Conservation of Nature. The aggregation on Littl Cayman is the largest known for this endangered reef fish.