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Pandemic-Enabled Research Reveals Changes to Grouper and Lobster Populations in The Bahamas

Increase in Threatened Grouper Spotlights the Potential for Population Recovery with the Establishment of Conservation Measures

October 06, 2022

A school of large grouper fish swim along a reef.

Photo by: Photo by Tom Sparke, Grouper Moon Project 2020, Little Cayman

New research published in Aquatic Conservation: Marine and Freshwater Ecosystems by scientists at Shedd Aquarium in Chicago with support from the Bahamas National Trust explores the impact of reduced human activity during the pandemic on two species native to the tourism-rich Bahamian archipelago—threatened Nassau grouper (Epinephelus striatus) and sustainable Caribbean spiny lobster (Panulirus argus). As documented in the study, grouper populations saw a short-term surge in their population numbers during the pandemic. In contrast, lobster populations saw no change, as might be expected with a sustainably-managed fishery species. Both species had higher numbers and reached larger body sizes within a Marine Protected Area (MPA). The study indicates that, when there are reduced human interactions and presence—as is the case with conservation management practices like marine protected areas or during a pandemic—populations can recover rapidly.

“There’s not a one-path-fits-all approach to help a range of species recover from overfishing or other human impacts, but we know that many species benefit from long-term spatial conservation management,” said Dr. Andy Kough, research biologist at Shedd Aquarium. “The results of our study tell us that marine protected areas benefit both ecosystems and fisheries, and they show that short term changes in policy can have a positive impact on species recovery.”

Nassau grouper are a threatened species in The Bahamas whose numbers have been greatly reduced by overfishing. Grouper move long distances to breed so, while they are migrating during the winter, The Bahamas protects them with a closed season so that they can produce the next generation. On the other hand, spiny lobsters are thriving in The Bahamas. Lobsters are a certified-sustainable commercial fishery by the Marine Stewardship Council (MSC) and have had a stable population for many years.

To study these important species, the team of scientists conducted repeated SCUBA surveys at popular dive sites in The Bahamas during the highest month of tourist visitation in the year prior to the pandemic (2019) and then again within weeks of the country re-opening while visitors were still largely absent. Pairs of divers searched reefs that provide shelter for spiny lobster while also looking for Nassau grouper.

The study’s results revealed that lobster abundance did not significantly change during the pandemic, yet flighty and rare groupers were more often observed in the MPA in a year when tourists were absent. In the protected waters of an MPA, where fishing has long been banned but tourists are allowed, both species were significantly larger, lobster were always more abundant and more groupers were observed during the anthropause.

“Beautiful reefs and healthy populations of grouper and lobsters benefit all Bahamians,” said Lindy Knowles, study coauthor and senior science officer at the Bahamas National Trust. “As we welcome visitors back into our country, we must also understand how national parks and fisheries regulations replenish our oceans to enhance tourism well into the future.”

As tourism returns to The Bahamas, Bahamas officials and scientists shared the need to reflect on the study’s results, which show how fast populations can increase during a pause in human activity.

“Alongside negative impacts on human life, the COVID-19 pandemic caused a deeper appreciation and greater use of natural spaces around the globe that should be leveraged into biodiversity conservation planning and a more green recovery,” said Kough. “The hardships of the pandemic highlight the importance of maintaining spatial conservation practices as a draw for continued tourism in the future.”

The study, “Anthropause shows differential influence of tourism and a no-take reserve on the abundance and size of two fished species,” can be read online from Aquatic Conservation: Marine and Freshwater Ecosystems at: https://doi.org/10.1002/aqc.3856.

For more information about Caribbean spiny lobster and Nassau grouper, visit the Bahamas National Trust’s https://bnt.bs/what-we-do/science/. And for more information on Shedd Aquarium’s lobster and grouper research studies visit Shedd’s website: https://www.sheddaquarium.org/care-and-conservation/shedd-research.