New research published in Aquatic Conservation: Marine and Freshwater Ecosystems by scientists at the University of Texas at Austin and Shedd Aquarium in Chicago provides direct evidence of a thriving population of queen conch (Lobatus gigas) inhabiting a remote bank in The Bahamas. The scientifically described stock at Cay Sal Bank is one of the three highest abundances of queen conch found in the wider Caribbean in the last few decades. The secluded population, distant from most fishers’ reach, is optimally placed to replenish depleted conch populations over much of the archipelago and needs to be protected through conservation measures.
“Cay Sal was logistically challenging to survey and we were not sure what we would find since we were surveying shallow areas with evidence of fishing,” said Philip Souza Jr., Ph.D. student at the University of Texas and lead author of the study. “We were astounded to discover densities matching the old-time fishing tales that I had heard from time spent visiting family and friends on Great Exuma.”
Queen conchs are an economic and cultural keystone in The Bahamas as the nation’s second-largest fishery and treasured culinary dish. However, previous research has suggested that conch populations in The Bahamas have decreased dramatically and are overfished throughout their range. The Bahamas have implemented some fishing regulations and established marine protected areas, however, a lack of baseline population data—or a pristine natural population to use as a model—makes it difficult to determine if these measures are effective, according to scientists. And without evidence, it is difficult to highlight their importance to policymakers.
“We discovered that Cay Sal Bank had tremendously abundant conch, loads of breeding and plenty of recruitment,” said Andy Kough, Ph.D., research biologist at Shedd Aquarium and co-author of the study. “We are hopeful that evidence of a robust and natural conch refuge may fuel future legislative protection specific to the bank.”
Utilizing Shedd Aquarium’s 80-foot research vessel, the R/V Coral Reef II, Souza and Kough led a research team in 118 SCUBA dives to survey the population on the Cay Sal Bank during queen conch mating season in June 2017. Conch abundance data was collected and analyzed using several methods to estimate the overall stock size.
“We are hopeful that evidence of a robust and natural conch refuge may fuel future legislative protection specific to the bank.”Andy Kough, Ph.D., research biologist at Shedd Aquarium
The stock estimates were all in agreement that the Cay Sal Bank population numbers were one of the highest surveyed in the Caribbean. The shells’ length and thickness were also measured to estimate the relative age of the population, revealing some of the thickest shells—thus, oldest conch—surveyed in The Bahamas.
The uninhabited Cay Sal Bank is the westernmost part of the Bahamian archipelago. According to the study, the high abundance of queen conch described may be the result of remoteness and relief from heavy fishing pressures. Biophysical models suggest that the currents passing over Cay Sal Bank transport larval conch to other parts of the archipelago, thereby replenishing overfished stocks. Based on its high population of conch and its unique oceanographic position, the researchers say Cay Sal Bank should be protected.
“A protected and productive breeding population on Cay Sal is ideally placed to send the next generation of conch elsewhere in The Bahamas and help replenish declining stocks,” said Kough. “Further research will show the broader impact of Cay Sal, but the presence of a healthy population was a breath of fresh air for conch-servation.”
Recently, in an effort to protect 20% of The Bahamas’ marine and coastal habitat by 2020, Cay Sal Bank has been added to a list of marine protected areas. Additionally, the Bahamas National Trust and The Nature Conservancy launched the collaborative, “Bahamas Protected” campaign to improve management and public awareness of these sites. However, to protect the iconic Caribbean snails and local fishing economy, researchers have urged the commonwealth to employ a spatially specific “no-take” reserve or other measures to protect queen conch on Cay Sal Bank. Media reports compiled in the article and past research have revealed that poaching represents the greatest threat to these remote Bahamian habitats.
In the United States, queen conch are a candidate species for the U.S. Endangered Species Act. The U.S. Fish and Wildlife Service has tracked and restricted trade of queen conch as a protected species since 1992.
To read the published research study, “Queen Conch Lobatus gigas population estimates and age structure suggest a potential natural refuge on the Cay Sal Bank, The Bahamas,” visit https://doi.org/10.1002/aqc.3348.
For more information about queen conch, visit the Bahamas National Trust’s educational Conchservation website. And for more information on Shedd Aquarium’s conch research studies, visit Shedd’s website.
VISUALS: Photos of Shedd Aquarium’s queen conch research are available for download here: https://personal.filesanywhere.com/fs/v.aspx?v=8e6a678d5e6771b1b068.
Credit: ©Shedd Aquarium/Sam Cejtin
Video of Shedd Aquarium’s queen conch research is available here: https://www.youtube.com/watch?v=_EYW-9qPjZo.
Credit: ©Shedd Aquarium