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Study Says Changes Needed to Protect Conch in The Bahamas

January 08, 2019

Dr. Andy Kough dives to find large, football-sized conch shells on the ocean floor in the Bahamas.

Queen conch, Lobatus gigas, is a marine snail with an iconic shell that serves as a culinary staple in The Bahamas. However, thousands of years of exploitation in the greater Caribbean region has had clear impacts on conch abundances. If queen conch populations in The Bahamas continue to decline, scientists warn the inevitable end to economically viable conch fishing if actions are not taken to allow the conch stocks to recover. Published in the scientific journal, Reviews in Fisheries Science and Aquaculture, the study documents population changes associated with heavy fishing and provides recommendations to rehabilitate the Bahamian queen conch stock based on surveys and evaluations conducted by Community Conch and Chicago’s Shedd Aquarium.

“The collapse of this fishery for a nation like The Bahamas would be devastating culturally, economically and ecologically,” said Dr. Allan Stoner, senior scientist at Community Conch, a non-profit organization that aims to protect queen conch in The Bahamas using science, outreach and community engagement. “While the queen conch fishery is currently at risk, government actions can help recover the Bahamian stocks. This research study provides scientific evidence of its decline directly through fishing, while also offering a range of solutions that are both feasible and significant.”

The published research study analyzed surveys of queen conch populations in The Bahamas between 2009 and 2017 to explore how fishing pressure impacts population structure and the ability for the conch to reproduce. To do so, scientists collected data on how many conch were present at a given survey site (density) and their age (thickness of their shell). They surveyed nearly 1 million square meters of The Bahamas and measured more than 3,000 conch at 42 survey sites throughout the archipelago. Survey data was compared with historic data that dates back as far as 1987.

Three key research findings:

  • The number of adult conch decreased in direct proportion to increases in fishing pressure, and the populations in fishing grounds have become younger with time.
  • Densities of legal-to-harvest queen conch are now far below the well-established minimum threshold for reproductive success, except in the most remote areas.
  • A viable fishery for queen conch in The Bahamas might only last another 10 to 15 years unless significant measures are taken to reduce fishing pressure.

“As the abundances of queen conch decreases, the life history of these slow-moving snails begins to work against them,” said Dr. Andy Kough, research biologist at Shedd Aquarium in Chicago. “Conch need to be in close enough proximity to each other to find a mate, reproduce and replenish the population. The removal of young animals who have never had the chance to reproduce, combined with serial depletion in areas where there were previously thriving stocks, paints a grim outlook and demands urgent action before we all lose a beloved snail species and tasty treat.”

Queen conch has long been imperiled across its Caribbean range. As a result of heavy fishing and habitat loss, in 1992, the international trade of queen conch fell under the protections of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) – an international treaty to prevent species from becoming endangered or extinct. Over time, there’s been an increase in fishing regulations where conch live, although the regulations vary substantially in the 30 nations where conch are distributed. For example, in Florida, there’s been a complete moratorium on conch harvesting for more than 30 years; however, Florida’s conch population still has not rebounded to a commercially harvestable level.

The Bahamas is one of only a few nations where substantial populations of queen conch remain and where a large volume of the conch meats and products are exported. But, The Bahamas is unlike most Caribbean nations in that it has no closed season for conch fishing.

“The results of our study shine an alarming light on the state of queen conch in The Bahamas. As such, regulations need to be implemented to prevent the looming devastation of a fishery collapse,” said Kough. “The primary requirements for rebuilding a rapidly declining queen conch stock is to reduce fishing mortality and to rebuild densities of spawning stocks. It would be incredible to see numbers return to the abundances found throughout the archipelago in the past, yet only found in a few isolated corners today.”   

“The results of our study shine an alarming light on the state of queen conch in The Bahamas. As such, regulations need to be implemented to prevent the looming devastation of a fishery collapse.”

Dr. Andy Kough, research biologist at Shedd Aquarium

The study provides nine fisheries management recommendations to allow the stock to recover from exploitation. Recommendations include establishing a size limit for legal harvest of queen conch based on a shell lip thickness of 15 millimeters (which indicates maturity and thus reproductive ability) while also enforcing landing and trade of conch in the shell (enabling better enforcement) and endingexport of queen conch from The Bahamas. Barring success with any of the above, the study states that it may be necessary to close the conch fishery entirely for a period of at least five years.

“Unfortunately, any management measures designed to reduce fishing mortality will impact the near-term ability of conch fishers to make a living wage, and it will be important to assist displaced fishers in finding other sources of income,” said Stoner. “But as in all overfishing cases, survival of a long-term queen conch fishing industry will hinge upon management with a long view for sustainability.”

For more information about queen conch and Community Conch, visit And for more information on Shedd Aquarium’s conch research studies, visit Shedd’s website. 

PHOTOS: High resolution photos of queen conch from the Bahamas are available for download:
©Shedd Aquarium/Sam Cejtin

VIDEO: High resolution b-roll footage of Shedd Aquarium’s queen conch research is available for download:
©Shedd Aquarium/Sam Cejtin