Relationships between Queen Conch Larval Biology and Recruitment, Connectivity, and Fishery Management

Abstract

The queen conch (Aliger gigas) is an important fishery resource species in the Caribbean region, increasingly threatened by overharvest. The species’ life history is characterized by density-dependent reproduction, benthic egg masses, and a 2-4-week planktotrophic period with potential for long-distance dispersal. This review focuses on veliger growth, development, and settlement, especially as related to environmental variables, and larval duration and behavior relevant to transport. More than 3000 plankton collections for queen conch made throughout the region show that most veligers occur in the upper water column during the warmest season, with evidence for a positive association between abundance of late-stage veligers and subsequent abundance of juveniles in nursery grounds. Biophysical models based upon the best information on veliger duration and vertical movement yield predictions on population connectivity and can be used in design for networks of marine protected areas. While the earliest genetic studies suggested an open panmictic Caribbean population, more recent molecular genetic results show that populations exhibit a continuum-like structure, and self-recruitment occurs in certain localities. The current state of knowledge of early life history and connectivity for queen conch is discussed in terms of recruitment potential, climate change, and management for sustainable fisheries.

Keywords:

• Marine conservation
• larval transport
• molluscan ecology
• fishery management
• veliger development

Acknowledgments

Long-term funding for the early field and laboratory studies related to queen conch veligers in The Bahamas and Florida was provided by NOAA’s National Undersea Research Program. Other support was provided by the Florida Department of Environmental Protection, the Looe Key National Marine Sanctuary, and The Bahamas National Trust in the early years of our field work. John G. Shedd Aquarium and the non-profit organization Community Conch provided crucial support over the last decade, and some of the most recent studies on veliger development and metamorphosis were made possible by funding from the Hummingbird Cay Foundation and the Saltonstall-Kennedy Grant Program (NOAA) to M. Davis. We are grateful to all of the students, interns, technicians, and volunteers that assisted the authors in field and laboratory studies from the 1980s to present. Hazel Oxenford, Dalila Aldana-Aranda, Gabriel Delgado, and Richard Appeldoorn all assisted in providing published and unpublished veliger abundance data and contributed recent discussions on queen conch ecology. We thank two anonymous reviewers and the editor for constructive criticism.

Notes

1 The taxonomy of Atlantic conch species has been the subject of much discussion Simone 2005, Latiolais et al. 2006, Landau et al. 2008, Maxwell et al. 2020), and recent revisions have led to the genus names Eustrombus, Lobatus, and Aliger for queen conch. While Strombus gigas was the accepted name for queen conch for many decades and in a vast literature for the species, the most recent recommendation is Aliger gigas.

2 Export of queen conch from The Bahamas was suspended in 2022.

3 The reader should refer to Garr (2012) for the full array of experiments conducted to test the effects of copper and zinc on queen conch veligers and their food sources.

4 To date there have been no experimental studies whatsoever on queen conch veliger predation and only inferences can be made for the type III survivorship curves observed.

5 Davis and Stoner (1994) provide a long list of the epiphytic diatoms that were associated with the surfaces of the two test substrata.

6 Readers interested in details associated with surveys in Mexico should refer to thesis research conducted by de Jesús-Navarrete (1999) and Chavez-Villegas (2011).

7 All of these species were classified under the genus Strombus when the veliger descriptions were published by Davis et al. (1993).

8 For details related to handling and analyzing queen conch statoliths see Davis (1993) and Grana-Raffucci and Appeldoorn (1997).