MEPS 573:177-189 (2017)  -  DOI: https://doi.org/10.3354/meps12163

Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring

Andrew S. Kough1,*, Heather Cronin2, Rachel Skubel3, Carolyn A. Belak4, Allan W. Stoner5

1Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium, Chicago, IL 60605, USA
2AIS Inc., 14 Barnabas Road, Marion, MA 02738, USA
3Abess Center for Ecosystem Science and Policy, University of Miami, Miami, FL 33146, USA
4California Department of Fish and Wildlife, Stockton, CA 95206, USA
5Community Conch, Lopez Island, WA 98261, USA
*Corresponding author:

ABSTRACT: Marine Protected Areas (MPAs) are designed to conserve and preserve the ecosystems and cultural resources of the ocean. In theory, protected populations flourish, replenish adjacent regions, and are self-sustaining. However, describing the efficacy of MPAs requires long-term monitoring. Queen conch Lobatus gigas are iconic Caribbean denizens with populations that have been decimated by overfishing and are slow to rebound due to density-dependent breeding. The Exuma Cays Land and Sea Park (ECLSP) is a well-enforced, no-take, old, and large MPA. Surveys in 1994, 2011, and 2016 were used to track changes in the abundance, size, and age structure of conch within the park. Statistical models suggested that abundances of adults in 50 km of repeated towed-observer surveys had declined by 71% in 2016 relative to 2011. Further, the remaining conch populations were associated with tidal channels, and these model results agreed with independent observations in 40 km of expanded survey area. Measurements of shell lip thickness, an estimator of relative age, showed an increase relative to 1994 with the greatest effect in 2016, indicating senescence. The ECLSP population appears to be slowly dying of old age, and an early life history process has been altered. Upstream populations have been heavily fished while habitats within the park remain productive, suggesting that low local retention and a lack of exogenous larval sources are driving the decline. A network of MPAs encompassing the entire life cycle and dispersal envelope of targeted organisms is needed for proper conch conservation. Surveys focused on tidal channels could locate candidate upstream populations of conch.


KEY WORDS: Queen conch · Marine protected area · Benthic survey · Senescence · Size · Age


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Cite this article as: Kough AS, Cronin H, Skubel R, Belak CA, Stoner AW (2017) Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring. Mar Ecol Prog Ser 573:177-189. https://doi.org/10.3354/meps12163

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