Coral Reefs

, Volume 35, Issue 1, pp 273–284

The ups and downs of coral reef fishes: the genetic characteristics of a formerly severely overfished but currently recovering Nassau grouper fish spawning aggregation

  • A. M. Bernard
  • K. A. Feldheim
  • R. Nemeth
  • E. Kadison
  • J. Blondeau
  • B. X. Semmens
  • M. S. Shivji
Report

DOI: 10.1007/s00338-015-1370-3

Cite this article as:
Bernard, A.M., Feldheim, K.A., Nemeth, R. et al. Coral Reefs (2016) 35: 273. doi:10.1007/s00338-015-1370-3

Abstract

The Nassau grouper (Epinephelus striatus) has sustained large declines across its distribution, including extirpation of many of its fish spawning aggregations (FSAs). Within US Virgin Islands (USVI) waters, Nassau grouper FSAs were overfished until their disappearance in the 1970s and 1980s. In the early 2000s, however, Nassau grouper were found gathering at Grammanik Bank, USVI, a mesophotic coral reef adjacent to one of the extinct aggregation sites, and regulatory protective measures were implemented to protect this fledgling FSA. The population genetic dynamics of this rapid FSA deterioration followed by protection-facilitated, incipient recovery are unknown. We addressed two objectives: (1) we explored which factors (i.e., local vs. external recruitment) might be key in shaping the USVI FSA recovery; and (2) we examined the consequences of severe past overfishing on this FSA’s current genetic status. We genotyped individuals (15 microsatellites) from the USVI FSA comprising three successive spawning years (2008–2010), as well as individuals from a much larger, presumably less impacted, Nassau grouper FSA in the Cayman Islands, to assess their comparative population dynamics. No population structure was detected between the USVI and Cayman FSAs (FST = −0.0004); however, a temporally waning, genetic bottleneck signal was detected in the USVI FSA. Parentage analysis failed to identify any parent–offspring matches between USVI FSA adults and nearby juveniles, and relatedness analysis showed low levels of genetic relatedness among USVI FSA individuals. Genetic diversity across USVI FSA temporal collections was relatively high, and no marked differences were found between the USVI and Cayman FSAs. These collective results suggest that external recruitment is an important driver of the USVI FSA recovery. Furthermore, despite an apparent genetic bottleneck, the genetic diversity of USVI Nassau grouper has not been severely compromised. Our findings also provide a baseline for future genetic monitoring of the nascent USVI aggregation.

Keywords

Nassau grouper Microsatellite Fish spawning aggregation Bottleneck Population recovery 

Supplementary material

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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • A. M. Bernard
    • 1
  • K. A. Feldheim
    • 2
  • R. Nemeth
    • 3
  • E. Kadison
    • 3
  • J. Blondeau
    • 3
  • B. X. Semmens
    • 4
    • 5
  • M. S. Shivji
    • 1
  1. 1.The National Coral Reef Institute and Guy Harvey Research Institute, Oceanographic CenterNova Southeastern UniversityDania BeachUSA
  2. 2.Pritzker Laboratory for Molecular Systematics and EvolutionField MuseumChicagoUSA
  3. 3.Center for Marine and Environmental StudiesUniversity of the Virgin IslandsSt. ThomasUS Virgin Islands, USA
  4. 4.Scripps Institution of OceanographyUniversity of California, San DiegoLa JollaUSA
  5. 5.Reef Environmental Education Foundation (REEF)Key LargoUSA

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