Environmental Biology of Fishes

, Volume 97, Issue 9, pp 1057–1065 | Cite as

Kin structure and social organization in the spotted eagle ray, Aetobatus narinari, off coastal Sarasota, FL

  • Jennifer Newby
  • Tanya Darden
  • Kim Bassos-Hull
  • Andrew M. Shedlock


Observations of elasmobranchs in groups suggest sociality in sharks and rays. However we currently lack a strong understanding of social structure and the role kinship has in structuring group organization in cartilaginous fishes. The spotted eagle ray, Aetobatus narinari (Euphrasen, 1790) frequents the shallow waters near Sarasota, FL, often in pairs or groups suggesting a social component to their behavior. In the present study, eight eagle ray-specific microsatellite markers were used to investigate relatedness in A. narinari groups, and used to determine if kin structure contributed to group organization. Using regression-based and maximum-likelihood approaches, relatedness was quantified and compared within and among groups of juveniles, and adults in mixed sex and same sex groups. Results showed a lack of kin-structured sociality in A. narinari, suggesting factors apart from relatedness shape social interactions among spotted eagle rays in the near-shore waters of Sarasota, FL. Our results add to the limited amount of published literature on elasmobranch kinship, which are important for understanding implications of anthropogenic disturbance on genetic variability for coastal populations.


Elasmobranch genetics Spotted eagle ray Microsatellite genotyping Gulf of Mexico Social behavior Kinship 



This project was supported by a College of Charleston Graduate Program in Marine Biology Genomics Fellowship and Slocum-Lunz Foundation Grant awarded to JN and by a College of Charleston Biology Department Faculty Research and Development Grant awarded to AMS. Approval by the IACUC committee was obtained before conducting research on the spotted eagle rays in this study. We thank the members of the Darden research group (SCDNR) for genotyping support. Allan Strand, Erik Sotka (Grice Marine Lab) and Anna Sellas (California Academy of Sciences) provided helpful discussions regarding experimental design, genetic sampling and statistical analysis. Tissue samples were obtained through the Spotted Eagle Ray Conservation Program at the Mote Marine Laboratory with support from the National Aquarium in Baltimore, Georgia Aquarium, Disney Worldwide Conservation Foundation, and Save Our Seas Foundation. We thank Peter Hull, Dean Dougherty, Greg Byrd, Krystan Wilkinson and the summer internship program at MML.


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Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Jennifer Newby
    • 1
  • Tanya Darden
    • 2
  • Kim Bassos-Hull
    • 3
  • Andrew M. Shedlock
    • 1
  1. 1.College of Charleston Biology DepartmentCharlestonUSA
  2. 2.Marine Resources Research InstituteHollings Marine LabCharlestonUSA
  3. 3.The Center for Shark ResearchMote Marine LaboratorySarasotaUSA

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