A Family Business: Genomic Assessment of Decades-Long Ecotourism Provisioning on Southern Stingrays (Hypanus americanus)

Author

• Shelby G. Pawlikowski, Nova Southeastern UniversityFollow

Defense Date

8-4-2026

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Biological Sciences

First Advisor

Mahmood Shivji

Second Advisor

Andrea Bernard

Third Advisor

Kevin Feldheim

Fourth Advisor

John Swenson

Keywords

3RAD, elasmobranch, relatedness, population genomics, stingray ecotourism

Abstract

The Stingray Sandbar site in Grand Cayman hosts an iconic, year-round, largely resident aggregation of southern stingrays (Hypanus americanus), resulting from four decades of daily ecotourism-feeding operations. Primarily large, mature females dominate the aggregation, and their residency can span over a decade with high fidelity to the sandbar’s surrounding waters. Behavioral shifts observed in the aggregation have been well documented due to extensive sampling of the aggregation since 2002, yet the genomic impacts of this high-volume ecotourism operation remain unexamined. Since mating has been observed here, there is concern that this multi-decadal human-provisioning may be altering the aggregation’s evolutionary trajectory. I used restriction site-associated DNA sequencing to compare genome-wide variation in the aggregation stingrays and two non-provisioned stingray populations (Bimini, Bahamas and Belize). Stingrays from each of the geographic locations comprise distinct genetic populations. Relatedness analysis detected 97 first order and 188 second order relatives in the Stingray Sandbar aggregation, which was notably higher than the number of relatives identified in Bimini. Pedigree reconstruction revealed three generations of stingrays captured during the 21-year sampling period and one prominent family group. Minimal inbreeding, lack of substructure within Grand Cayman, and similar genetic diversity estimates to unfed Caribbean stingrays suggests ecotourism feeding is not adversely affecting the aggregation’s genetic health. However, provided the genetic and geographic isolation of Grand Cayman stingrays from other Caribbean sites and high number of relatives in the aggregation, continued genetic monitoring is recommended to support the Caymanian ecotourism industry while promoting long-term sustainable management of the iconic aggregation.

NSUWorks Citation

Shelby G. Pawlikowski. 2026. A Family Business: Genomic Assessment of Decades-Long Ecotourism Provisioning on Southern Stingrays (Hypanus americanus). Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (245)
https://nsuworks.nova.edu/hcas_etd_all/245.