Defense Date

4-30-2026

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

David W. Kerstetter

Second Advisor

Susana Caballero Gaitan

Third Advisor

George Duncan

Keywords

Trophic Ecology, DNA Metabarcoding, Diet Composition, PSIRI, Elasmobranch, Indian River Lagoon

Abstract

The Indian River Lagoon is a brackish estuarine ecosystem along the Atlantic coast of Florida where bluntnose (Hypanus say) and Atlantic (Hypanus sabinus) stingrays are common. Life-history parameters of these species are poorly known, including diet. Traditional diet research used visual identification of ingested prey in the stomach, but soft-bodied prey consumed by many batoids tend to be quickly digested. For this study, two techniques were applied to better quantify prey items and assimilation for the two stingray species: stomach content analysis (SCA) and DNA metabarcoding. Of the 200-specimen set, diet of 167 stingrays was examined from H. say (n=84) and H. sabinus (n= 83) using SCA. Polychaetes, shrimps, crabs, brittle stars, and small fishes were the most common prey findings with varying %PSIRI values. These values were greatest for polychaetes across all stratified data of H. say akin to decapods for H. sabinus. DNA metabarcoding reflected SCA prey items with greater prey diversity detected for H. sabinus than H. say. Detection of dietary trends of H. say and H. sabinus like seasonal, ontogenetic, and sex-based diet preferences is vital for understanding general knowledge of these two stingray species and the overall Indian River Lagoon ecosystem health. It was found that both stingray species have a highly diverse diet consisting of benthic invertebrates and small teleost fishes that have indicated to slightly vary with season, maturity, and sex for H. say and to be consistent across such for H. sabinus.

ORCID ID

0009-0005-4304-1923

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Available for download on Tuesday, November 24, 2026

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