Defense Date
8-6-2026
Document Type
Thesis
Degree Type
Master of Science
Degree Name
Marine Science
First Advisor
Susana Caballero Ph.D.
Second Advisor
Ramon Bonfil Ph.D.
Third Advisor
Cindy Gonzalez Ph.D.
Fourth Advisor
Derek Burkholder Ph.D.
Keywords
environmental DNA (eDNA), metabarcoding, elasmobranchs, Mexico, nursery habitats, marine conservation
Abstract
Elasmobranchs play a critical ecological role in marine environments, yet many populations worldwide remain poorly known and monitored. This is particularly true in Mexico despite its high biodiversity and ongoing fishing pressures. Traditional monitoring methods, such as commercial fisheries and fishery-independent surveys using longlines or nets, are often limited, leaving important knowledge gaps. Previous studies have shown that environmental DNA (eDNA), small traces of DNA left behind in the water column from feces, skin, or mucus, is a transformative, non-invasive tool for detecting elasmobranch presence and diversity across marine ecosystems.
This project used eDNA metabarcoding to detect and identify elasmobranch species off the coast of Quintana Roo, Mexico, with a focus on areas of high biodiversity and potential nursery habitats. Additional objectives included comparing eDNA results with existing fisheries-independent data (BRUVs and longline surveys), evaluating the effectiveness and limitations of eDNA for monitoring elasmobranch populations, analyzing changes in species presence over time, and identifying potential nursery habitats when paired with BRUVs and longline surveys. Only six of the 65 sequenced samples produced elasmobranch detections, all corresponding to bonnethead sharks (Sphyrna tiburo) from Bahía de la Ascensión. Limited detection success likely reflects methodological and biological factors, including low eDNA concentrations, primer bias, limited filtration volume, and variation in eDNA shedding and persistence. Although detection success was limited, these results demonstrate the potential of eDNA metabarcoding to complement traditional monitoring methods while emphasizing the need for methodological refinements to improve detection of elasmobranch communities
NSUWorks Citation
Sara T. Norment. 2026. Using Environmental DNA (eDNA) as a Tool to Detect Sharks and Rays Along the Coast of Quintana Roo, Mexico. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (243)
https://nsuworks.nova.edu/hcas_etd_all/243.