Date of Award

7-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean Engineering and Marine Sciences

First Advisor

Spencer Fire

Second Advisor

Glenn Miller

Third Advisor

Karen Kim Guisbert

Fourth Advisor

Wendy Noke Durden

Abstract

Common bottlenose dolphins (Tursiops truncatus truncatus) in the Indian River Lagoon (IRL) have experienced four Unusual Mortality Events (UMEs). This stock is considered immunocompromised and is routinely subjected to persistent anthropogenic stressors such as fishing gear entanglement, vessel strikes, contaminants, and harmful algal blooms. Previous body condition assessments of this stock have involved invasive capture-release examinations or subjective methods using lateral body images. To improve precision, we investigated the use of photogrammetry data collected from noninvasive unmanned aircraft systems (UAS) combined with models developed from capture-release data to estimate morphometric parameters and subsequently determine the body condition of these free-swimming ecosystem sentinels. Lateral body condition scoring (BCS) and photo-identification methods were simultaneously used to compare body condition measurements and to categorize measurements (ideal, underweight, or emaciated). A total of 29 dolphins were measured using MorphoMetrix. Body Area Index (BAI) measurements were not significantly different across age class (p = 0.314) and BCS (p = 0.232). Estimated Body Mass Index (BMI) measurements ranged BMI varied significantly by age class (p < 0.001) but not by BCS (p = 0.101). Lateral body condition evaluation resulted in four ideal dolphins, twenty-four underweight dolphins, and one emaciated lactating female. Future efforts should be made to increase sample size and efficiency of these methods. This study provides a foundation for future noninvasive UAS studies on bottlenose dolphins.

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