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ThesisCC BY-NC V4.0, Embargoed Access, Embargo ends: 10-Dec-2026
Dissertation
Population Genetics and Trophic Ecology of Two Cetacean Species in the Ecuadorian Whale Sanctuary, the Galapagos Archipelago
Doctor of Philosophy, University of the Sunshine Coast, Queensland
2026
DOI:
https://doi.org/10.25907/01016
Abstract
Cetaceans are critical indicators of marine ecosystem health, yet little is known about their population structure and ecological roles in tropical oceanic regions. This doctoral thesis investigates the population genetics, connectivity, and trophic ecology of two cetacean species, blue whales (Balaenoptera musculus) and common bottlenose dolphins (Tursiops truncatus), within the Galapagos Marine Reserve and the broader Ecuadorian Whale Sanctuary. Using mitochondrial DNA, genome-wide SNPs, and stable isotope analyses (δ13C and δ1⁵N), this research explores how environmental variability, particularly El Nino Southern Oscillation (ENSO) events, influences foraging strategies and genetic structure.
Blue whale samples revealed high haplotype diversity (Hd = 0.919), including three novel haplotypes, indicating connectivity between Eastern North and Southeast Pacific populations. Haplotype richness increased during El Nino events, suggesting shifts in migratory routes driven by oceanographic change. Isotopic analyses showed whales exhibited broader foraging niches during La Nina years and narrower, more specialized diets during El Nino, highlighting their flexible responses to fluctuating productivity.
In bottlenose dolphins, stable isotope data from 94 individuals revealed spatial and sexbased trophic variation across four Galapagos regions. Central-region dolphins showed enriched isotope values consistent with nearshore, high-trophic feeding, while outer-region dolphins exhibited more depleted values, reflecting offshore diets. Genetic analyses indicated high connectivity and limited population structure, except in the Far North, which showed localized differentiation.
Overall, this thesis demonstrates that Galapagos cetaceans exhibit ecological plasticity and wide-ranging genetic connectivity, shaped by environmental variability. These findings underscore the value of combining molecular and ecological tools to inform adaptive conservation strategies in the Eastern Tropical Pacific.
Details
- Title
- Population Genetics and Trophic Ecology of Two Cetacean Species in the Ecuadorian Whale Sanctuary, the Galapagos Archipelago
- Authors
- Daniela Estefania Alarcon Ruales - University of the Sunshine Coast, Queensland, School of Science, Technology and Engineering
- Contributors
- Kathy A Townsend (Principal Supervisor) - University of the Sunshine Coast, Queensland, School of Science, Technology and EngineeringDominique A Potvin (Co-Supervisor) - University of the Sunshine Coast, Queensland, Centre for BioinnovationBonnie Holmes (Co-Supervisor) - University of the Sunshine Coast, Queensland, School of Science, Technology and Engineering
- Awarding institution
- University of the Sunshine Coast, Queensland
- Degree awarded
- Doctor of Philosophy
- DOI
- 10.25907/01016
- Organisation Unit
- School of Science, Technology and Engineering
- Language
- English
- Record Identifier
- 991211281402621
- Output Type
- Dissertation
Metrics
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