Sentinels of the Sea: Marine Mammal Behavioral Responses to Environmental Change

This research investigates how two potential sentinel species (the Galápagos Sea Lion (Zalophus wollebaeki) and the Guiana Dolphin (Sotalia guianensis)) respond to environmental factors, at both the large-scale and fine-scale levels. Sentinel species, defined as organisms able to respond to ecosystem variability and/or change in a timely and measurable way to nowcast or forecast otherwise unobserved environmental changes, can help mitigate or even avoid changes deleterious to both wildlife and human communities. Using two long-term datasets and a suite of respective social metrics and environmental factors, I analyzed potential external influences on these two species’ behavioral ecology. My overall findings suggest that apex marine mammals respond differently to their surroundings at large-scale vs. fine-scale, and highlight the importance of including a range of environmental factors that include anthropogenic effects. Galápagos Sea Lions specifically respond to thermoregulation-linked factors, such as substrate temperature, and anthropogenic factors such as human presence and activity type. Guiana Dolphin social metrics are significantly related with traits linked to environmental water quality, water transparency. I expand on the sentinel implications of these results and introduce sample methodology and results for sentinel species based on the Guiana Dolphin case study.