NSF Award
2422550
Large marine predators such as cetaceans (whales, dolphins, and porpoises) can play important roles in marine ecosystems both as predators and prey. Small cetaceans such as dolphins can be locally abundant and due to their fast metabolism, they rely on predictable sources of food. They are also prey for a range of predators such as sharks, particularly in tropical ecosystems, and are vulnerable to habitat degradation and disturbances from vessel traffic. However, the factors behind how marine predators such as dolphins use their habitat, such as where to find food, safe places to rest, and to socialize, are not well understood. This information will be useful for predicting how they may respond to climate change or to human impacts, such as pollution, overfishing, or boating activity. The goal of this project is to assess how environmental factors affect the behavior and habitat use of marine predators, using coastal dolphins as model organisms. The factors measured will be food availability, predation risk, and boating activity relative to observed dolphin behaviors. The results from this project will help us to better understand and predict how vulnerable marine predators respond to long-term habitat degradation in coastal marine ecosystems.<br/><br/>Little is known about the impacts of urbanization on coastal marine mammals, both directly and indirectly, through changes in prey dynamics and predation risk, or anthropogenic disturbances that can be perceived similarly as predation risk. This project will investigate how variation in anthropogenic and natural drivers are influencing foraging and habitat use decisions of a model upper trophic level predator (bottlenose dolphins, Tursiops truncatus) in a highly urbanized coastal environment. The study will use behavioral ecological theory to test predictions about how dolphins should respond to spatiotemporal variation in prey abundance and predation risk that are likely being modified by human activities in the study area. The study will also investigate whether human disturbance (i.e. boat traffic) results in changes in dolphin behavior that are consistent with the risk-disturbance hypothesis. The methods used in this project will be to: 1) conduct an assessment of prey landscapes along a gradient of human pressure using novel eDNA sampling techniques and baited remote underwater videos (BRUV’s), 2) use active acoustics and video imaging to map benthic habitats, and 3) integrate data on dolphin behavior, boat traffic, prey, and predation risk to test a priori hypotheses of dolphin habitat use and behavior. This interdisciplinary approach provides a comprehensive method of examining habitat use and behavior of elusive marine predators in highly impacted systems. Anticipated results of this study will not only advance the capacity to predict changes in movement, habitat use, and behavior of coastal marine predators in other similar urbanized waterways, but it will also allow us to make future predictions on the viability of populations or population segments exposed to different levels of human impacts and provide important information for stock assessment and management.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
