Document Type
Dissertation
Degree
Doctor of Philosophy (PhD)
Major/Program
Biology
First Advisor's Name
Yannis Papastamatiou
First Advisor's Committee Title
Committee Chair
Second Advisor's Name
Michael Heithaus
Second Advisor's Committee Title
Committee Member
Third Advisor's Name
Jennifer Rehage
Third Advisor's Committee Title
Committee Member
Fourth Advisor's Name
Joel Trexler
Fourth Advisor's Committee Title
Committee Member
Fifth Advisor's Name
Elizabeth Babcock
Fifth Advisor's Committee Title
Committee Member
Keywords
abundance, accelerometry, acoustic telemetry, baited remote underwater video stations, behaviour, Caribbean, coral reefs, ecology, sharks, stingrays
Date of Defense
3-29-2023
Abstract
Shark declines may cause trophic cascades, which is partially dependent on how sharks influence prey abundance and behaviour. Rays are mesopredators that play a unique role in ecosystems as bioturbators. My dissertation investigates whether sharks induce changes in ray sightings, behaviour, and habitat use across multiple spatial and temporal scales. First, I reviewed the ray ecology literature and found limited evidence for risk-induced ray trait responses (Chapter 1). Next, using a baited remote underwater video station (BRUVS) survey, I found that southern stingray (Hypanus americanus) sightings were negatively associated with shark abundance throughout the tropical Western Atlantic Ocean (Chapter 2). Other important predictors of southern stingray sightings in the region included habitat complexity, geomorphology, and bottom fishing gear. At a smaller spatial scale inside the Glover’s Reef Marine Reserve in Belize, a BRUVS survey revealed southern stingray sightings and behaviour remained stable between 2009 – 2019 despite a concurrent decline in the relative abundance of Caribbean reef sharks (Carcharhinus perezi) (Chapter 3). Habitat complexity explained southern stingray sightings and behaviour on BRUVS, which may be due to their preference for soft bottom habitats and/or because we are less likely to detect stingrays on BRUVS in areas with high reef relief. Passive acoustic telemetry showed Caribbean reef and lemon (Negaprion brevirostris) sharks use shallow lagoon habitat, which was also the preferred habitat of southern stingrays, suggesting it is unlikely a refuge from predators. Finally, using accelerometry and hidden Markov models, I found that southern stingray activity is crepuscular and nocturnal, with high individual variation (Chapter 4). Southern stingrays were highly active in shallow water (m), which is likely associated with prey activity and availability. My findings emphasize the context dependent nature of predation risk effects and the need to take a multimethod approach to understand ray behaviour and habitat use.
Identifier
FIDC011036
ORCID
https://orcid.org/0000-0002-4354-2948
Previously Published In
Flowers KI, Heithaus MR, Papastamatiou YP (2021) Buried in the sand: Uncovering the ecological roles and importance of rays. Fish and Fisheries 22: 105 – 127.
Recommended Citation
Flowers, Kathryn I., "Stingray Behaviour and Habitat Use in Response to Sharks in Caribbean Coral Reef Ecosystems" (2023). FIU Electronic Theses and Dissertations. 5286.
https://digitalcommons.fiu.edu/etd/5286
Included in
Aquaculture and Fisheries Commons, Behavior and Ethology Commons, Biology Commons, Zoology Commons
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