A photo time series showing: (a) a Queen parrotfish consuming a Brown chromis fecal pellet and (b) a Princess parrotfish and Blue tang surgeonfish competing for a fecal pellet.
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Coral reefs are typically low in vital nutrients, but are hotspots of biodiversity. Recycling of nutrients is key to supporting this diverse array of marine life. Feces consumption may be an important, yet understudied way that nutrients are recycled on reefs– nature's "vitamin sea".
We found that Caribbean reef fishes regularly consume the feces of Brown Chromis, a plankton-eating fish. Of >100 Brown Chromis feces we tracked, 84% were consumed before they reached the reef benthos and >90% of consumed fecal pellets were eaten by parrotfishes and surgeonfishes alone! Why might they be targeting planktivore feces? Thes fecal pellets were rich in important macronutrients like protein and micronutrients like phosphorous compared to most other major food sources of these fish. |
A time series of photos showing parrotfish predation scars on Orbicella annularis corals, with (a) rapid, full healing of a small scar and (b) minimal healing of a large scar that were reflective of patterns we observed.
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Parrotfishes primarily feed on algae and cyanobacteria, but some species also occasionally feed on live coral. Caribbean parrotfishes commonly bite Orbicella annularis corals, an important framework-building coral and endangered species. How often do these scars heal and what is the long-term coral tissue loss from parrotfish predation scars?
To address this question we tracked the fate of >450 recent scars on O. annularis corals and used these data to developed a predictive model of coral healing dynamics. We applied the model to surveys of fresh scar standing stock to predict long-term coral tissue loss. We found that most parrotfish predation scars were small and predicted to heal (image series a), while infrequent but large bites from repetitive predation over a focused area were predicted to cause the vast majority of coral tissue loss (image series b). |
Parrotfishes play key roles in facilitating coral resilience grazing algae and cyanobacteria that can overgrow corals. But, some parrotfishes also occasionally bite coral, which may have negative impacts on coral growth and survival. How does the intensity of parrotfish coral predation vary in response to coral cover and parrotfish abundance?
To address this question, collaborators and I compared patterns of parrotfish coral predation across four regions of the Greater Caribbean spanning broad gradients in parrotfish abundance and coral cover. Stay tuned for forthcoming findings! |
Large-scale coral bleaching events are caused by rising ocean temperatures associated with climate change. Monitoring the intensity of bleaching over time can help inform coral species and site-specific reef conservation strategies.
While working as an Assistant Biologist for the STINAPA Bonaire National Parks Foundation, Hannah and colleagues began annual monitoring of bleaching on Bonaire. STINAPA Biologist Caren Eckrich led a public report on findings from monitoring patterns of coral bleaching from 2016-2020 across depths and among coral species. |