Impacts of Parrotfishes on Caribbean Coral Reefs
Parrotfishes are major herbivores on coral reefs that have an important functional role grazing algae that can otherwise overgrow or outcompete corals. A primary management across many regions of the Caribbean is to promote coral reef resilience by maintaining abundant populations of parrotfishes and other herbivores to help regulate algae growth on reefs. Islands like Bonaire and Bermuda have banned the harvest of parrotfishes altogether, yet parrotfish fishing pressure is high on islands like Jamaica and St. Croix, US Virgin Islands.
While parrotfishes primarily graze algae, some species occasionally eat live coral in addition to algae. While they graze coral infrequently, this predation can cause partial mortality of coral recruits and established colonies, and may reduce coral reproductive output and growth. The challenge is that we currently have a limited understanding of factors that influence this behavior and the long-term impacts that is had on coral colonies.
To assess the net impacts of parrotfishes on coral reefs across the Greater Caribbean, our lab and our collaborators are studying the positive impacts of parrotfish herbivory and the negative impacts of parrotfish corallivory across the Florida Keys, St. Croix and Bonaire.
While parrotfishes primarily graze algae, some species occasionally eat live coral in addition to algae. While they graze coral infrequently, this predation can cause partial mortality of coral recruits and established colonies, and may reduce coral reproductive output and growth. The challenge is that we currently have a limited understanding of factors that influence this behavior and the long-term impacts that is had on coral colonies.
To assess the net impacts of parrotfishes on coral reefs across the Greater Caribbean, our lab and our collaborators are studying the positive impacts of parrotfish herbivory and the negative impacts of parrotfish corallivory across the Florida Keys, St. Croix and Bonaire.
Ongoing Research
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The goals of our ongoing research are to better understand the drivers and impacts of parrotfish corallivory. Our specific research aims to: (1) determine what factors influence the healing of an endangered, frequently targeted coral species from parrotfish grazing scars, (2) use these data to develop a predictive model of coral healing from parrotfish bite scars based on surveys of distribution of scars present on corals at a point in time, and (3) compare how the intensity of parrotfish predation on corals varies between three regions of the Greater Caribbean with large differences in coral cover, parrotfish biomass, and other metrics of coral reef community composition to better understand ecological drivers of corallivory.
To learn more about this work, read a recent publication on this research (Rempel et al. 2020) and watch our Global Coral Reef Week presentation on this research below. Data from this and other studies are publically available through NOAA's National Centers for Environmental Information (see links at the bottom of this page). Our previous research on parrotfish grazing behavior has helped address questions such as: (1) How much species-to-species variation is there is parrotfish feeding preferences on algae and other food sources such as sponges and coral? (2) How their grazing behavior vary depending on local community composition of reefs? To learn more about out findings, check out the follow publications on foraging behavior of Caribbean parrotfishes by our lab and our collaborators in the UC Santa Barbara Burkepile Lab: Adam et al. 2015A, Adam et al. 2015B, Adam et al. 2018, Ruttenberg et al. 2019, Burkepile et al. 2019 |
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Data Availability
Data from these studies are publically available through NOAA's National Centers for Environmental Information:
- Patterns of parrotfish predation on Orbicella annularis and coral tissue regeneration from bite scars on the Caribbean islands of St. Croix and Bonaire from 2018-07-02 to 2019-08-24 (NCEI Accession 0213589)
- Abundance and biomass of parrotfishes (Labridae, Scarinae) in St.Croix, U.S. Virgin Islands 2015 to 2016 (NCEI Accession 0172377)
- Behavior of parrotfishes (Labridae, Scarinae) in St. Croix from 2015-07-06 to 2015-07-26 (NCEI Accession 0157087)
- Parrotfish census and foraging parameters in the Florida Keys National Marine Sanctuary from 2013-05-01 to 2013-07-31 (NCEI Accession 0185785)
- Abundance and behavior of parrotfishes (Labridae, Scarinae) in the upper Florida Keys from 2013-06-19 to 2013-07-30 (NCEI Accession 0127525)