About This Project

We study an abundant 'herbivorous' fish on Pacific coral reefs: the striated surgeonfish, Ctenochaetus striatus. Understanding its role in the reef ecosystem, and what it eats, is critical given its decline on some reefs. This charismatic fish helps keep the reef 'clean' which facilitates coral settlement, but we don't know exactly how. We aim to combine genetic barcoding of feces with behavioral studies to provide some answers about its diet.

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What is the context of this research?

This is part of a larger question about the importance of coral reef herbivorous fish to reef health. Herbivory is a broad category and we are interested in the roles of abundant herbivorous fish that may be eating specific organisms and therefore playing a targeted role in the ecosystem helping corals thrive. Fish that clear, clean, and otherwise alter substrates on coral reefs through their feeding may be making space available for coral larvae to settle and grow. Understanding diets of fish liker C. striatus can help with management and conservation of coral reefs, and can help communities that steward these systems make informed decisions about fishing. We plan to use novel technologies (DNA metabarcoding) to determine diet diversity.

What is the significance of this project?

Our world's coral reefs are suffering today under multiple stressors. But they CAN be resilient, and we CAN mitigate their stressto some degree. While we may not be able to control climate change immediately, we can limit some of the other stressors, and encourage ecosystem level connections that can help. Fish are a critical component of that. These busy members of reefs have functional roles - their activities have an impact on the ecosystem. Understanding that impact can help us 'use' them as tools for reef stability and even recovery. If we understand the specific role of an abundant fish like C. striatus (striated surgeonfish), we can co-develop management strategies that promote its positive role.

What are the goals of the project?

Our main hypothesis/question: does C. striatus show selectivity in diet from specific substrates, and what does it prefer to eat? Observations and samples were collected in Moorea, FP.

We will use metabarcoding to get a list of organisms from inside the striated surgeonfish, as well as on substrates it feeds on. These will be compared to determine its feeding preferences. We will barcode samples 1. In the feces, which we collected while watching them underwater until they deposited a sample. 2. In their stomachs - we collected these from fish that we bought from fishermen. 3. From the substrates on which they feed (we sampled these from the reef). 4. From ambient surrounding seawater.