Coprophagy by Herbivorous Caribbean Fishes

Parrotfishes and surgeonfishes are important herbivores on Caribbean reefs, but did you know that they also consume fish feces (a behavior known as coprophagy)? Master’s student Hannah Rempel discovered that they some species regularly consume the feces of the planktivore Brown chromis while conducting research in Bonaire last year. To better understand this novel behavior, Hannah and undergraduate Abby Siebert are are evaluating species-specific patterns of coprophagy by herbivorous fishes on Caribbean reefs.

A Princess parrotfish (Scarus taeniopterus) and Blue tang (Acanthurus coeruleus)
​compete for a Brown chromis (Chromis multilineata) fecal pellet, circled in red.​
Image copyright Hannah Rempel 2019, not for use without permission.

Why do they do this? Maybe for a little 'Vitamin Sea'. We theorize that the feces of planktivores may provide an important nutritional supplement to their algae-dominated diet. Last summer, Abby was awarded a Cal Poly FROST Undergraduate Research Program fellowship to study the nutritional quality of fecal samples with Hannah. She is continuing this research for her senior project, evaluating the carbohydrate, lipid, and protein and trace mineral content of Brown chromis feces, which will help us better understand the nutritional drivers of this behavior.

Want to learn more about this work? Abby gave a virtual talk at The California Central Coast Chapter of The Wildlife Society's annual symposium earlier in October and will be presenting a poster at The Western Society of Naturalists in November.  Stay tuned for more updates, as moving forward Abby will continue presenting this research at scientific conferences and we anticipate a research paper led by Hannah and Abby will be forthcoming next year. ​