Bulletin of the Ecological society of america

Parrotfishes can often be observed consuming fish feces on coral reefs. Our recent study highlights the nutritional value of these feces to parrotfishes. Four of the five most common species at our study sites (Bonaire, Caribbean Netherlands) consumed feces, mostly from Chromis multilineata. Despite being infrequent (<4% total bites), we estimate that coprophagy may contribute ~27% of the carbon obtained by parrotfishes while foraging on preferred benthic substrates. Chromis feces also have higher protein and lipid contents and lower C:N:P ratios than other foraging targets (algae and cyanobacteria). Coprophagy is, therefore, likely an important and understudied component of parrotfish nutrition.

Parrotfishes are widely considered to be important grazers on coral reefs that remove autotrophic biomass from the reef substrate and create bare space that is conducive to larval coral settlement and recruitment (Bonaldo et al., 2014). Another aspect of parrotfish foraging and trophic ecology that has received very little attention is coprophagy. Coprophagy, the consumption of fecal matter, occurs in many animal taxa and may be an important means of subsidizing nutritional requirements (i.e., micro- and macronutrients) not met through foraging on preferred resources alone (Bailey & Robertson, 1982; Johannes & Satomi, 1966; Negro et al., 2002; Robertson, 1982).

The feces of planktivorous fishes, including Chromis spp., have been identified as important sources of nutrients and trace elements to tropical and temperate reef ecosystems (Geesey et al., 1984; Hamner et al., 1988; Pinnegar & Polunin, 2006). Their feces are readily consumed by a variety of fishes, including parrotfishes (Pinnegar & Polunin, 2006; Robertson, 1982). Although parrotfish coprophagy has been observed in prior studies (Motta & Overholtzer, 1999; Robertson, 1982), its frequency has not yet been quantified.

In May–July 2019, we conducted video-recorded foraging observations of 162 parrotfishes across five fringing coral reef sites in Bonaire, NL to quantify benthic foraging targets for the five most common species on those reefs

Parrotfishes can often be observed consuming fish feces on coral reefs. Our recent study highlights the nutritional value of these feces to parrotfishes.  Four of the five most common speciesa t our study sites (Bonaire, Caribbean Netherlands) consumed feces, mostly from Chromis multilineata. Despite being infrequent (<4% total bites), we estimate that coprophagy may contribute ~27% of the carbon obtained by parrotifhses while foraging on preferred benthic substrates. Chromis feces also have higher protein and lipid conetents and lower C:N:P ratios than other foraging targets (algae and cyanobaceteria). Coprophagy is, thereofre, likely an important nad understudied component of parrotfish nutrition.

Read more at: https://www.jstor.org/stable/48657233

https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3657