DOI: 10.5061/dryad.5mkkwh76r
title: Coprophagy in Caribbean parrotfishes

description: 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.
 Because of the top-down effects associated with their benthic foraging,
 this has been a major focus of parrotfish research. Another aspect of
 parrotfish foraging and trophic ecology that has received very little
 attention is coprophagy, the consumption of fecal matter. 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. Their feces are readily consumed by a variety
 of fishes, including parrotfishes. Although parrotfish coprophagy has been
 observed in prior studies, its frequency has not yet been quantified. In
 this study, we observed foraging in five parrotfishes on the fringing
 reefs of Bonaire, Netherlands: Scarus iseri, Scarus taeniopterus, Scarus
 vetula, Sparisoma aurofrenatum, and Sparisoma viride. For three of these
 species, we observed individuals of both ontogenetic phases (terminal and
 initial phase) to investigate ontogenetic differences in foraging. We
 found that coprophagy was common in four of these species
 (Sc. iseri, Sc. taeniopterus, Sc. vetula,
 and Sp. aurofrenatum), occurring in 46-90%
 of individuals (Sc. vetula and Sc. taeniopterus,
 respectively). Though we did not identify the origin of every
 fecal pellet consumed, we directly observed focal fishes targeting fecal
 pellets produced by planktivorous Chromis spp. that were often seen
 schooling above the reef during this feeding behavior. Additionally, most
 of the fecal pellets consumed by the parrotfishes were similar in
 appearance (i.e., relative size, shape, coloration, and consistency) to
 the feces produced by Chromis spp., predominantly Chromis multilineata,
 suggesting this common origin. However, bites on fecal matter were a
 relatively small proportion of the total bites taken by these
 species (&lt; 5%). In contrast, a majority of bites
 taken by these species were taken on substrates classified as
 eplithic algal matrix (EAM) or crustose coralline algae (68.5-90.6% of
 total bites across all five species). Despite being an infrequent
 target of parrotfish foraging, we estimated that daily fecal C consumption
 is equivalent to approximately 27% of the daily algal C intake by
 parrotfishes targeting the major benthic foraging targets of parrotfishes
 (large turfs, small turfs on endolithic algae or crustose coralline algae,
 and crustose coralline algae) in Bonaire. The feces of
 plantivorous reef fishes like Chromis spp. are also
 likely a valuable source of nutrients to reef fishes, because the fecese
 of Chromis spp. has higher protein and lipid content and lower
 C:N and C:P than many benthic marine algae and cyanobacteria, including
 from the tropics. The absence of coprophagy in Sp. viride and
 reduced rates of coprophagy in Sc. vetula relative to the other
 coprophagic species could be the result of increased access to
 protein-rich endolithic components of the benthos. Access to endolithic
 components of the benthos increases with body size and the
 ability to excavate benthic substrate while foraging. Sparisoma viride is
 an important excavating parrotfish on Caribbean coral reefs, and
 Sc. vetula is generally larger than the other coprophagic species in our
 study. Future work should attempt to further quantify the
 contribution of fecal matter to the nutrition of parrotfishes relative to
 benthic foraging targets in order to provide a more complete understanding
 of parrotfish nutritional ecology and to elucidate the importance of
 coprophagy in nutrient recycling and retention on coral reefs. 
description: Data were collected across 5 fringing reef sites in Bonaire, NL:
 Angel City (AC; 12.10305º, -68.28852º), Aquarius (AQ; 12.09824º,
 -68.28624º), Bachelor’s Beach (BB; 12.12605º, -68.28819º), Invisibles (IV;
 12.07805º, -68.28175º), and The Lake (TL; 12.10618º, -68.29079º) during
 May-July 2019. We conducted visual censuses of initial
 and terminal phase parrotfish (forklength &gt; 6 cm) along eight
 100-m<sup>2</sup> (25-m x 4-m) band transects at each site to
 quantify density and biomass of parrotfishes (parrotfishes.csv). We also
 quantified the cover of benthic functional groups using photoquadrats
 (n=10) placed at 1-m intervals along 10-m transects (n=4 at each site
 with 1 additional transect with 3 photoquadrats at AQ) running
 perpendicular to the reef slope at approximately 10-m depth at each site
 (benthic-cover.csv). In addition to quantifying the total cover of coral
 at these 5 sites, we also identified corals to the species level to
 explore differences in coral community composition across sites. Total
 coral cover was therefore broken down by species as well.
 Finally, we conducted foraging observations of 162 unique
 individuals of the 5 most common parrotfishes across our 5 fringing reef
 sites: <em>Scarus iseri</em>, <em>Scarus
 taeniopterus</em>, <em>Scarus vetula</em>,
 <em>Sparisoma aurofrenatum</em>, and <em>Sparisoma
 viride</em>. For 3 species (<em>Scarus
 taeniopterus</em>, <em>Scarus vetula</em>, and
 <em>Sparisoma viride</em>), we conducted observations of both
 ontogenetic phases (initial and terminal phase) to investigate ontogenetic
 differences in foraging. During these foraging observations we video
 recorded parrotfish behavior and later scored videos, recording all bites
 taken, the target of those bites (benthic functional groups and bites on
 feces in the water column), and when coral was bitten, the species of
 coral targeted was identified (bites.csv). The standard length (cm) of
 every fish, the total duration of each observation (mins), the time during
 each video recorded observation that the fish was not visible (mins), and
 the final follow time (total time - lost time; mins) are also reported for
 each fish (follow-data.csv). The final follow time (Final.Time) is what we
 used for analyses of foraging rates. All fish were followed between
 ~1000-1600 hrs local time in Bonaire (AST, UTC/GMT -4).
description: <strong>parrotfishes.csv metadata:</strong>
 Site - Fringing Reef Sites: AC, Angel City; AQ, Aquarius; BB,
 Bachelor's Beach; IV, Invisibles; TL, The Lake.
 NamePhase - Common name and ontogenetic phase (initial and
 terminal phase; IP and TP, respectively) of the parrotfishes
 observed. CommonName - Common names of parrotfishes
 observed. ScientificName - Scientific names of
 parrotfishes observed. Transect - Transect number
 (e.g., T1 is transect 1). Bin - Parrotfishes were
 binned by forklength (cm) and these values indicate size class that fishes
 were binned into (e.g., B6.10 is for fishes 6-10cm forklength).
 AvgLength - The average forklength (cm) for each bin.
 Density - Counts of parrotfishes per
 100-m<sup>2</sup> band transect (25-m x 4-m) for a given
 species/phase/bin. Biomass - Biomass (g 100
 m<sup>-</sup><sup>2</sup>) of each row calculated
 using AvgLength, Density, and species-specific published length-weight
 ratios (Bohnsack and Harper 1988).  
 <strong>benthic-cover.csv
 metadata:</strong> Site - Fringing Reef Sites:
 AC, Angel City; AQ, Aquarius; BB, Bachelor's Beach; IV, Invisibles;
 TL, The Lake. Transect - Transect number.
 Quadrat - Photoquadrat number. Columns 4-14
 (Epilithic Algal Matrix - Unknown) - These columns contain the percent
 cover for each benthic functional group (Epilithic Algal Matrix, Coral,
 Gorgonian, Sponge, Macroalgae, Other Live, Benthic Cyanobacterial Mat,
 Articulated Coralline Algae, Crustose Coralline Algae, Sediment,
 Unknown). Columns 15-32 (Orbicella.annularis..OA. -
 Porites.divaricata..PD.) - Contain the percent cover of different coral
 species, labeled as "Genus.species..Abbreviation." The row
 totals for these columns sum to the total coral cover.
   <strong>bites.csv
 metadata:</strong> Season - Season in which the
 observations were made (Summer, Northern Hemisphere).
 Site - Fringing Reef Sites: AC, Angel City; AQ, Aquarius; BB,
 Bachelor's Beach; IV, Invisibles; TL, The Lake.
 Date - Date of observation in M/D/YYYY format.
 Species - Scientific name of parrotfish observed
 (<em>Scarus iseri</em>, <em>Scarus
 taeniopterus</em>, <em>Scarus vetula</em>,
 <em>Sparisoma aurofrenatum</em>, and <em>Sparisoma
 viride</em>). Phase - Ontogenetic phase of the
 parrotfish observed: initial phase (IP) or terminal phase (TP).
 Num - Fish Number. Rep - Replicate; always
 1. Behavior - Always Bite. Substrate
 - Substrate bitten, same functional groups as recorded for benthic
 cover. Coral - If coral was bitten, the species of
 coral is given here (e.g., Orbicella faveolata). If no coral was bitten,
 the value is None.  
 <strong>follow-data.csv metadata</strong>
 Season - Season in which the observations were made (Summer,
 Northern Hemisphere). Site - Fringing Reef Sites: AC,
 Angel City; AQ, Aquarius; BB, Bachelor's Beach; IV, Invisibles; TL,
 The Lake. Date - Date of observation in M/D/YYYY
 format. Species - Scientific name of parrotfish
 observed (<em>Scarus iseri</em>, <em>Scarus
 taeniopterus</em>, <em>Scarus vetula</em>,
 <em>Sparisoma aurofrenatum</em>, and <em>Sparisoma
 viride</em>). Phase - Ontogenetic phase of the
 parrotfish observed: initial phase (IP) or terminal phase (TP).
 Num - Fish Number. Rep - Replicate; always
 1. Total.Time - Total time (mins) of video-recorded
 foraging observation (i.e., from time camera was pointed at fish to when
 it was taken off the fish to end the observation).
 Lost.Time - Time (mins) during video-recorded foraging
 observation during which the focal fish was not clearly visible in the
 video (e.g., under a coral head for more than a second or two). 
 Follow.Time - Calculated as the Total.Time - Lost.Time, this is
 the value we used to quantify rates of foraging and as an offset in
 statistical models because it is the true "observation duration"
 (mins).  SL - The standard length (cm) of each focal
 fish, estimated by the observer <em>in situ</em>.