Fish fecal pellets are a source of minerals for inshore reef communities

Abstract

Fecal pellets of temperate and tropical reef fishes of the genus Chrornis contained high concentrations of minerals, many of which are considered 'essential' for organismic growth. The concentrations of most elements were substantially higher in the feces than in undigested food recovered from the stomach. Large numbers of feces-associated bacteria, apparently derived from the gut microbial population, may have contributed to the high phosphorus levels in fresh feces. Phos-phorus flux to inshore reefs via defecation of fecal pellets by the blacksmith C. punctipinnus in nocturnal shelters was comparable to estimates of phosphorus transport through surface waters by sinking zooplankton feces. Resistance of fecal pellets to degradation during long-term in d t u incuba-tion in nocturnal shelters suggests that bacteria do not play a significant role in controlling accumula-tion of fish feces on the reef.