Crown-of-Thorns Starfish Larvae Can Feed on Organic Matter Released from Corals

Ryota Nakajima,Nobuyuki Nakatomi,Michael Fox,Haruko Kurihara,Jennifer Smith,Ken Okaji

doi:10.3390/d8040018

Abstract

Previous studies have suggested that Crown-of-Thorns starfish (COTS) larvae may be able to survive in the absence of abundant phytoplankton resources suggesting that they may be able to utilize alternative food sources. Here, we tested the hypothesis that COTS larvae are able to feed on coral-derived organic matter using labeled stable isotope tracers (13C and 15N). Our results show that coral-derived organic matter (coral mucus and associated microorganisms) can be assimilated by COTS larvae and may be an important alternative or additional food resource for COTS larvae through periods of low phytoplankton biomass. This additional food resource could potentially facilitate COTS outbreaks by reducing resource limitation.

Highlights

Outbreaks of Crown-of-Thorns starfish (COTS), Acanthaster spp., can have devastating effects on coral reefs throughout the Pacific and Indian Oceans [1,2]
We refer to the individuals from the Pacific Ocean clade COTS used in this study as Acanthaster cf. solaris [44,45]
(1.68h–1.98h) are similar to values reported in other studies ([46] ca. 2.00h), we consider that the coral mucus in our experiment was successfully labeled

Summary

Introduction

Outbreaks of Crown-of-Thorns starfish (COTS), Acanthaster spp., can have devastating effects on coral reefs throughout the Pacific and Indian Oceans [1,2]. These coral mucus aggregates are considered to be one of the major contributors to the origin of particulate organic matter (POM) in reef waters [36,38] These mucus aggregates have been reported as an important food source for various reef animals, such as fish, zooplankton, and several benthic taxa, such as coral crabs and brittle stars [39]. Be an important food source for COTS larvae that develop on or near coral reefs during periods of low phytoplankton biomass. If COTS larvae feed on organic matter released by corals, this would represent an additional food source not previously considered This additional food resource may enhance the survival of COTS larvae and subsequent recruitment of adults in areas that are naturally low in phytoplankton abundance and/or during times of reduced phytoplankton biomass

Collection of COTS Larvae

Collection of Coral Mucus

Feeding Experiments

Analysis

Results and Discussion