Preprint Article Version 1 NOT YET PEER-REVIEWED

Larval Survivorship and Settlement of Crown-of-Thorns Starfish (Acanthaster cf. solaris) at Varying Chlorophyll Concentrations

  1. ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville QLD 4811, Australia
  2. National Marine Science Centre, Southern Cross University, Coffs Harbour NSW 2450, Australia
  3. Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
Version 1 : Received: 14 November 2016 / Approved: 14 November 2016 / Online: 14 November 2016 (07:49:50 CET)

How to cite: Pratchett, M.; Dworjanyn, S.; Mos, B.; Caballes, C.; Thompson, C.; Blowes, S. Larval Survivorship and Settlement of Crown-of-Thorns Starfish (Acanthaster cf. solaris) at Varying Chlorophyll Concentrations. Preprints 2016, 2016110074 (doi: 10.20944/preprints201611.0074.v1). Pratchett, M.; Dworjanyn, S.; Mos, B.; Caballes, C.; Thompson, C.; Blowes, S. Larval Survivorship and Settlement of Crown-of-Thorns Starfish (Acanthaster cf. solaris) at Varying Chlorophyll Concentrations. Preprints 2016, 2016110074 (doi: 10.20944/preprints201611.0074.v1).

Abstract

The dispersal potential of crown-of-thorns starfish (CoTS) larvae is important in understanding both the initiation and spread of population outbreaks, and is fundamentally dependent upon how long larvae can persist while still retaining the capacity to settle. This study quantified variation in larval survivorship and settlement rates for CoTS maintained at three different chlorophyll concentrations (0.1, 1.0 or 10.0 µg.L-1), achieved by varying densities of single-celled flagellate phytoplankton, Proteomonas sulcata. Based on the larval starvation hypothesis we expected that low to moderate algal concentrations would significantly constrain both survival and settlement. CoTS larvae were successfully maintained for up to 50 days post-fertilization, but larval survival differed significantly between treatments. Survival was greatest at intermediate (1.0 µg.L-1) chlorophyll concentrations, and lowest at highest (10.0 µg.L-1) chlorophyll concentrations. Rates of settlement were also highest at intermediate (1.0 µg.L-1) chlorophyll concentrations and peaked at 22 days post-fertilization. Peak settlement was delayed at low chlorophyll concentrations, probably reflective of delayed development, but there was no evidence of accelerated development at high chlorophyll concentrations. CoTS larvae were capable of settling 17-43 days post-fertilization, but under optimum conditions with intermediate chlorophyll concentrations, peak settlement occurred at 22 days post-fertilization. Moderate increases in nutrient concentrations and algal densities may increase the number of CoTS that effectively settle, but are unlikely to influence dispersal dynamics.

Subject Areas

Acanthaster; coral reefs; food limitation; larval competency; planktonic larval duration (PLD)

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