Joint estimation of crown of thorns (Acanthaster planci) densities on the Great Barrier Reef

M Aaron MacNeil; Camille Mellin; Morgan S Pratchett; Jessica Hoey; Kenneth R N Anthony; Alistair J Cheal; Ian Miller; Hugh Sweatman; Zara L Cowan; Sascha Taylor; Steven Moon; Chris J Fonnesbeck

doi:10.7717/peerj.2310

Joint estimation of crown of thorns (Acanthaster planci) densities on the Great Barrier Reef

PeerJ. 2016 Aug 31:4:e2310. doi: 10.7717/peerj.2310. eCollection 2016.

Authors

Affiliations

¹ Australian Institute of Marine Science, Townsville, Queensland, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia; Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada.
² Australian Institute of Marine Science, Townsville, Queensland, Australia; The Environment Institute and School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.
³ ARC Centre of Excellence for Coral Reef Studies, James Cook University , Townsville , Queensland , Australia.
⁴ Great Barrier Reef Marine Park Authority , Townsville , Queensland , Australia.
⁵ Australian Institute of Marine Science , Townsville , Queensland , Australia.
⁶ Queensland Parks and Wildlife Service (Marine Parks), Queensland Deptartment of National Parks, Sport and Racing , Brisbane , Queensland , Australia.
⁷ Association of Marine Park Tourism Operators , Cairns , Australia.
⁸ Department of Biostatistics, Vanderbilt University Medical Center , Nashville , TN , United States of America.

Abstract

Crown-of-thorns starfish (CoTS; Acanthaster spp.) are an outbreaking pest among many Indo-Pacific coral reefs that cause substantial ecological and economic damage. Despite ongoing CoTS research, there remain critical gaps in observing CoTS populations and accurately estimating their numbers, greatly limiting understanding of the causes and sources of CoTS outbreaks. Here we address two of these gaps by (1) estimating the detectability of adult CoTS on typical underwater visual count (UVC) surveys using covariates and (2) inter-calibrating multiple data sources to estimate CoTS densities within the Cairns sector of the Great Barrier Reef (GBR). We find that, on average, CoTS detectability is high at 0.82 [0.77, 0.87] (median highest posterior density (HPD) and [95% uncertainty intervals]), with CoTS disc width having the greatest influence on detection. Integrating this information with coincident surveys from alternative sampling programs, we estimate CoTS densities in the Cairns sector of the GBR averaged 44 [41, 48] adults per hectare in 2014.

Keywords: Bayesian analysis; CoTS; Data integration; Mark-recapture; Monitoring.

Grants and funding

This work was supported by funding from the Australian Institute of Marine Science and from the Queensland Government via an Accelerate Partnership under the Department of Science, Industry, Technology and Innovation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.