, Volume 31, Issue 3, p 821
Date: 24 Apr 2012

Mass stranding of crown-of-thorns starfish

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In late January 2012, 806 individuals of crown-of-thorns starfish (COTS) Acanthaster planci were stranded on a 300 m section of a sandy beach at Urasoko Bay, Ishigaki Island (southern Japan) (Fig. 1). Additional strandings were observed about two times per week in the same point (approximately 1,000 and 300 individuals, respectively). Their average diameter was 23.35 ± 3.64 cm (mean ± SD; N = 100). These COTS had been observed moving on the sand in shallow water near the beach 4 or 5 days before mass stranding, indicating that they had actively aggregated in the inner part of the bay, not carried there by currents after their death. In Urasoko Bay, adult COTS were common in 2009, and there was an outbreak of juvenile COTS (the diameter was 3–4 cm; the density was more than 1 COTS m−2) on the outer reef slope (2–10 m depths) in the summer of 2010. There, where Acropora corals comprised 20–60 % coverage before the outbreak (Suzuki et al. 2012), all families present were seriously damaged ...