Keep your friends close and your anemones closer – ecology of the endemic wideband anemonefish, Amphiprion latezonatus

Abstract

Endemic marine species often exist as metapopulations distributed across several discrete locations, such that their extinction risk is dependent upon population dynamics and persistence at each location. The anemonefish Amphiprion latezonatus is a habitat specialist, endemic to two oceanic islands (Lord Howe and Norfolk) and the adjacent eastern Australian coast from the Sunshine Coast to Southwest Rocks. To determine how extinction risk varies across the limited number of locations where A. latezonatus occurs, we quantified ecological, biological, and behavioural characteristics at six locations and four reef zones. The abundance of A. latezonatus and its host anemones varied considerably throughout its range, with A. latezonatus abundance being very low at Sunshine Coast and Elizabeth Reef, low at Lord Howe Island and Norfolk Island, and moderate at North Solitary Island. This species was not detected at Middleton Reef, despite local abundance of their host anemones. Abundance of A. latezonatus was generally correlated with depth and host anemone abundance, from which we infer that extirpation risk is directly proportional to their host anemone population’s size. Consistent with this, A. latezonatus social group size was positively correlated with the number of anemones inhabited. A. latezonatus may be impacted by interactions and competition with other anemonefish species in shallow (< 10 m) waters, but competition has little effect in deeper water where population abundances are highest. Significant differences in population characteristics demonstrate a need for location-specific conservation strategies and identify the Sunshine Coast population as most vulnerable.