Seven species of Acropora stony corals have been recorded in the Hawaiian Archipelago. All species but the table coral Acropora cytherea are currently restricted to the central Northwestern Hawaiian Islands, from Necker Island to Pearl and Hermes Atoll (Asher et al. 2012). In the Main Hawaiian Islands, several small colonies of A. cytherea have been reported from Kaua‘i and a single large colony (100 × 60 cm) was recently sighted off O‘ahu (Kosaki et al. 2013). There have been no historical reports of any Acropora species occurring around the Island of Hawai‘i, the southernmost island in the archipelago, nor were any observed in over 4,300 coral reef monitoring/research dives over the past 14 years.

In April 2013 during the course of a reconnaissance dive utilizing diver propulsion vehicles, we came across a large number of Acropora gemmifera colonies in South Kona on the West Coast of the Island of Hawai‘i. Visual identification was subsequently confirmed by Narrissa Spies (personal communication) based on sequencing of the Pax-C 46/47 nuclear intron.

A total of 75 A. gemmifera colonies occurred in an approximately 50-m stretch of reef in depths ranging from 3 to 9.8 m (mean = 5.9 m, median = 5.8 m). Colonies ranged in size from small encrusting forms (Fig. 1) to large upright digitate colonies (Fig. 2), the largest of which (Fig. 3) was 71 × 68 × 75.5 cm (LWH). Based on linear growth rates for a morphologically similar species, Acropora humilis, in the Red Sea (Attalla et al. 2011), we can speculate that A. gemmifera has been present in this area for at least 80 years.

Fig. 1
figure 1

Acropora gemmifera encrusting form

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Fig. 2
figure 2

Multiple colonies of Acropora gemmifera

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Fig. 3
figure 3

Large colony of Acropora gemmifera with white tumor (growth anomaly) just below center of image

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