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First record of the coral-killing sponge Terpios hoshinota in the Maldives and Indian Ocean

The cyanobacteriosponge species Terpios hoshinota Rützler and Muzik, 1993 (class
Demospongiae: family Suberitidae) is noted for its ability to overgrow living corals, and
occasionally undergoes large outbreaks capable of killing the majority of hard corals on
afflicted reefs (Bryan 1973). Originally described off Guam, this sponge has been reported
from the subtropical northwestern Pacific Ocean (Liao et al. 2007, Reimer et al. 2010), the
Great Barrier Reef (Fujii et al. 2011), and off Indonesia (de Voogd et al. 2013); it is theorized to
be spreading its range in western Pacific waters (Liao et al. 2007).
During recent biodiversity surveys at the Faafu Atoll, Maldives, thin, black, encrusting
sponges were observed overgrowing live Porites, Acropora, Cyphastrea, Montipora, and
Pavona coral colonies at 13 different locations at depths from 7 to 24 m. Panel A shows an
image of T. hoshinota (dark gray center portion) overgrowing Pavona coral (yellow-brown
peripheral portion). Panel B is a close-up showing the expanding edge of T. hoshinota (top)
overgrowing Porites coral (bottom) (scale bars for both A, B approximately 2 cm). Analyses
of specimens’ spicules and mitochondrial DNA sequences of cytochrome oxidase subunit
1 (COI) confirmed the identity of these sponges as T. hoshinota. Spicules matched those
reported for T. hoshinota and obtained COI sequences (length = 626 base pairs) that were
either identical (4/5 examined specimens) or with 1 synonymous base pair difference (1
specimen) from previously reported sequences from Taiwanese specimens (GenBank
Accession Number KJ008098).
This is the first record of T. hoshinota from the Maldives and by extension from the Indian
Ocean. Although monitoring is needed to ascertain the full extent of T. hoshinota’s presence
in the Maldives, this report demonstrates that this species is much more widely spread than
previously thought. Either T. hoshinota is expanding its range rapidly or the extent of the
original range of this species has been underestimated. Population level analyses are needed
to answer whether this species is undergoing rapid distribution expansion.



  • Bulletin of Marine Science