Deep Finding of Anemonefish Amphiprion frenatus (Pomacentridae, Amphiprioninae) in Symbiosis with Sea Anemone Entacmaea quadricolor (Cnidaria, Actiniaria) on Reefs of the Spratly Archipelago (South China Sea)

For the first time, a description of the depth distribution of the anemonefish Amphiprion frenatus in symbiosis with the sea anemone Entacmaea quadricolor on six reefs of the Spratly Archipelago, located in the open waters of the South China Sea, has been given. In the study area, A. frenatus begins to occur in the host sea anemone E. quadricolor from a depth of 4 m; the main number of sea anemones inhabited by A. frenatus was recorded in the depth range of 8-30 m. Deeper, the sea anemones E. quadricolor inhabited by A. frenatus occur singly up to a depth of 45.9 m-this lower limit of occurrence of A. frenatus is absolutely extreme for this species and by 3.53 times exceeds the maximum depth of occurrence of A. frenatus (13 m) previously indicated for the entire range of this species, including the coastal waters of Vietnam. The deep-sea occurrence of A. frenatus on the reefs of the Spratly Archipelago cannot be explained by such hydrophysical parameters as the transparency and temperature of the waters of this area.

Automated summary

This study provides the first description of the depth distribution of Amphiprion frenatus in symbiosis with Entacmaea quadricolor in the Spratly Archipelago. It was found that the majority of A. frenatus inhabited sea anemones between 8-30 meters, with some recorded as deep as 45.9 meters. The deep-sea occurrence of A. frenatus cannot be explained by hydrophysical parameters.