НАХОДКА БОЛЬШОЙ КЛОНАЛЬНОЙ ГРУППЫ ОБЛИГАТНО СИМБИОТИЧЕСКОЙ АКТИНИИ ENTACMAEA QUADRICOLOR БЕЗ РЫБ-СИМБИОНТОВ – ВЛИЯНИЕ УСЛОВИЙ СРЕДЫ

Abstract

The large clonal group of the obligate host sea anemone Entacmaea quadricolor (Leuckart in Ruppell et Leuckart, 1828) (Anthozoa, Actiniaria, Actiniidae) was found at the station with coordinates 20°44’09.0’’ N and 107o08’55.8’’ E in the water area of Cat Ba Islands in the Tonkin Gulf. This clonal group was located on stony bottom (surrounded by sands) at a depth of 4 m, had an area of about 15 m², consisted of hundreds of host sea anemones, but was not inhabited by anemonefishes. Large clonal groups of host sea anemone E. quadricolor uninhabited by anemonefishes were not previously noted in other parts of the coastal waters of Vietnam. Comparison of the investigated water area with the waters of Hong Kong showed their similarity in temperature and hydrological parameters with more turbidity in Cat Ba. In the waters of Hong Kong huge fields of host sea anemone E. quadricolor are marked by an extremely low density of anemonefishes: 0.07–0.26 fishes per m². From this it follows that the environmental conditions in the waters of Hong Kong and especially of Cat Ba Islands are extreme for the habitat of anemonefishes, even for Amphiprion clarkii. Probably single specimens of anemonefishes can be found in Cat Ba region when more extended studies of large clonal groups of the host sea anemone E. quadricolor are curried out.