Journal ID : AMA-05-09-2021-10686
[This article belongs to Volume - 52, Issue - 01]
Total View : 443

Title : No mass synchronous spawning of reef corals in Nha Trang bay, Vietnam (the western South China Sea)?

Abstract :

Nha Trang bay is located in the south-central waters of Vietnam and considered as part of the most diverse region within the western South China Sea. According to oceanographic studies, this coastal area is not influenced by cold water mass from the north in winter but subjected to summer upwelling. Specimens for the study on coral spawning of four species were collected at Hon Mieu Island (12°11'37.31"N and 109°14'1.82"E) and 2 nearby sites during 2016 – 2019. Mature eggs of branching Acropora florida and A. robusta were observed inside coral colonies in the time before to after the full moon of late March to early April in 2018 and March in 2019. Meanwhile, the tabulate coral of A. hyacinthus spawned in the period after the full moon of March 2019. The total time of spawning periods of the three Acropora species is around 10 days. The spawning time of the massive coral of Dipsastraea palida was one month later than that of branching Acropora corals, during the time before and after the full moon of late April to early May in 2018 and April 2019 with the mature period around a half month. Observation on the ratio of mature (pigmented) eggs by time showed possible multispecific spawning of some Acropora corals. Further analysis on spawning periods of 3 Acropora species and one faviid species indicated that spawning of corals in Nha Trang bay could occur for a long time and at different periods from March to May but not concentrated in short period (1 to 3 days) in the same time as occurrences of mass synchronous spawning of corals in many areas in the Indo – Pacific.

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