Fig 1.
Daytime spawning corals across the Gulf of Thailand.
Dataset includes present surveys and previous records from the Western Gulf of Thailand. Coloured section of charts indicate briefest quantity of minutes and hours after sunrise (out of a total 24) at the start of spawning, with latest recorded start of spawning for each coral and location indicated in black. Outer ring of the pie chart indicates the total months of the year during which spawning was identified per species per location. Sites which were surveyed but where no spawning was recorded are identified as null data. Legend provides an example of Pavona explanulata indicating earliest start of spawning period to be approx. 9 hours and 50 minutes after sunrise, with the latest start of spawning being approx. 10 hours and 50 minutes after sunrise. Legend indicates all spawning records to be in September and October. Pie charts without black sections indicate only a single spawning date recorded or identical spawning onsets. Detailed timings accessible in S1 Table. The basemap incorporates provincial boundary data from SimpleMaps [63,64]. (CC BY 4.0).
Fig 2.
Photographs of daytime gamete release of corals recorded along the Eastern Gulf of Thailand.
A) Egg release by partial colony of Pavona varians (scale bar 50 mm); B) Simultaneous egg and sperm release by a hermaphroditic colony of P. varians (scale bar 50 mm), red box indicates portion zoomed in for (A) to more easily differentiate egg release from sperm; C) Near-transparent egg-release (red ellipse for example) by polyps of P. explanulata (scale bar 10 mm; photo by Thomas Thana Real); D) Whole-colony sperm release by P. explanulata (scale bar 50 mm); E) and F) Photos taken five seconds apart before and during gamete release by Cycloseris sp. (scale bar 50 mm); G) Sperm release by Dipsastraea sp. (scale bar 50 mm).
Fig 3.
Plots of spawning timing of all recorded scleractinian corals, and null data, along the Chonburi, Rayong and Trat provinces of the Gulf of Thailand between 2021 and 2024.
A) Records of spawning in hours after sunrise plotted against days after new year with monsoon period preventing surveys indicated in the middle of the year; B) Records of spawning in hours after sunrise against days from full moon.
Fig 4.
Plots of spawning timing for Pavona varians and P. explanulata along the Gulf of Thailand (by province) and Cambodia between 2021 and 2024.
Spawning timing of P. varians with hours after sunrise plotted against (A) days after new year (emphasising the second half of the year) and (B) days after full moon, and P. explanulata showing hours after sunrise plotted against (C) days after new year and (D) days after full moon.
Fig 5.
Plots of spawning timing for Pavona corals across the globe by species and location.
A) Records of spawning in hours after sunrise plotted against days after new year; B) Records of spawning in hours after sunrise against days from full moon.
Fig 6.
Spawning timing of Pavona corals across the globe, by species.
Charts indicate briefest quantity of minutes and hours after sunrise (out of a total 24) at the start of spawning. Outer ring of the pie chart indicates the total months of the year during which spawning was identified per species per location. Legend provides an example of Pavona clavus indicating earliest start of spawning period to be approx. 9 hours and 50 minutes after sunrise, with all spawning records to be September and October. Detailed timings accessible in S1 Table. The basemap incorporates provincial boundary data from SimpleMaps [63,64] (CC BY 4.0).