Fig 1.
Planulae from polyp dissection, histology, and planula release observation.
(A) Dissected and (B) longitudinal section of a polyp (July 18, 2013). (C) Planula larvae (pointed arrows) inside a fragment (June 29, 2015) and (D) a planula larva containing green fluorescence protein (July 4, 2015). Labels: Ec ectoderm, Ms mesoglea, Me mesentery, Sym Symbiodinium sp.
Fig 2.
Temporal changes in the proportion of colonies containing planulae of Seriatopora hystrix.
Five to ten colonies were observed through polyp dissection and histology at each sampling date. nd = no data.
Fig 3.
Temporal change of Seriatopora hystrix planula release.
The data is shown as percent of colonies releasing planulae (bar graphs) and number (log p+1-transformed) of planulae released (line graphs) of each colony between June 29 and August 31 (2013, 2015, 2016). The alphabet-number combination (e.g. A1, B1) represent lunar (A, first and B, second lunar cycles)-individual colony number that released planulae. New moon (black circles) and full moon (yellow circles) phases are plotted in the graphs.
Fig 4.
Circadian pattern of planula release of Seriatopora hystrix.
The data is shown as percentage of total planulae released during the 8 h monitoring intervals within the circadian cycle (24 h) per colony from July 1 to 3, 2015 (mean ± SE, n = 9). Significantly different comparisons are indicated with an asterisk.
Fig 5.
Percentage of Seriatopora hystrix planulae that settled on tiles and plastic jars over 6 days of observation after planula release (mean ± SE, n = 12).
Fig 6.
Mean daily seawater temperature from surface to 40 m depth between January 2013 and August 2016.
Seawater temperatures at surface (white circles), 35 m depths (light grey circles), and 40 m depths (dark grey circles) off Sesoko Island were recorded between January 2013 and July 2014. Seawater temperature at a shallow reef (1–2 m) at southern Sesoko Island was recorded between January 2013 and August 2016 (grey lines), while at study site (40 m) was recorded between April 2014 and August 2016 (black lines). The periods when colonies contained (red bars) and released planulae (blue bars) are plotted on the graph.
Table 1.
Seasonality, lunar and circadian periodicity of larval release of Seriatopora hystrix recorded from different geographic locations and different depths.
Data are ordered by latitudes from North to South. (-) indicates no available data. GBR: Great Barrier Reef. a No depth information; depth assumed as shallow. b Unpublished data from the same study suggest planula presence in the polyps throughout the year.