After conducting coral spawning experiments since 2013 in wet-labs – a total of 13 coral spawning events – I finally had the opportunity to see it for the first time in the wild. The chance of seeing spawning was uncertain, as water temperatures for the time of year were unseasonably low, and we had heard very few corals had developed pigmented eggs. Still, Magnetic Island corals had spawned without fail in October since I can remember, and so we decided that at worst we would get a few nice days holiday. There wasn’t much to lose.
The first night was really a night designated to test equipment and find a good site, but within a few minutes of decent, we saw the first setting corals. The first coral I observed spawning was at ~8 pm, and various Acropora and Montipora spp. spawned past our ascent time of 9:30pm. There was lots still set as we exited the water.
Note: I haven’t done any editing on the photos so I can keep a reference of how things looked underwater just in case I want to work on some of these spp. in the future. All photos taken with a dive-torch and a TG-6.

The first coral I saw setting around 8pm.

I find this one interesting. The branches have almost no egg-sperm bundles, but are super-dense between the branches.

The coral-eating Drupella snail

The zooplankton attracted to the light were nuts. …and had a good sting.
On the second night there was, suprisingly, no spawning. It still made for a fun night-dive but there was hardly the flurry of activity from the previous night. The plankton, crabs, sharks and fish had mostly disappeared, worn out from the night before.

This blenny apparently likes to sleep above the waterline.