A screenshot notification of the warning levels for coral bleaching, received on 24 January 2025
Last week, the chance of coral bleaching in Norfolk Island’s inshore lagoons was raised from ‘Watch’ to ‘Warning’. Last year, we rose to Alert level 2 by February (these things happen fast, over a matter of a week or two), but fortunately, although we did get bleaching, it was nowhere near as bad as it could have been. I am keeping fingers crossed that this happens again this year. Although I am not sure we are going to get off so lightly this time.
In this post, I’ve included the change to our Alert level (right) and three images of the temperatures/bleaching for 2020–2021 (when we last had severe bleaching), 2023–2024, when the temps were up there but we got away with it, and 2024–2025 (bottom of this post). If you want to take a look at the Global Reef Watch site and have a look at the various graphs etc, go here: Coral Reef Watch.
It is interesting that back in 2020–2021, the temperatures were not as high as they were last year, yet the bleaching was bad. A lot has to do with the timing of the tides. When we get those low low tides in the hottest part of the day for a stretch of a few days, that is when it can get serious. So we need a break in the weather before those happen in a week or two.
So why do I worry about water quality all the time when bleaching seems inevitable these days, so the reef is probably doomed anyway?
Slaughter Bay, Norfolk Island, March 2020
Well, think of being in a boxing ring for the fight of your life. One punch and you can get back up. Two punches and it gets a bit harder. By three punches you are out on the floor with stars before your eyes and it is becoming increasingly difficult to get back up.
We need to stop punching the reef. We need to remove some of those stressors so it is more resilient for the inevitable blows that are going to come its way. It’s not difficult. We know what the problem is (thanks to CSIRO’s Water Quality report released in October 2024, which confirmed all the other reports and observations going back to the 1960s), we just need to act. And now it really is urgent.
The two photos in this post are of some bleached coral in Slaughter Bay, March 2020. Our most vulnerable colonies seem to be the pretty lace corals (Pocillopora), followed by the plate corals (Monitpora) and the porites.
The CSIRO report can be found here: Norfolk Island Water Quality Assessment. This report should be read together with the report on acid sulphatre soils, here: Acid Sulfate Soil Management in the Kingston and Arthur’s Vale Historic Area (KAVHA) on Norfolk Island.
Read more about the CSIRO report, here: Taking stock. Which way from here?
