Coral Reefs of the World-part 226: Monkman Reef, far northern Great Barrier Reef (Australia)

Monkman Reef is a mid-shelf reef in the far northern Great Barrier Reef, Queensland, Australia, inside a no-take Marine National Park ("green") zone.

Max. survey depth=18.4 m

Coral cover (2014)=68±13% (mean±standard error)

Coral Health Index (CHI; 氣)=2.75/5

We surveyed Monkman Reef on 20 September 2014 during the Khaled bin Sultan Living Oceans Foundation's Global Reef Expedition. One day each was spent at Milman (2014-9-18; n=6 sites: AUMM85-90) and Monkman (2014-9-20; AUMO97-102) Reefs, with an intervening day (2014-9-19) split between unnamed reef 39 (n=2 sites: AUUN95-96) and unnamed reef 25 (n=4 sites: AUUN91-94). Pavona cactus and Porites cylindrica dominated cover in the shallows (4–8 m). At 10–16 m, coral was patchier, with branching Acropora, massive Porites, and plating corals. We saw no bleaching, disease, or crown-of-thorns starfish. There were five or six gray reef sharks patrolling the site, along with two huge groupers and a resident stingray.

Our survey came about 18 months before the 2016 mass bleaching event, which hit the far northern GBR hardest (Hughes et al. 2017, Nature 543: 373–377). Since then, heat stress has become routine: NOAA Coral Reef Watch's Far Northern GBR virtual station recorded severe heat stress (8°C-weeks or more) in four of the last five years, 11.3°C-weeks in 2021, 11.8 in 2022, 12.2 in 2024, and 13.8 in 2025, with 9.4°C-weeks so far in 2026. A 2026 model of bleaching on Australian reefs found that heat stress drives bleaching, but its effect weakens farther from land, and bleaching is less likely in deeper, more turbid, or naturally more variable water; accounting for these factors predicted bleaching better than heat alone, especially in the far north (Liu et al. 2026, Coral Reefs 45: 2269–2286).