Coral Reef Diagnostics

N. GBR - Blue (AU3995)

Khaled bin Sultan Living Oceans Foundation — Global Reef Expedition
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Part of the regional summaries: Australia (GBR) - Far North: Blue stations (Habitat Protection Zone reefs) and Australia (GBR)

05
Coral Health Index: TBD
Photo: Anderson Mayfield/Coral Reef Diagnostics
Country
Australia
Survey date(s)
2014-09-19
Coordinates
-11.2430, 143.2520
Coral cover
41%
Benthic transects+photo-quadrats
Observations
crown-of-thorns
Heat stress
Today’s heat load
25.2°C0.0°C-weeks
3 Oct 2026 · No heat stress
5-year thermal stress load
5-year mean max. degree heating weeks (DHW)
11.1°C-weeksi
2021–2025
NOAA Coral Reef Watch — Far Northern GBR virtual station
i 5-year mean max. DHW is the mean of the annual maximum DHWs over the five complete years named above, not conditions today.
More infoFar Northern GBR (NOAA CRW virtual station)
Photographs
35
2 shown on this page
Site summary

A very murky dive, with 2-3 m visibility and silt settling over nearly everything, and a reef that shifts from a near-monoculture of plating Leptoseris/Pavona-type coral at 20 m to Goniopora and finger Porites in the shallows. Anderson noted that the once-common Pavona cactus had mostly died and been replaced by finger Porites. Surveyed on the Living Oceans Foundation's Global Reef Expedition.

Max. depth dived
21.5 m
dive-log maximum
Sea surface temp. (satellite)
25.0°C
satellite sea surface temperature (SST) on the survey date (NOAA Coral Reef Watch, Far Northern GBR), not an in-water reading; it is the warmest-pixel (90th percentile) reading in the station area and can run 1–1.5°C above the reef
Bottom time
62 min
in at 16:20

Five other CRD dive sites within 5 km shown in orange — click a marker to open its page.

🗺 Detailed map of the Global Reef Expedition dive sites, Milman, Monkman, Parkinson, and unnamed reefs, northern Great Barrier Reef (Khaled bin Sultan Living Oceans Foundation; opens in a new window)

Site description

Setting

A very murky dive — just 2-3 m of visibility and thick suspended sediment settling over almost everything. The expedition's own site table classifies AU3995 as a sheltered mid shelf reef on an intermediate aspect.

General benthic features

Down at 20 m the reef is nearly a monoculture of Leptoseris or Pavona cactus; move up to 8-10 m and Goniopora, Porites rus, and P. cylindrica take over, continuing into the 5-7 m band with massive Porites mixed in. Both photographs are close views that show the sediment load directly: a knobby massive colony with fine polyps, its surface draped in pale strands of silt and mucus (e.g., Image 1), and a tan colony of flattened, fused finger-like branches, studded with the round openings of tube-dwelling animals and strung with silt (e.g., Image 2).

1Image 12Image 2

Montipora was the most common coral genus on this station's transects (18% of the benthos), followed by Porites (9.8%), Goniopora (6.2%), Acropora and Pavona (1.7% each), and Montastrea and Pocillopora (1.0% each); bare substrate covered 31%, the largest non-coral class. Among the algal classes on this station's transects, sediment-laden turf (28%) led.

Coral cover

Stressors

Anderson noted that Pavona cactus appears to have been common here but had mostly died and been replaced by P. cylindrica. One deep transect was simply "covered by silt," with only Goniopora and a handful of other species clinging on. A lone crown-of-thorns starfish was also logged.

Fish and other fauna

Paired fish transects recorded about 25 fish species per transect and about 9.5 kg per 100 m2 of biomass.

Comparisons with other data

No prior survey data from this site. If you would like to share yours, please email us.

Data & links

All images from Coral Reef Diagnostics. Data are from the Khaled bin Sultan Living Oceans Foundation Global Reef Expedition and Coral Reef Diagnostics.

© Coral Reef Diagnostics.