N. GBR - Blue (AU4331)

Setting

The site sits in a Habitat Protection (Blue) Zone, where line fishing is permitted.

General benthic features

Two downward frames show the problem plainly: pavement and rubble under a gray film of sediment, with small encrusting and mounding colonies, favids, a ridged plate coral, scattered juveniles, holding on in the gaps rather than forming a continuous cover (e.g., Image 1, Image 3).

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The exceptions are two showpieces: a large brain coral, its meandering valleys clean and healthy alongside a pale pink mounding neighbor, and a big clam wedged into the pavement with the GRE transect chain and its numbered tags laid across it (e.g., Image 4, Image 5).

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The bright spot was recruitment, unusually high, with many small young colonies. Much of the hard structure was blanketed in soft corals and sea fans, with a stretch of dead staghorn framework and a patch dominated by fleshy macroalgae. Porites was the most common coral genus on this station's transects (6.2% of the benthos), followed by Acropora, Astreopora, Galaxea, and Heliofungia (1.3% each) and Cyphastrea, Favia, and Lobophyllia (1.0% each); bare substrate covered 13%, behind turf (30%), the largest non-coral class. Among the algal classes on this station's transects, turf (30%) led, followed by sediment-laden turf (23%) and macroalgae (6.2%).

Coral cover

• Reference: Khaled bin Sultan Living Oceans Foundation, Global Reef Expedition (in situ transect)
• The point-count survey put live cover here at 20%, on a low, ridge-like reef cresting within 3-4 m of the surface but holding most of its life at 5-10 m.
• Transect mean 20 ± 4.7% SE (n = 6 transects; Living Oceans Foundation per-transect benthic data); the headline above is the expedition's station value.

Stressors

One close-up is pure dead staghorn Acropora, its branches furred over with filamentous turf (e.g., Image 2).

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One stark-white branching colony with a crown-of-thorns starfish on its edge is recently dead, its bare skeleton still clean and white; the cause is not stated (e.g., Image 12).

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Four crown-of-thorns starfish were logged.

Comparisons with other data

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

Dive record

Anderson's first dive on this unnamed mid-shelf reef, on 8 September 2014, ran into thick, silty water, 3-4 m of visibility, and every photograph from it is shot close.