[Coral-List] The myth of 100% coral cover

BRUCE CARLSON exallias2 at gmail.com
Sat Mar 24 21:09:16 EDT 2012


After reading the subject line in your message, I recalled a reef in the Solomon Islands where I encountered 100% coral cover, or nearly so.  It was around a little island called Kisan in the Russells.  The Solomons has many areas of nearly pristine reefs (if I can use that term), especially in the more isolated areas.  Since I almost always have a camera with me, I shot some video as I "flew" over this reef carried along by a strong current.  It was one of the more amazing coral vistas that I have encountered.  The video was shot in 2006.  I tried to locate the same spot on my last visit to this island in 2009 but failed to reach it so I have no idea what the condition of the reef is like now.  Not many people get to see a reef like this so I thought I would share the video.  Here is the YouTube link:


FWIW, I have videotaped other reefs in the Solomons that once were similar in terms of coral cover but when I returned years later were dead due to the runoff from nearby logging operations.  That shouldn't be the case at Kisan which fortunately is far offshore.

Bruce Carlson

Dean Jacobson atolldino at yahoo.com 
Sun Mar 18 02:17:55 EDT 2012

I have a creeping/sinking baseline question.

On the coral-free-for-all, there was a comment that 100% coral cover is very rare, supported with a quote from a Veron email to the effect that "there is no reason why coral would so dominate the substrate"  In other words, total, 100% coral cover is a myth.  My experience is limited to a very few regions (Puerto Galera on Mindoro, where soft coral and crinoids dominate, and Palau and Maui), in addition to my home in the RMI.  My visits over the past decade to a dozen Marshallese atolls have convinced me that over 50% live cover is typical, on average (actually closer to 75%) and some reefs, such as along the southern shore of Rongelap Rongelap, 95-100% coral cover is the average for many hundreds of meters, excluding the deep, narrow grooves or canyons.  The reason for this, I would assume, is high recruitment, clean water and very limited disturbance/mortality (there has been an extremely low human presence on this atoll for several decades, due to
 fallout from the Bikini atoll Bravo H-bomb test).  

Such high coral covers appear to be rule in much of the Marshalls where storm damage, fatal bleaching, COTS outbreaks and human-associated pollution is minimal.

There are exceptions, such as Ebon's COTS-devastated lagoon, and Likiep atoll. where, i.e. in the South Pass, Microdictyon algae grows profusely, possibly due to upwelling nutrients; this green algae has vanished on Majuro in proximity to human settlement, it is clearly intolerant to pollution.   I have hundreds of images that document 100% coral cover in the RMI, and Zoe Richards has Rongelap survey data as well.

My question, in the global context, is the RMI an anomaly, in your experience?

Dean Jacobson
College of the Marshall Islands

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