Grand Cayman coral - white like snow

[Divedoggie]

What I saw in Little Cayman was not SCTLD (they claimed it was not present in Little or Brac - only around Grand Cayman (though hard to believe that given proximity) - it was bleaching due to persistent high water temps.

I dove GC one year ago, before the high temps of this past summer. Everything was already dead.

It isn’t a singular issue. It isn’t solely bleaching, or solely SCTLD. There are a multitude of factors, including high plant nutrients and phosphates in the water, due to fertilizers, treated waste and untreated waste. Lionfish can devastate the algae eaters on the reef in a matter of weeks. Algae on the reef blooms and there’s no remedy for that because the small algae eater fish are gone.

Haiti has over 12 million inhabitants and not one working sewage treatment plant.
Hurricanes and severe storms, poor diver skills, overfishing, plastics and pollution, probably most importantly, the loss of mangroves due to development all mix together to put pressure on an already fragile ecosystem.

The Caymans are only one example of this problem. It is epidemic across the Caribbean

 

[tridacna]

Once a stony coral loses its zooxanthellae, it is unlikely to survive. Those patches of white corals eventually get covered in red or purple cyanobacteria, giving rise to the illusion that they are once again alive. Unfortunately, nothing could be further from the truth. VERY occasionally, within a week or so, the coral may be recolonized by zooxanthellae and could possibly regrow.

 

[vincent54]

Depends on the coral species and the type of clades that sisters with the coral. Some corals can survive months bleached. The bleach tolerant species are well documented. Branching corals are the most fragile.

2019 was a massive bleach in Cayman and most of the coral survived quite well.

 

[tridacna]

Depends on the coral species and the type of clades that sisters with the coral. Some corals can survive months bleached. The bleach tolerant species are well documented. Branching corals are the most fragile.

2019 was a massive bleach in Cayman and most of the coral survived quite well.

Interested: Which species are the most resistant. Acropora?

(Interesting word: clades. I had to look that up). .

 

[tursiops]

Branching corals are the most fragile.

Which species are the most resistant. Acropora?

Most Acropora species ARE a branching coral....

 

[tridacna]

Most Acropora species ARE a branching coral....

Thanks Professor Obvious. Research seems to indicate that most Acropora seem to recover somewhat. I’m curious as to which is is the most resilient.

 

[vincent54]

Thanks Professor Obvious. Research seems to indicate that most Acropora seem to recover somewhat. I’m curious as to which is is the most resilient.

https://www.ncei.noaa.gov/data/oceans/coris/library/NOAA/CRCP/project/535/ESTUARINE-COASTAL-AND-SHELF-SCIENCE-2012-van-Hooidonk.pdf

Good explanation for the Caribbean corals. Most of the brains look good now that the water is cool

 

[iointerrupt]

We were in Coz last week and going to Curaçao again next

Things not so great in Curacao. In August everything looked perfect, now in November there's clearly been a large die-off. By my eye, maybe 25%, and worse the further north you go. Water temperature is still around 85F / 29C, all the way to the bottom. Was surely warmer in September/October.

To me it looks like bleaching, but I don't know enough about SCTLD to argue the point. Brain corals, lettuce corals and pillar corals all pure white.

Pencil corals and staghorn corals seem unaffected. Saw an interesting elkhorn coral at Director's Bay, entire top side was white, but the bottom faces were still orange.

 

[tridacna]

https://www.ncei.noaa.gov/data/oceans/coris/library/NOAA/CRCP/project/535/ESTUARINE-COASTAL-AND-SHELF-SCIENCE-2012-van-Hooidonk.pdf

Good explanation for the Caribbean corals. Most of the brains look good now that the water is cool

Looks like Montastrea and Porites are the most resistant to bleaching. Problem is how to distinguish between that and SCTLD. That study was pre-SCTLD. I suspect that brains were affected greatly by SCTLD.

 

[tursiops]

Looks like Montastrea and Porites are the most resistant to bleaching. Problem is how to distinguish between that and SCTLD. That study was pre-SCTLD. I suspect that brains were affected greatly by SCTLD.

Bleaching Susceptibility | Reef Resilience

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