⚠️IMPORTANT WARNING FOR ALL DIVERS ⚠️ Fast-spreading lethal disease (potentially SCTLD) has reached Bonaire’s reefs.

[scubadada]

Hi @drrich2

The microbiology behind SCTLD appears to be very complex. You may have seen in the Bonaire forum a very recent original paper and a NOAA summary of it on this very topic

Fast Moving Coral Disease Alert on Bonaire

I know this was first discussed in the Fall of 2022......but here is the latest today from Bonaire Insider. https://infobonaire.com/fast-moving-coral-disease-alert-on-bonaire/?utm_source=mailpoet&utm_medium=email&utm_campaign=bonaire-insider-fast-moving-coral-disease-alert-on-bonaire-484

scubaboard.com

 

[drrich2]

Very interesting. I looked over summary/abstract content.

Considering the concern in this thread about ballast water as a potential vector, I wonder what the potential is for a vessel leaving from the U.S. far abroad to transmit it to distant lands.

I'd also like to know whether far distant coral populations, such as in Indonesia, are highly susceptible to SCTLD. Your NOAA strategy links shows they're already concerned about that risk.

Also wonder whether we're looking at a future where those 'coral tree' propagation structures we see at varied Caribbean locations (e.g.: Bonaire) will shift to farming pieces of corals resistant to SCTLD, in an effort to recolonize devastated reefs, and how long that'll take to have an impact.

 

[RyanT]

@drrich2, you already hit upon the difficulty.

Which is much harder than it sounds, because of the host of varied microbes in non-sterile reef water, creating a 'needle in a haystack' effect.

First, the ideal thing would be to take a sample, run tests, and isolate the causative infectious agents. For some diseases (maybe something like black band disease), it's easy to see the area that is dying and that makes it easy to see where you should be taking the sample. Microbiota from the dying area are good candidates for disease agents. For other diseases, it may not be so easy to see where the "disease front" is. You can sample corals and identify bacteria and viruses. However, the microbiome of nearly all organisms is diverse. So, just identifying microbiota doesn't necessarily tell you much about the causative agent.

Indeed, you can do controlled, infection experiments, but lots of them are likely to fail because you didn't get the right causative agent.

 

[rmorgan]

Drrich2, here’s what Hawaii’s thinking about it. https://dlnr.hawaii.gov/hisc/files/2022/10/Stony-Coral-Tissue-Loss-Disease-SCTLD.pdf

 

[Jake 10]

 

[Hoyden]

This remains bizarre to me. It's a big issue of widespread concern. With the disclaimer that arm chair quarterbacking is easy, I'm surprised nobody has replicated inducing it in lab settings that we know of.

It seems like an agency could set up a number of reef tanks with healthy but susceptible corals, then introduce suspect organisms and combinations of organisms in an effort to induce SCTLD. Given how quickly and pervasively this spreads, if I understand correctly, it seems like once you hit the right conditions, it'd be demonstrable.

A big problem with that is that viruses are so tiny and can be hard to detect. Even so, if you deliberately set up a SCTLD tank (e.g.: brought in infected wild corals) and used tank water to then infect other tanks, seems like water samples shown to convey the disease could be analyzed.

Which is much harder than it sounds, because of the host of varied microbes in non-sterile reef water, creating a 'needle in a haystack' effect.

@RyanT and others with a research background, do you have any insights on why SCTLD's causative organism or organism has been so hard to pin down?

P.S.: Analogous issue - did anyone ever figure out what was causing the sea star wasting disease off California? IIRC, that was a big concern awhile back, but I haven't heard of it for awhile.

The team at Florida Aquarium has been studying this (transmission in a lab setting) and has published some results. I will try to find this reference and post it. Sea Star Wasting disease is caused by Sea Star-Associated Densovirus and this discovery was a great collaborative effort.

​

 

[Jake 10]

 

[Jake 10]

 

[Jake 10]

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[Jake 10]

few good articles in this link

https://bonairereporter.com/current_issue/current.pdf