Fast Moving Coral Disease Alert on Bonaire

[tursiops]

(1) there is actual evidence implicating ballast water in the spread of SCTLD

And there is negative evidence. Your map of the spread on Grand Cayman is anything but supportive of a ballast-water source.

 

[rmorgan]

And there is negative evidence. Your map of the spread on Grand Cayman is anything but supportive of a ballast-water source.

Indeed. But it has to get from island to island somehow, and what makes sense to me (but is speculative) is that one way or another, it came by ship (ballast water, hull, mooring line, head discharge, who knows), and spread locally by current, fish, fishing boat, diver, who knows. @Joneill's right that the Grand Cayman history makes divers as the cause of spread. But maybe it came by ship and then moved from sector to sector due to dive gear--a known unknown. It is known that ballast water is implicated, but beyond that--a guessing game.

 

[tursiops]

Indeed. But it has to get from island to island somehow, and what makes sense to me (but is speculative) is that one way or another, it came by ship (ballast water, hull, mooring line, head discharge, who knows), and spread locally by current, fish, fishing boat, diver, who knows. @Joneill's right that the Grand Cayman history makes divers as the cause of spread. But maybe it came by ship and then moved from sector to sector due to dive gear--a known unknown. It is known that ballast water is implicated, but beyond that--a guessing game.

Best evidence is that the lionfish spread by currents, not ships.

We'll see which sites on Bonaire get infected next....unfortunately, that is likely to the north of the infected zone now. And there are NO cargo or cruise ships on Klein.....

 

[scubadada]

Indeed. Given that (1) there is actual evidence implicating ballast water in the spread of SCTLD, and (2) cargo vessels carry much more ballast water than cruise ships, there are plenty of potential sources, and no actual reason to think the disease arrived via one or the other.

As to the efficacy or not of precautions--I suppose the person who put the first lionfish or two into the Florida coastal waters thought, if they thought at all . . . "what could go wrong?" STINAPA sets the terms and conditions for use of the dive sites, and while it's fine to second-guess, it's not ok to disregard. The stakes are high enough as it is.

Hi @rmorgan

We had this discussion before Fast Moving Coral Disease Alert on Bonaire The transmission by infected water was a laboratory study. Fast Moving Coral Disease Alert on Bonaire As I said before, I could easily be wrong, but have not seen evidence of transmission of SCTLD by ballast water.

Unfortunately, for Bonaire, the exact mechanism of transmission is no longer applicable. I have seen no evidence, one way or the other, to support specific measures to delay or prevent spread once an area is infected. Application of antibiotic-epoxy paste to individual corals may be useful, but is not a solution.

 

[Joneill]

Indeed. But it has to get from island to island somehow, and what makes sense to me (but is speculative) is that one way or another, it came by ship (ballast water, hull, mooring line, head discharge, who knows), and spread locally by current, fish, fishing boat, diver, who knows. @Joneill's right that the Grand Cayman history makes divers as the cause of spread. But maybe it came by ship and then moved from sector to sector due to dive gear--a known unknown. It is known that ballast water is implicated, but beyond that--a guessing game.

Just to be clear- my point was that Grand Cayman’s experience with the rapid spread of SCTLD during their strict pandemic lockdown points to divers NOT being the cause of spread.

I was just watching fish feeding/pecking at infected brain and star coral in Aruba today. The same fish then moved over to peck at healthy brain and star coral today. I’m no marine biologist, but 1 likely mechanism of spread is pretty obvious to me - and it’s not divers passing a few feet above the corals.

 

[tursiops]

The most cited article about ballast water being the culprit is attached. If you read it it, it does NOT say ballast water is the culprit in transmitting SCTLD. Rather, it says, ballast water could be the culprit, among other possibilities, and then caveats:

Ballast Water Movement and SCTLD Patterns​

United States BW management data and Caribbean-wide SCTLD report information are being used in projects to evaluate BW as a potential vector for SCTLD. However, such analyses are correlative and often do not yet consider other possible mechanisms or interactions. Correlations between disease incidences and ship movements or BW discharge are useful, but not sufficient to definitively identify ships as vectors. Importantly, given the extensive maritime traffic in the Caribbean, including both ships and recreational vessels, we urge caution in drawing conclusions based on apparent correlations, in the absence of experiments demonstrating causation.​

​

A preliminary analysis in 2019, including >36,000 BW discharge and management records in the NBIC, spanning Sep 7, 2013–Aug 6, 2020, detected no clear relationship between BW discharges and SCTLD occurrence in United States waters, since sites with SCTLD varied in BW discharge histories, including some with no reported discharge.​

 

[tursiops]

If you like reading original research papers, rather than abstracted news articles based on them, here is a collection:

Stony Coral Tissue Loss Disease in the Caribbean

Starting in September 2014, an extremely high-prevalence outbreak of a white plague-like disease (now referred to as Stony Coral Tissue Loss Disease) was observed in southeastern Florida. The first signs of active disease were observed near Virginia Key, Florida, and after five years had spread...

www.frontiersin.org

 

[Charred]

Ok, but where is the evidence that divers spread it and any of the precautions people recommend for divers halt the spread?

I stand by my statement there is no scientific basis for any of the precautions being recommended and will gladly stand corrected when referenced a peer reviewed article.

 

[tursiops]

It is called the Precautionary Principle. Because there is no consensus on how it is spread, you do what you can to mitigate it.

 

[rmorgan]

The most cited article about ballast water being the culprit is attached. If you read it it, it does NOT say ballast water is the culprit in transmitting SCTLD. Rather, it says, ballast water could be the culprit, among other possibilities, and then caveats:

Thank you, tursiops. I did read it late last year. Undercurrent recently quoted the lead author: “'The results suggest that ships' ballast water poses a threat to continued spread and persistence of SCTLD throughout the Caribbean and potentially to reefs in the Pacific, and that the established treatment (UV) and testing standards may not mitigate the risk of disease spread,' said Michael Studivan, the study's lead author.” I don't see any discussion of other possibilities, but the ballast thesis is plausible, and I'm not not aware of other hypotheses.
But as to Bonaire, it really doesn't matter how it got there; it's there.

With respect to the questions around supporting evidence for the efficacy of decontaminating before diving in another zone, which is a current issue on Bonaire, there is reasonably-compelling evidence that local activity, whether boats, divers, or something else, can't be dismissed out of hand. The spread map from February 2021 (which @Joneill posted in June 2021), shows that as the infection spread across the north shore, it also appeared at isolated spots around the east end and Georgetown--locations miles away from the main spread of the disease, where there were public moorings, and hence smallcraft, divers, snorkelers, fishers, etc. It seems to me that these findings alone more than justify STINAPA's imposition of its current policies, and that human activity of whatever sort is a more likely explanation than fish or turtles swimming, and not easily reconciled with ocean currents.