[Coral-List] SCTLD on Bonaire

[Austin Bowden-Kerby]

Dear friends dealing with SCTLD,

As Four-spot Butterflyfish are now proven as a primary vector of SCTLD, I
would consider removing these predators around pillar corals.  While this
approach may seem reactionary and unproven to some, consider that this
species of butterflyfish are not in the least bit endangered.  The
precautionary principle of science should be turned on its head when
extinction risk is involved: Guilty until proven innocent.  As the
Dendrogyra corals are so precious, I personally would not wait for more
data- I would assume that these fish are the primary vector, as this is
apparently the only proven vector so far.

We had a staghorn coral nursery in Roatan collapse due to a rapid tissue
loss disease facilitated by a pair of four-eye butterflyfish way back in
2005, and the same problem was observed in Belize several years later.  At
the very least, judge for yourself: monitor for the presence of the fish
and observe their preferential feeding on diseased colony areas, and then
record these same individuals moving and picking at healthy tissues (which
a week later will likely be diseased).  But I personally would not wait for
the obvious negative outcome.

Perhaps overfishing of butterfly fish predators might be a factor in the
spread of this disease in the Caribbean, and if so, the ecologically
balanced reefs with the lowest abundance of four-eyed butterfly fish will
retain some pillar coral colonies?

Here in the Pacific, we have had horrific problems with Melon or Redfin
Butterflyfish stripping all the tissues off of Acropora corals when we
transplanted Acropora corals to reefs where the corals were absent, or
present only within Stegastes farmerfish territories (the farmerfish chase
the butterflyfish away).  We speared out the butterflyfish to good effect.
But then we found that over-abundant Parrotfish were also a horrific
problem, in addition to COTS.  The farmerfish were found to effectively
chase all three of these predators away.  In spite of some negative costs
associated with Stegastes on Acropora corals, we are now looking into using
farmerfish as "guard dogs" to protect the corals, as we work to
re-establish Acropora corals on ecologically imbalanced reefs.  Dead reefs
very low in coral cover, on the other hand, do not harbor these three coral
dependent predators, nor do they harbor diseased corals, but these reefs
are often impacted by algal overgrowth, so small outplants fare poorly. So
we developed new approaches using "nucleation patches" and planting corals
to structures that quickly restore fish abundance, which in turn reboot
natural processes (links below).

Regards,

Austin


Austin Bowden-Kerby, PhD
Corals for Conservation
P.O. Box 4649 Samabula, Fiji Islands
https://www.corals4conservation.org
Publication on C4C's coral-focused climate change adaptation strategies:
https://www.mdpi.com/2673-1924/4/1/2/pdf
Film on our "Reefs of Hope" coral restoration for climate change adaptation
strategies:  https://www.youtube.com/watch?v=BG0lqKciXAA
https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
<https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/>








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On Tue, Jul 25, 2023 at 3:11 AM Steve Mussman via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

>
> Hi Mel,
>
> I don’t know how there could be any science-based evidence that
> disinfecting scuba equipment is slowing or preventing the spread of SCTLD
> especially considering the fact that the specific pathogen involved has yet
> to be identified. However, my critique of the protocols affecting divers is
> also not founded on science. Mine is just a visceral reaction based solely
> on how I see divers interacting with infected corals and observations
> involving how the disinfection protocols are carried out in situ. There are
> just too many variables involved for this process to inspire confidence.
> While there is little known about the potential for scuba divers to serve
> as vectors of coral disease, there are a number of studies like this one:
> “Considering Commercial Vessels as Potential Vectors of Stony Coral Tissue
> Disease”
> https://www.frontiersin.org/articles/10.3389/fmars.2021.709764/full.
>
> Simply put, we don’t know how this disease is spreading, but I would
> assert that we do know that it is at least reasonable to assume that ships
> are potential vectors - therefore why all the focus on divers (an untested
> entity) while cruise ships arriving from other known-to-be-infected islands
> are continuing to be allowed to tie up close to shore virtually on top of
> some of Bonaire’s shallow reefs close to where the disease was first
> detected?
>
> Regards,
>
> Steve
>
> Sent from EarthLink Mobile mail
>
> On 7/23/23, 9:30 PM, Melbourne Briscoe <mel at briscoe.com> wrote:
>
> There is a lot of discussion on the Bonaire forum of ScubaBroad about the
> presumed futility of restricting divers in order to slow the progressions
> of SCTLD there. Is there any evidence that this is actually helpful, or is
> it simply a precautionary approach based on hope?
>
> - Mel Briscoe
>
> On Sun, Jul 23, 2023 at 7:55 PM Steve Mussman via Coral-List <
> coral-list at coral.aoml.noaa.gov (mailto:coral-list at coral.aoml.noaa.gov)>
> wrote:
>
> I have several recent photos of SCTLD infected corals from the reefs of
> Bonaire if anyone is interested, they are available to share.
>
> I also came across several pillar coral colonies that I’ve been informally
> monitoring over the years that have seemingly withstood multiple stressors
> including (so far) SCTLD. I’ve read that Dendrogyra cylindrus have been
> almost totally wiped out by SCTLD in Florida waters so I am wondering why
> they don’t suffer a similar fate on Bonaire. I’m guessing it has something
> to do with the fact that Bonaire’s waters have not yet warmed like
> Florida’s have. ( I have several pictures of what appear to be healthy
> pillar coral from Bonaire as well).
>
> Considering that paper on SCTLD and butterflyfish - what about other
> species as potential vectors? I have a good shot of a lizardfish laying
> directly upon a healthy star coral. It seems that there are multitudes of
> possible suspects. Although I faithfully disinfected my scuba gear as
> directed, I couldn’t help but feel like I was participating in a modern day
> version of a rain dance ritual.
>
> On a more positive note, a welcomed respite, there were no cruise ships
> barging in on Bonaire the entire week.
>
> Regards,
>
> Steve Mussman
>
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