[Coral-List] The Spread of SCTLD

[Steve Mussman]

“It is unclear why it is surmised that divers cannot spread SCTLD. I don't believe anyone has suggested that divers are the sole vector, so it is a bit of a strawman argument to say that they cannot be one of the possible vectors”.

Dear Mel,

As Bill just mentioned, hypothetically, divers could be a possible vector, but I asked if there was any compelling science-based evidence to support that assumption. There seems to be an abundance of studies already published regarding biofouling and ballast water (as potential vectors), but I simply can’t find any science that would lead me to conclude that divers are likely to be carrying and/or transmitting coral diseases. Correlation is one thing, but it seems to me that it would not be overly burdensome to test the divers as vectors hypothesis before imposing arbitrary restrictions. Meanwhile I’ll gladly disinfect my gear and stay out of restricted areas, but I’d do it with more enthusiasm if some of the other conceivable vectors you mentioned were subjected to equitable scrutiny. All this makes me wonder if science is guiding the response or are divers just providing the lowest hanging fruit.

Regards,

Steve Mussman

Sent from EarthLink Mobile mail

On 5/24/23, 9:44 PM, Melbourne Briscoe <mel at briscoe.com> wrote:

It is unclear why it is surmised that divers cannot spread SCTLD. I don't believe anyone has suggested that divers are the sole vector, so it is a bit of a strawman argument to say that they cannot be one of the possible vectors.

The arrival of SCTLD on Grand Cayman is a bit of a mystery, since it was not observed (to my knowledge) at the shipping/cruising dock sites until long after it had propagated around the island. How did it do that?

One should allow for multiple vectors of varying strength: cargo ships, cruise ships, currents, fish, divers, dive boats, pleasure boats. It is easy to hypothesize that cruise ships carry the disease to an island, and then currents, fish, and divers take over. But that can be tested.... The cargo and cruise ships would not seem to be the main vector in the Florida reef tract or Grand Cayman, no matter how much you dislike those ships.

I do not have the data to attempt a multi-vector analysis; does anyone?

- Mel

On Wed, May 24, 2023 at 7:30 PM Todd Barber via Coral-List <coral-list at coral.aoml.noaa.gov (mailto:coral-list at coral.aoml.noaa.gov)> wrote:

Steve,

You are correct and it's a keen observation, in fact, a very reasonable

hypothesis is that STCLD is found more at dive sites than non-dived sites

because Scuba Divers are a defacto undersea monitoring system. People

report reefs dying so we are alerted first in areas where people dive.

Either way, this is a scientific list so let's try to keep the topics as

factually based as we can.

Thanks,

Todd R Barber

Chairman, Reef Ball Foundation

712 Portia Street North, Nokomis, FL 34275

941-720-7549 (Cell & Google Voice)

www.reefballfoundation.org (http://www.reefballfoundation.org/)

www.reefbeach.com (http://www.reefbeach.com/) (Reefs for Beach Erosion)

Reef Ball World Mapping System

<https://www.google.com/maps/d/edit?mid=1KrENaH-kJn_LCDrzCbgtW_1aW-ciY-M&usp=sharing>

On Wed, May 24, 2023 at 2:46 PM Steve Mussman via Coral-List <

coral-list at coral.aoml.noaa.gov (mailto:coral-list at coral.aoml.noaa.gov)> wrote:

>

>

> Dear Rupert,

>

> I still have not been able to find any studies (beyond the questionable

> one I mentioned earlier) that substantiate the concept of divers as vectors

> of coral disease. I’m not attempting to defend the diving industry’s

> environmental impacts or policies as I’ve been an outspoken critic of their

> lack of leadership on these issues for years. But in this case, divers are

> being singled out while what seem to be more obvious, potential spreaders

> are given a pass. Consider the fact that in Cozumel, Mexico SCTLD was first

> identified on Paradise Reef, an area where cruise ships (and cargo ships)

> dock daily. Same holds true for where the disease was first found more

> recently on Bonaire. As for Grand Cayman, I just received information

> indicating that SCTLD has been found on sites generally inaccessible to

> divers. By the same token, I was told that the disease has not yet found

> its way to Cayman Brac and Little Cayman, smaller, sister islands that are

> popular dive spots, but never visited by cruise ships. In light of these

> revelations it seems like a knee-jerk reaction to place restrictions on

> divers. Beyond that, these policies serve to strongly suggest that divers

> are the primary vectors all the while conveniently deflecting attention

> away from other, perhaps more “inconvenient” potential spreaders of coral

> disease.

>

> Regards,

>

> Steve Mussman

>

> Sent from EarthLink Mobile mail

>

> On 5/22/23, 9:25 AM, Rupert Ormond via Coral-List <

> coral-list at coral.aoml.noaa.gov (mailto:coral-list at coral.aoml.noaa.gov)> wrote:

>

> Steve,

>

> My understanding is that there is quite good evidence from the Cayman

>

> Islands that SCTLD is being spread by divers and / or diveboats (in

>

> ballast tanks?). I believe the main evidence is that they are mainly

>

> finding SCTLD at dive sites (which are designated with mooring buoys

>

> etc.) but not or very little on the stretches of reef in between where

>

> diving is not permitted.

>

> I believe a report on this is due, but at this stage you should probably

>

> contact the Dept of Environment there for more information, if required.

>

> sincerely,

>

> Rupert

>

> Rupert Ormond

>

> Co-Director, Marine Conservation International

>

> Hon. Professor, Centre for Marine Biodiversity & Biotechnology,

>

> Heriot-Watt University, Edinburgh

>

> Editor REEF ENCOUNTER (news journal of the International Coral Reef

> Society)

>

> On 27/04/2023 13:09, Steve via Coral-List wrote:

>

> > Recent developments related to the spread of SCTLD throughout the

> Caribbean have resulted in a number of dive destinations placing

> restrictions on scuba divers in an attempt to contain the spread of the

> disease. While some locations have taken an approach requiring disinfection

> of equipment as well limitations on specific dive sites, others have

> imposed no restrictions at all. From everything I can gather, SCTLD is

> known to be water-borne and fast spreading and likely bacterial. All of

> which raises a few questions for the coral disease experts here.

>

> >

>

> > Does anyone know of any study that actually concluded that divers/diving

> equipment (used under normal circumstances) can carry and or transmit coral

> disease pathogens? Put another way, Is there actual hard evidence of divers

> as vectors of this or any other coral disease?

>

> >

>

> > I did find evidence of one study that showed that wetsuit material can

> hold and transfer bacteria, but it was a lab experiment and did not seem to

> me to replicate what occurs in situ.

>

> >

>

> > And what about marine life? Theoretically, could a bacterial pathogen be

> carried about by turtles, rays, crustaceans and such?

>

> >

>

> > Thanks in advance for your help.

>

> >

>

> > Regards,

>

> >

>

> > Steve Mussman

>

> >

>

> > Sent from EarthLink Mobile mail

>

> >

>

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>

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