[Coral-List] SCTLD in ballast water

[Steve Mussman]

I don’t believe anyone is claiming to have definitive proof that the pathogen associated with SCTLD is being spread directly by ballast water, although there appears to be solid justification for further research into that particular hypothesis and it is most certainly not based on political correctness. John Bruno recently made a compelling argument (as many others have) that climate change, although not suspected of being the primary cause of coral diseases, is also involved. “Higher than normal temperatures are thought to increase the occurrence and severity of disease outbreaks through several mechanisms, including increased pathogen virulence and weakened host immune systems owing to physiological stresses.” In his paper “The Coral Disease Triangle”, John makes note of the fact that it is still the subject of speculation that the unknown pathogenic bacterium associated with white-band disease may have been introduced into affected regions “perhaps via the Panama Canal or in ballast water carried by cargo ships”. Although a water-borne pathogen could be spread by currents alone, ballast water from ships might explain how it has spread to geographically and oceanographically isolated reefs.

https://www.researchgate.net/publication/274312564_The_coral_disease_triangle

Regards,

Steve

On 7/30/22, 3:46 PM, Eugene Shinn via Coral-List <coral-list at coral.aoml.noaa.gov> wrote:

I scanned the interesting research paper that blames coral disease is

spread by ships ballast water. It is a reasonable hypothesis. However, I

agree with Alina Szmant. I too have not seen the proof. She pointed out

that the paper was not peer reviewed. The first thing I noticed in the

papers title were the words, “simulated ballast water.” If I were a

shipping company owner and that study was being used as proof my ballast

water was the major spreader and cause of coral reef demise I would

surely have my high paid lawyers go on the attack. They could quickly

point out that the study of simulated ballast water does not prove my

ballast water causes disease. That otherwise excellent study made me

wonder why did the authors not sample water from actual ship ballast

tanks? Why use simulated ballast water? At the same time I have to agree

there is no evidence that real ballast water is not a carrier of coral

disease. Ballast water may actually be spreading coral toxins from reef

to reef. However, the real question is If there are disease organisms in

ballast water, where did they come from in the first place. Clearly once

these agents are in the water column they can easily be moved along with

water currents. They do need ballast water for transport. The major

current flow directions in the Caribbean are well known and the

strongest of these currents flow past the Belize and Florida Keys reefs.

As many list readers know I have been advocating since the 1980s that

disease agents in the Caribbean were originally brought to the western

Atlantic/Caribbean in dust clouds transported by the Tradewinds. Dust

particles carrying disease causing agents are constantly dropping out as

the dust clouds move along. Many even cross over into the Pacific. Once

corals and other organisms including /Diadema/ and Seafan diseases

become established they are easily transmitted down current to affect

other marine organisms. I have often suggested the demise of the

staghorn fields at San Salvador in 1983, was a starting point for such

transport.

Back when my USGS dust study team was active in the late 1990s they

cultured and identified around 200 microbes and fungi that were being

transmitted in African dust clouds. At the time we knew asthma was by

rampant in children on those windward islands in the Bahamas. Even

Puerto Rico is well known for its respiratory diseases. In those days it

baffled me why so many competent scientists rejected the dust

hypothesis. Later as I matured I realized it was all about politics and

funding. I suppose blaming coral diseases on ballast water these days is

politically correct. Gene

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