A disease is wiping out Caribbean corals. Coming soon to a reef tank near you?

[AquaBiomics]

Some of you may have read about a disease that is devastating coral populations throughout the Caribbean. As if these populations hadn't already been through enough, between runoff, overfishing, and warming -- now they're facing yet another disease outbreak.

The following image, from a publicly available article at www.secore.org, illustrates the symptoms of this disease.


Researchers are calling this Stony Coral Tissue Loss Disease, or SCTLD. There is an excellent description in this article on Science News. I'd urge you to pay attention to the language these researchers are using. One of the leading scientists studying this disease, Dr. Marilyn Brandt, describes it this way:

It marches along the reef and rarely leaves corals behind... we’re pretty scared.

A recent study using DNA sequencing identified five bacteria associated with this disease. You can read more in this open-access article (I warn the reader, this is a technical article and its pretty dense). The researchers stop short of calling these pathogens, since some of the requirements for formally making this designation have not been established. But the evidence in this study is pretty compelling, and several of these same bacteria have previously associated with coral disease.

Here's an image from the publicly available article, showing symptoms of the disease from this study

The five bacteria identified in this study were present in many or all of the diseased tissues and absent in most or all of the healthy tissue samples. (Further details are available in the article). These are really strong associations -- you could reliably determine whether a sample came from diseased or healthy tissue based entirely on the presence of these bacteria.

Since the researchers used exactly the same genetic marker for this study that I do for AquaBiomics testing of home reef tanks, I couldn't resist asking: are any of these recently described bacteria present in our samples?

The answer is absolutely yes -- I've found perfect, 100% matches to four of these SCTLD-associated bacteria in samples from a small number of home reef tanks. Each of these likely pathogens was found in about 2 to 14% of tanks. Some tanks had more than one. This figure shows the percentages of each type in the tanks I've sampled so far (79 different tanks are included in this dataset).

I will be working to further document effects of these likely pathogens, since I have access to some tanks containing one or more of these. And I'll be contacting the owners of these tanks to let them know!

For now, I wouldn't draw any conclusions beyond what the researchers who wrote the study have claimed. They said,

A single potential pathogen was not identified; however, five unique ASV sequences were enriched in the SCTLD lesions of M. cavernosa, D. labyrinthiformis, and D. stokesii, and all but one of these sequences were exact matches to sequences previously associated with coral disease.

They also caution that

The enrichment of disease-associated bacteria in the lesions of corals with SCTLD is not definitive proof that the pathogen is bacterial. However, disease progression in laboratory and field trials appears to slow or stop with the application of antibiotics, strongly suggesting that bacteria are involved with disease progression.

My contribution here is simply to bring your attention to these recently described bacteria of interest in the study of SCTLD, and to point out that exactly the same bacteria are starting to show up in home aquariums.

I will be looking into the information on those tanks to see what we can learn about the possible origins and effects of these bacteria in our tanks... for now, I'll take the researchers' conclusions at face value that these are prime candidates in the search for the cause of SCTLD. And probably not something I would like to have in my tank (so far, my home tanks appear free of most of them /knock on wood)

 

[Reefer5640]

Thanks for the heads up! How are you testing this? With a water sample or a tissue scrap from stony corals? Do you know if these tanks that you found these in were running decent UV sterilizers? Would you be interested in people sending you samples?

 

[saltyhog]

I don't think it's throughout the Caribbean ..at least not from the map in that article or my experience. It looks like it's most focused in Mexico. I wonder if it's the cause of the problems in Cozumel that caused them to shut down some of the marine park there!

I did not see any evidence of this issue in recent trips to St. Croix, Little Cayman, Grand Cayman recently. Small sample size though.

 

[lexinverts]

Eli just let me know that I have one of these bacteria (Vibrio sp.) in one of my frag tanks. He was able to detect it with the regular water sample and pipe swab protocol. I did recently lose a few acros in that tank. Yikes!

 

[AquaBiomics]

I don't think it's throughout the Caribbean ..at least not from the map in that article or my experience. It looks like it's most focused in Mexico. I wonder if it's the cause of the problems in Cozumel that caused them to shut down some of the marine park there!

I did not see any evidence of this issue in recent trips to St. Croix, Little Cayman, Grand Cayman recently. Small sample size though.

Thanks, this is a great point to clarify.

Each research article will tend to focus on an individual area. But the disease has been reported through Jamaica, Florida, the Flower Garden Banks, Mexican Caribbean, St. Maarten and, most recently St. Thomas, USVI and the Dominican Republic. Pretty widespread!

There is a great map at this site that tracks the recent spread of this disease. I note that the FGB report is not included on the map, but regardless, its at least a reasonably complete record

Coral Disease Outbreak - AGRRA

www.agrra.org

 

[AquaBiomics]

Eli just let me know that I have one of these bacteria (Vibrio sp.) in one of my frag tanks. He was able to detect it with the regular water sample and pipe swab protocol. I did recently lose a few acros in that tank. Yikes!

I seem to recall you mentioned seeing some tissue necrosis in Favia or some other LPS recently. Did those end up in this tank? I ask because many of the species affected by SCTLD in the Caribbean are LPS.

(Of course LPS vs SPS has no basis in phylogenetics, and this pattern could just be because there are so few Caribbean Acros in the first place, but in any case it makes me curious about LPS mortality).

 

[lexinverts]

I seem to recall you mentioned seeing some tissue necrosis in Favia or some other LPS recently. Did those end up in this tank? I ask because many of the species affected by SCTLD in the Caribbean are LPS.

(Of course LPS vs SPS has no basis in phylogenetics, and this pattern could just be because there are so few Caribbean Acros in the first place, but in any case it makes me curious about LPS mortality).

Yes, they did. But, they were moved from my Red Sea 750 tank, which you also tested recently. I guess it is possible that the infection moved completely with the corals and did not show up in the RS 750 tank...

 

[Steve Erekson]

I don't think it's throughout the Caribbean ..at least not from the map in that article or my experience. It looks like it's most focused in Mexico. I wonder if it's the cause of the problems in Cozumel that caused them to shut down some of the marine park there!

I did not see any evidence of this issue in recent trips to St. Croix, Little Cayman, Grand Cayman recently. Small sample size though.

I saw no problems in Belize in June last year. Might have been before this started though.

 

[AquaBiomics]

I saw no problems in Belize in June last year. Might have been before this started though.

I'm jealous of you guys' travels! I have to confess I have not been in the water anywhere in this region since the outbreak began, so I am reporting only based on what I'm reading. My understanding is that many areas have only begun to see the effects within the past year.

 

[AquaBiomics]

How are you testing this? With a water sample or a tissue scrap from stony corals? Do you know if these tanks that you found these in were running decent UV sterilizers?

The test uses DNA sequencing to target a genetic marker widely used for identifying Bacteria and Archaea. Most of my samples are water and biofilm samples from aquariums (and these bacteria are all more abundant in the water samples than in the biofilm, by far). I do have some coral mucus samples in the database too and none of the pathogens showed up in them (but also didnt show up in the water sample from that tank)

Interesting question about UV sterilizers, it's one of many factors I'll have to look at. most of the tanks in the database do not have UV sterilizers, but maybe enough to address this question.

 

[ostrow]

It definitely looked like those photos on many, many corals last year in Grand Cayman, and is rampaging through Turks and Caicos as of 8 weeks ago.

 

[Mgex]

Eli just let me know that I have one of these bacteria (Vibrio sp.) in one of my frag tanks. He was able to detect it with the regular water sample and pipe swab protocol. I did recently lose a few acros in that tank. Yikes!

Vibrio is the family of human flesh eating bacteria that is prevalent along the gulf coast it affects corals like that too ?

 

[lexinverts]

Vibrio is the family of human flesh eating bacteria that is prevalent along the gulf coast it affects corals like that too ?

Vibrio also causes disease in fish and corals. You can learn more about the different types of bacteria that we find in our tanks here:

www.aquabiomics.com

 

[Ophelia’s Reef]

“My contribution here is simply to bring your attention to these recently described bacteria of interest in the study of SCTLD, and to point out that exactly the same bacteria are starting to show up in home aquariums.”

Maybe it’s not that these bacteria are starting to show up....but they have always been there but are now being tested for. I suspect the bacteria are opportunistic rather than the primary or underlying trigger for SCTLD. Are you seeing evidence of SCTLD in the home aquariums you tested?

“Collectively, the presence of similar microbes in several coral diseases from around the world can be interpreted in multiple ways. These microbes may be the pathogens that initiate coral disease, however, their presence in multiple, visually distinct coral diseases suggests that this may not be the case. In addition to primary pathogens, these microbes may be opportunistic or secondary pathogens that infect immunocompromised or otherwise vulnerable corals (Lesser et al., 2007), such as those stressed by elevated water temperatures or sedimentation.”

 

[Back where it all began]

Could one assume that live rock from one of these areas with or without coral could be a transmission route?

 

[JoshF7]

Could one assume that live rock from one of these areas with or without coral could be a transmission route?

Having just recently received some from the Florida Keys area, I'm definitely interested in this question as well!

 

[KenO]

Eli tested my setup and I have the Vibro sp in my tanks. Tanks have been struggling, I lost every sps and most of my Duncan’s, hammers and torches. Lately it has been better. I just sent in a 2nd test to see if it has gotten any better or worse. I did start my tanks with a small amount of LR from Florida.

 

[amps]

I lost a ton of LPS and SPS 2 years ago to what I figured was an unknown disease. There didn't seem to be anything else remotely wrong parameters wise, no foreign contamination, no heavy metals and no swings in stability. At the same time, dozens of hobbiest in my area started to complain about dead torches and other LPS and SPS corals. In each case it looked like something had eaten the sensitive tissue where the flesh meets the skeleton.

I spoke to a frag vendor I know since he deals mostly in very high grade LPS and he told me that he started dosing Chemiclean after the first few incidents and the problem went away. Now he doses it prophylactically every 4-6 months or after a large import shipment. He hasn't lost any more corals while everyone around him is crashing.

I wonder if it was the disease from this article that made the rounds through our tanks and caused all this damage.

 

[NDIrish]

I'm definitely interested in this. I just ordered some Florida Keys sand and mud. Now it makes me wondering about using them or not take the chance and throw it out.
Eli, same sand and mud you referred to in a previous article to increase bacteria.

 

[drawman]

Following. I believe I remember hearing about this in the Virgin Islands last year. Very sad to see like you said corals don't need another hit.