[Coral-List] Outbreaks of Coral Diseases: A Threat to Ocean Ecosystems

[Douglas Fenner]

       I agree with most of your statements.  Disease is clearly a major
threat, but in the Indo-Pacific, at least so far, it has done a lot less
damage than in the Caribbean and Florida.  It could be that the Caribbean
is a window into the future for the Indo-Pacific.  That's a scary thought
but quite possible.  The Indo-Pacific is just as subject to heat waves and
mass coral bleaching as the Caribbean and the Indian Ocean got hit harder
than the Caribbean in the big 1998 El Nino global mass coral bleaching
event.  Plus, high water temperatures facilitate outbreaks of some
diseases.  However, the Indo-Pacific has been more resilient than the
Caribbean and Florida (Roff and Mumby, 2012).  We should always distinguish
what has happened in the past from what the future threats are because the
threats are increasing with time, and which threats will be the worst in
the future may not be the same as in the past.  So the Indo-Pacific may be
hit very hard in the future by coral disease, only time will tell, and we
had better be ready in case it is.
      Not all diseases are caused by biological pathogens like microbes and
parasites.  Some are not infectious.  In humans, diabetes is increasing but
not infectious, most cancers are not infectious, or heart disease, and
there are many others.  A narrow but popular definition of disease is that
it consists of infectious diseases, but a broader definition is anything
that reduces health, which includes metabolic diseases, genetic diseases,
physical injury, poisoning, maybe old age (medical specialty gerontology),
and many others.  Mass coral bleaching can be considered a stress response
and a physiological disease like heat stroke and heat exhaustion in
humans.  ALL organisms have maximum temperatures they can survive (Fenner,
2023).
       Diseases in corals are not trivially easy to treat or combat and for
many diseases the causes have been very hard to find.  Reducing other
stresses may help, but we're already trying to do that and it will not be
easy to suddenly do a great job reducing other stresses when we've been
trying to do that (rather unsuccessfully) for decades.  World society has
not been willing to dedicate the resources needed to combat the human
causes of reef decline, most reefs are in countries that do not have the
resources to do it, and developed countries have lots of other higher
priorities.  I'd argue that although coral reefs would surely be in worse
condition if we hadn't been working hard to reduce impacts, on the whole,
we have been losing for decades because the situation for reefs has gotten
worse and worse, and at present the predictions for the future are much
worse than the condition they are in are now.  I'd also argue that an
examination of the actual existing graphs of coral cover over time does not
support the widespread notion that we have lost most of the corals
worldwide (though they have been lost in the Caribbean and Florida, and in
some other specific spots).  Obviously there have been mass mortalities and
a myriad of damaging effects on reefs, but particularly in the
Indo-Pacific, many times (but NOT all!), reefs have bounced back.  They
will NOT be able to continue to do that forever.  And, increasing coral
diseases are a big future threat, if Caribbean diseases like Stony Coral
Tissue Loss Disease (SCTLD) get into the Indo-Pacific, the result could be
a disease catastrophe there as bad as in the Caribbean.  And it is quite
possible that ship ballast water could do that any day.
      So your concerns are NOT misplaced at all, they are spot on.

Cheers, Doug

Roff, G. and Mumby, P. J. 2012.  Global disparity in the resilience of
coral reefs. Trends in Ecology and Evolution 27 (7): 404-413.

Fenner, D. 2023.  Corals of Hawaii, 2nd edition.  Mutual Publishing and
Maui Ocean Center.  440pp.

On Sun, Jan 14, 2024 at 10:11 AM Canoracox via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Coral reefs are among the most diverse and rich ecosystems on the planet.
> They provide habitat for numerous marine species and play a crucial role in
> maintaining the health of the oceans. However, in recent decades, coral
> reefs have been facing constant threats, including the outbreak of coral
> diseases. These diseases have had a significant impact on the overall
> health and survival of coral reefs worldwide.
>
> Understanding Coral Diseases:
> Coral diseases are caused by a variety of factors, including bacterial,
> viral, and fungal pathogens. They can affect both hard and soft corals,
> leading to tissue damage, discoloration, and ultimately, death. Coral
> diseases can spread rapidly within a reef system, causing mass mortality
> events and devastating entire coral communities.
>
> Factors Contributing to Outbreaks:
> Several factors contribute to the outbreaks of coral diseases.
> Environmental stressors such as rising sea temperatures, pollution, and
> coastal development weaken the immune systems of corals, making them more
> susceptible to infections. Additionally, human activities like overfishing
> and destructive fishing practices can disrupt the delicate balance of reef
> ecosystems, further exacerbating the spread of diseases.
>
> Global Impact:
> The global impact of coral diseases cannot be underestimated. Coral reefs
> are not only vital for biodiversity conservation but also provide numerous
> ecosystem services, including coastal protection, tourism, and fisheries.
> When coral reefs are affected by disease outbreaks, these services are
> compromised, leading to economic losses and ecological imbalances.
> Moreover, the loss of coral reefs has cascading effects on other marine
> organisms that depend on them for food and shelter.
>
> Efforts in Disease Management:
> Efficient management and mitigation strategies are crucial in addressing
> coral disease outbreaks. Early detection and monitoring systems can help
> identify disease hotspots and allow for immediate action. Implementing
> measures to reduce stressors, such as improving water quality and
> implementing sustainable fishing practices, can enhance the resilience of
> coral reefs and reduce disease susceptibility. Furthermore, promoting
> public awareness and engagement in coral reef conservation can contribute
> to long-term solutions.
>
> [Conclusion](
> https://outbreaksofcoraldiseases.blogspot.com/2024/01/outbreaks-of-coral-diseases-threat-to.html):The
> outbreaks of coral diseases pose a significant threat to the health and
> survival of coral reefs worldwide. Understanding the causes and impacts of
> these diseases is vital for developing effective management strategies. It
> is imperative that governments, organizations, and individuals collaborate
> to protect and restore coral reef ecosystems, ensuring their resilience in
> the face of disease outbreaks and other environmental challenges. Only
> through concerted efforts can we safeguard these invaluable ecosystems for
> future generations.
>
> Отправлено с помощью защищённой почты [Proton Mail](https://proton.me/).
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