[Coral-List] The Spread of SCTLD

Mon May 29 23:12:43 UTC 2023

     The US now has laws that require ballast water to have lower than a
certain number of organisms in certain small size ranges.  So the US does
have regulations, science-based, to try to limit species introduced via
ballast water.  Wikipedia has an article on it
https://en.wikipedia.org/wiki/Ballast_water_regulation_in_the_United_States
It says "Ballast water discharges are believed to be the leading
source of invasive
species <https://en.wikipedia.org/wiki/Invasive_species> in U.S. marine
waters, thus posing public health <https://en.wikipedia.org/wiki/Health> and
environmental risks, as well as significant economic cost to industries
such as water and power utilities, commercial
<https://en.wikipedia.org/wiki/Commercial_fishing> and recreational
fisheries <https://en.wikipedia.org/wiki/Recreational_fishing>, agriculture
<https://en.wikipedia.org/wiki/Agriculture>, and tourism
<https://en.wikipedia.org/wiki/Tourism>.[1]
<https://en.wikipedia.org/wiki/Ballast_water_regulation_in_the_United_States#cite_note-1>
Studies
suggest that the economic cost just from introduction of pest mollusks
<https://en.wikipedia.org/wiki/Mollusca> (zebra mussels
<https://en.wikipedia.org/wiki/Zebra_mussel>, the Asian clam
<https://en.wikipedia.org/wiki/Corbicula_fluminea>, and others) to U.S.
aquatic ecosystems is more than $6 billion per year."

There is also an International Convention (treaty) on ballast water.
Wikipedia has a page on it
https://en.wikipedia.org/wiki/Ballast_Water_Management_Convention
Wikipedia says "As of 15 July 2021, 86 countries were contracting States to
the BWM Convention (representing 91.12% of the gross tonnage of the global
merchant fleet)"  (to my complete surprise, leadng "flags of convenience
countries have signed it).  There are several "flags of convenience"
countries like Liberia and Panama where shipping companies commonly
register their ships, because they have lower standards for safety (and
safety standards cost shipping companies money) and/or cheaper fees for
registering their ships and/or less enforcement of their regulations,
and/or lower minimum wages, etc.)  I notice the Wikipedia article does not
talk about enforcement.  Regulations that are not enforced don't mean
much.  The standards include that ballast water exchanges must be carried
out at least 200 nautical miles from shore.  I thought I saw in Wikipedia
that a typical cost of a system to sterilize ballast water up to the
standard is about $5 million.  Enforcement of ballast water laws may be
largely done at ports of call, where ballast water can be tested for the
abundance of plankton and bacteria, etc.  Some countries may enforce it
more rigorously than others.  They might check ship logs to see whether
ballast exchanges are far enough from shore.  I'm guessing on this, I
didn't see it mentioned in the articles, but I haven't read all the details
in the articles.

You guessed it, Wikipedia has an article on "Flags of Convenience"
https://en.wikipedia.org/wiki/Flag_of_convenience
It reports that Panama, Liberia, Marshall Islands, Singapore, and Hong Kong
have the most ships registered among flags of convenience.  Flags of
Convenience are also used to hide the identity of ship owners, avoid taxes,
pay low wages, and engage in a variety of illegal activities, including
illegal fishing.  I could find no statement of whether Flag of Convenience
nations have less enforcement of ballast regulations, but I suspect that
enforcement may be more likely as ships go in and out of ports of countries
that do enforce such regulations.  But enforcement would surely be a
critical step.

        In Steve's defense, I would point out that a correlation between
the frequency of diving in an area and the amount of coral disease is just
that, a correlation, and we know that correlation does not prove
causation.  Places that have huge amounts of diving also are highly likely
to have other major damaging effects of development and human population,
such as sewage discharges, etc, as Mark has pointed out.  That makes a
difference, since if that's the cause of the disease increase, then it is
not just the diving that causes it, and it is likely that better
organization and investment and laws and enforcement to reduce those
impacts could reduce the amount of disease produced.  Granted, low-income
countries have limited abilities to scramble quickly and do those things
when there is a sudden major increase in dive tourism in a specific area
and there is sudden large local development.  And there are three major
aspects of disease, once called the "Coral Disease Triangle", the host, the
pathogen, and the environment.  Anything that weakens the coral is likely
to weaken their defense against disease, and some things (like traces of
iron) can increase diseases without having to provide any pathogens.
Anything that causes a rapid and very large increase in the local human
population could cause an increase in diseases by such mechanisms and on
the other hand, controlling those things could mitigate effects on the
reefs such as those Mark outlined for us.

Cheers,  Doug

Bruno, J. F. 2015. The coral disease triangle. *Nature Climate Change* 5:
302-305.

On Mon, May 29, 2023 at 9:57 AM Steve Mussman via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

>
> I would like to offer a partial retraction to some of the previous
> comments I made relating to the potential for recreational scuba divers to
> be vectors for SCTLD.
>
> Thanks go out to Doug Fenner for providing me with a number of scholarly
> papers (below) linking recreational scuba divers to reef damage and the
> prevalence of coral diseases. In light of these findings one could conclude
> that it is reasonable and perhaps even prudent to consider implementing
> some level of restrictions on divers in an attempt to limit the spread of
> (some) coral diseases. However, I would also point out that there are even
> a greater number of credible scientific papers on the potential for bilge
> and ballast water from boats and ships to serve similarly as coral disease
> vectors - but as far as I know, no limitations or restrictions are being
> put in place to limit the potential impacts from these alternate sources.
>
> This further bleeds over into a related discussion on the fallacies
> underlying the concept of “sustainable tourism”. I would simply assert that
> the failures attributed to “sustainable dive tourism” are actually the
> result of the fact that the current level of regulations commonly
> implemented do not rise to the level necessary to actually provide
> protection for coral reefs. I can envision “true sustainable dive tourism”,
> but the bottom line is that the dive tourism industry (in its current
> manifestation) is highly unlikely to voluntarily agree to implement and
> adhere to the standards that would be necessary to truly change the
> paradigm.
>
> Scuba diving damage and intensity of tourist activities increases coral
> disease prevalence.
> https://www.sciencedirect.com/science/article/abs/pii/S0006320714002730?via%3Dihub#preview-section-abstract
>
> Close encounters of the worst kind: reforms needed to curb coral reef
> damage by recreational divers.
> https://link.springer.com/article/10.1007/s00338-021-02153-3
>
> Recreational Diving Impacts on Coral Reefs and the Adoption of
> Environmentally Responsible Practices within the SCUBA Diving Industry.
> https://link.springer.com/article/10.1007/s00267-016-0696-0
>
> Using Coral Disease Prevalence to Assess the Effects of Concentrating
> Tourism Activities on Offshore Reefs in a Tropical Marine Park.
> https://conbio.onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2011.01724.x
>
> Regards,
>
> Steve Mussman
>
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