[Coral-List] Cuba Coral Report and Evaluating the Recent Severe Bleaching on Caribbean Corals

Tue Jan 2 19:26:30 UTC 2024

Dear Vassil, Happy New Year!

Wonderful that the Coral Reefs of Cuba volume has been published.  Sadly,
unless the information was updated before publication, the work may now
represent a eulogy and window into the past, an important baseline with
which scientific evaluations of the recent climate disaster that hit the
Caribbean/Atlantic region can be made.

As you know, what just happened was unprecedented and shocking, it was the
most severe heat stress ever recorded in Cuba's history, fully double that
of any previous event.
https://coralreefwatch.noaa.gov/data/vs/ts_figures/ts_multi_year/vs_ts_multiyr_northwestern_cuba.png

This marine heat wave had degree heating weeks double of any past stress
events, with 24 DHW for SW Cuba, and 21 DWH for NW, SE, and NE Cuba.
https://coralreefwatch.noaa.gov/product/vs/timeseries/caribbean.php#northwestern_cuba

And the bleaching stress was everywhere, with most stations around the
region experienced extreme levels of 20-21 DHW.  Several stations stand out
as being even worse: the Florida Keys experienced 23 DHW, Jamaica, Southern
Hispaniola, and Bonaire, experienced 24 DHW, Columbia and Venezuela
experienced 25 DHW, Yucatan experienced 26 DHW, and Nicaragua suffered
through 27 DHW.

While I have no data on the specific impacts of this intense level of heat
to the corals, I do have experience working in the formerly most impacted
coral reefs of the planet, Kiritimati Atoll (Christmas Atoll), Kiribati, in
the Northern Line Islands. The 2015-16 bleaching event there had comparable
levels of stress to what Nicaragua just experienced, with 27 DHW.  I can
say with a fair degree of confidence that what just happened was likely an
extinction level event for many coral species. For the reefs which fared
slightly better, the few corals that remain will most be ecologically and
reproductively extinct, being so widely spaced that sexual reproduction is
no longer possible.  Of course there will be exceptions, and I hear some
positive news from Andrew Ross in Jamaica- of isolated A. palmata colonies
that did not even bleach.  But are these amazingly resistant corals now
being attacked by coral predators, as the predator to prey ratio might be
so badly skewed?  The most positive news I have heard thus far is from Lisa
Carne of Fragments of Hope in Belize, where in spite of widespread coral
death, many corals still remain attributed in part due to the focus on
incorporating as much genetic diversity as possible within the restoration
sites, which included the translocation of corals from warmer areas to
cooler areas.

While all is not lost, an urgent regional evaluation is certainly in
order.  But is that happening or is it planned?  Can those who work in each
of these areas openly share impacts and at least give impressions and first
assessments and any lessons learned?  This is of extreme importance,
because it has relevance to the survival of coral reefs all over the
planet.  What will the Caribbean be facing next summer?  What will it be
facing in the next decade?   And it is now the Southern Hemisphere's turn:
the heat is building in the South Pacific and Indian Oceans, and Kiribati
has already suffered yet another blow, while Tuvalu is now at record heat
stress levels expected to hold until May, as the marine heat wave deepens
and spreads regionally.  We need to work together!

Our reality has changed:  will we now experience bleaching conditions on
most reefs every summer from this point on?  The mean ocean temperature is
still holding at 5 standard deviations above the mean.
https://climatereanalyzer.org/clim/sst_daily/    1.5C has clearly been
surpassed and there is no going back.  With this new thermal reality, we
are quickly fast-forwarding to the future, and so it is now vital to figure
out our best options for preventing coral species from becoming extinct
locally and regionally.  Certainly the old models of coral reef restoration
must be changed?  I think that the best we can hope for now is to buy time
for each coral species.  Time for facilitated adaptation and endangered
species conservation rather than the former more random restoration
approach?  And what about coral nurseries, should we design them to
incorporate shading, for when it is required to prevent bleaching in the
nursery sites?

While I agree that we must keep the pressure on governments to reduce
fossil fuel use- any positve impact will take decades and so it will be too
late for coral reefs!   Right now, in the shadow of COP28, we must realize
that the chances of agreeing to phase out fossil fuels are less likely than
a nuclear war, less likely than AMOC collapse, or less likely than a
Carrington level solar event!   Time has run out.  Putting corals into
on-shore biobanks may seem the best way to go, and the heroic efforts of
those in Florida to carry that out coral rescue this past summer as an
emergency action saved much, but will then now go into the same stressed
areas?  For those proposing coral biobanks and onshore facilities, we
should not forget the tens of thousands of species that are associated with
coral reefs.  It is not just the corals that need to survive, it is the
bacteria, fungi, cryptofauna, etc, so our best bet over the long term is to
keep patches of coral reefs alive and in the ocean, and each coral species
in a reproductive condition for as long as possible.  This may not be
possible or practical for some areas or for some coral species, but
certainly Cuba and Belize and any coral reef area with a wide shelf and
strong thermal gradients has good potential for finding heat-adapted corals
and sweet spots where waters will remain cool enough for these most
bleaching resistant corals to survive over the next decade or so. Can we
begin gathering together and propagating some of what has survived to
secure it from preators, and to use these corals subsequently to create
patches of reproductive corals on the most promising reef areas we can
find?   What else night be possible?

Thanks to all who have worked so hard against all odds to keep coral reefs
alive.  And my sincere condolences to all those among our corla reef
communitiy who have suffered great loss this past year.  There are no
failures, there are only lessons learned.  We must succeed!

Regards,

Austin

Austin Bowden-Kerby, PhD
Corals for Conservation

https://www.corals4conservation.org
Publication on C4C's coral-focused climate change adaptation strategies:
https://www.mdpi.com/2673-1924/4/1/2/pdf
Film on our "Reefs of Hope" coral restoration for climate change adaptation
strategies:  https://www.youtube.com/watch?v=BG0lqKciXAA
https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
<https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/>

On Wed, Jan 3, 2024 at 3:31 AM Vassil Zlatarski via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Happy 2024 with the news for the just published *Coral Reefs of Cuba*, vol.
> 18 of the Series *Coral Reefs of the World*.
>
> Please let me know should you have any questions.
>
> Cheers,
>
> Vassil
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