[Coral-List] Responding to Coral Bleaching

Bill Allison allison.billiam at gmail.com
Tue Sep 22 10:39:39 EDT 2015

re. COTS outbreaks, damsels, and the wars on COTS

Hi Tim,
I did this on a small scale on a number of reefs in the Maldives.
Stegastes nigricans definitely successfully defends against COTS there (and
elsewhere as per the literature).
In the early 90's the only patches of live Acropora spp. after COTS
outbreaks on some reefs of North Male Atoll were inhabited by S. nigricans.
In lagoons these were patches of branching acropora surrounded by dead
acropora. On rubble beds, and on jettys and breakwalls made of mined
corals, I found live acropora of various forms only within areas inhabited
and defended by S. nigricans.
I observed S. nigricans attacking COTS and driving them away and when I
placed COTS within territories they were driven away.
During a subsequent outbreak a few years later with acropora and
pocillopora very scarce, colonies at the periphery of S. nigricans
territories had only branches distal to the territory centre killed.

Areas defended by S. nigricans may function as refuges seeding subsequent
recovery, but encouraging S. nigricans to control COTS* would, like many
proposed actions, merely be another band-aid or worse, (like the war on...
fill in the blank), diverting attention and resources from discovering and
addressing fundamental causes of a complex problem.
In the case of COTS, eutrophication and COTS predator removal are likely
two contributing factors.


*I know you are not proposing this Tim but there are plenty of wannabe
warriors out there.

On Mon, Sep 21, 2015 at 8:56 AM, Tim <tim at atolleditions.com.au> wrote:

> Hi Austin,
> There are around four Stegastes damselfish in the Maldives, of which two
> species Stegastes nigricans and Stegastes lividus – both widespread
> Indo-Pacific species – appear to be the most common.
> I'm not sure how many species occur elsewhere, or their abundance, but if
> I had to choose representative species to monitor across the entire
> Indo-Pacific, it would be these two. Would you agree?
> What about the other farmer damsels, the Plectroglyphidodon?
> Plectroglyphidodon lacrymatus and Plectroglyphidodon dickii are two of the
> five common Maldives, widespread Indo-Pacific species. From your
> experience, are these as equally aggressive in attacking COTS?
> Is there any benefit to be gained by widespread Indo-Pacific monitoring of
> representative fish species, such as the Stegastes, as a comparative COTS
> study before, during and after outbreaks?
> I ask this because if controlling COTS outbreaks means involving the wider
> community for assistance, involvement can be made more enticing by
> providing interesting and stimulating engagement in monitoring activities..
> I also adhere to the KISS principle, Keep it Simple Sid (as well as Keep
> it Sexy Sid!)
> Regards
> Tim Godfrey
> Atoll Editions
> www.atolleditions.com.au
> www.fishesofthemaldives.com
>  that are absolutely essential in the post-bleaching survival of
> > corals
> On 19 Sep 2015, at 18:12, Austin Bowden-Kerby wrote:
> > Bula Dennis and others on the list,
> >
> > Interesting observations, many of which have good merit.  However, I find
> > that a paralysis of will can sometimes be the result of too much side
> > thinking and doubting.  This massive bleaching will come and then it will
> > go very quickly, and it may not return for five years or a decade or so,
> so
> > study it now or perhaps lose the chance- none of us are getting any
> > younger!
> >
> > The point I have tried to make is that we have an urgent situation at
> hand
> > that threatens coral reefs NOW.  If this were a climate change event
> > occurring ten thousand years ago when human impacts were insignificant,
> > coral reefs would be ecologically balanced and certainly better capable
> of
> > adapting.  But from what I have experienced, every reef is more or less
> > under some sort of human-induced stress that makes adaptation to climate
> > change much more difficult.  I am proposing a completely new strategy
> that
> > gives people something to actually do about bleaching over the short
> term.
> > I have seen that it can make a very big difference.
> >
> > Most of the adaptive potential of coral species to beaching rests with
> the
> > bleaching resistant coral colonies, but adaptation is for the most part
> > (based on my own experience), being prevented by over-abundance of coral
> > predators on reefs, which so often kill most of the surviving corals.
> This
> > is a testable hypothesis that could be an important part of the salvation
> > of coral reefs.  Predator removal during and after bleaching also gives
> > conservationists and activists something to do to fight back, rather than
> > sitting on their butts and becoming depressed because there is nothing
> they
> > can do.  People desperately need hope at this time, otherwise they may
> just
> > give up on coral reefs.
> >
> > I am simply suggesting that for those who live near coral reefs, that
> they
> > might focus on what happens subsequently to a massive die off of
> > susceptible corals, knowing that the surviving resilient corals must
> > survive in order for the coral reefs to adapt to the new stressors.
> > Wherever 80-95% of the corals end up dead, high background numbers of
> > and snails etc. seem to prevail nearly everywhere, and these predators
> have
> > the potential to kill everything (palatable) that survives the bleaching.
> > Ironically for Pacific reefs, in my experience, it is the Stegastes
> > damselfish that are absolutely essential in the post-bleaching survival
> of
> > corals- on many reefs their territories are the ONLY place where any
> > Acropora or Pocillopora will escape the COTS.  They actively attack the
> > COTS and drive them away, as if the COTS were invading sea urchins trying
> > to steal their algae.  Another easily tested hypothesis, although there
> is
> > an older paper documenting this behavior from Pacific Panama.
> >
> > In the Caribbean, I have found that snails and fire worms rarely kill an
> > entire colony, and when they do it may take weeks for them to finish the
> > job.  However, in the Pacific, a single COTS will kill a fist-sized or
> > plate-sized piece of coral every day/night, and will normally kill entire
> > colonies before moving on. They can also form fronts and kill every
> > coral that is tasty to them.  It is fairly safe to postulate that if we
> > remove a thousand COTS, that we have saved roughly 300,000 corals per
> year
> > for several years.  Therefore, COTS removal can be very effective as
> even a
> > one-off intervention to help deal with this emergency.  We have an
> > opportunity to protect and nurture pockets of reef and to encourage
> > accelerated recovery. The development of resilience to future bleaching
> > events will then occur, as these pockets of health end up becoming filled
> > with thermally adapted corals.  Of course the bigger picture issues must
> be
> > dealt with as well, but this approach can reinforce and support MPAs,
> > because without corals MPAs function poorly.
> >
> > Whether COTS removal is an effective long-term strategy under normal
> > conditions was not my point of discussion.  We sometimes do it for
> > community involvement as much as to save corals.  Of course no-take MPAs
> > and nutrient control are better long-term solutions that address the root
> > causes of predator over-abundance, but you have to have a strategy to get
> > fishing community support, and this type of activity builds support
> > while offering a very real short-term solution to increase coral cover
> and
> > fish habitat, as Janis and Brooks and many others will testify.
> >
> > Again, my original point is that we have an opportunity to act NOW, and
> so
> > I shared a new idea that has potential to motivate communities, NGOs, and
> > hopefully scientists, and that helps give the surviving corals a future
> and
> > the people involved more hope.   The key element of the strategy is to
> keep
> > the precious corals that survive alive even after the bleaching abates,
> and
> > by whatever means that are at our disposal. This will include predator
> > removal and the collection and propagation of corals that thrive in spite
> > of hot water and post-stress disease.
> >
> > Shouldn't we protect these survivors like we would precious gold and
> > diamonds?  We put our precious cash and heirlooms into secure banks, and
> so
> > why not create secure "gene bank nurseries" for cultivating resilient
> > corals (temperature, disease, etc.).  This is exactly what we have done
> in
> > Belize and the Dominican Republic, and we are then using second
> generation
> > fragments trimmed from the nurseries, to restore coral cover to rather
> > sizable patches within no-take MPAs where the Acropora corals have not
> > returned in spite of other types of management.
> >
> > We did all of this in spite of opposition from certain of you within the
> > coral reef research community, who went so far as to publish a formal
> > position paper that dismissed our efforts, based on incorrect assumptions
> > about what we were actually doing.  Of course the opposition made it very
> > difficult to access funding.  I hope that our ultimate success has now
> made
> > it clear that certainly there is room for every approach.
> >
> > Austin
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