[Coral-List] SPAM R2: Re: Parrotfishes and coral reef health

Julian julian at reefcheck.org.my
Fri Feb 17 22:28:34 EST 2017

Dear Peter and others
This is truly an interesting discussion. But, forgive me for being
simplistic, what are reef managers supposed to do while you are finding out
the correct answer to this "non-binary" issue? Any suggestions would be

Julian Hyde
General Manager
Reef Check Malaysia
+60 3 2161 5948
Follow us on Facebook at www.facebook.com/rcmalaysia


-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Peter Sale
Sent: Saturday, 18 February, 2017 12:22 AM
To: tmcclanahan at wcs.org; coral-list at coral.aoml.noaa.gov; Dennis Hubbard; Les
Kaufman (lesk at bu.edu); jlang at riposi.net
Subject: SPAM R2: Re: [Coral-List] Parrotfishes and coral reef health

Kudos to Tim McClanahan, in particular, for quietly reintroducing a touch of
realism into this discussion.  Coral reef decline is proceeding around the
world, but seems to me to be particularly severe in the Caribbean.  (Perhaps
that is because of the relatively small number of primary reef builders in
that system, some of which have been savagely hit by disease.)  The decline
is caused by many concurrent stressors (Judy Lang's post hit most of them in
one sentence).  The relative importance of these stressors varies from place
to place, and from time to time.  The long-term trajectory looks very bleak.

I doubt any of you disagree with my first paragraph.  But if we reef
scientists, and particularly the reef ecologists amongst us, cannot remember
that this is a case of simultaneous, possibly synergistic, stressors acting
in different ways on different species when we discuss what is happening,
how can we expect other people to comprehend the magnitude of the problem?
To spend lines and lines of text on coral-list debating whether or not
parrotfish grazing is to blame (as if one factor will be the leading cause
of decline across time and space) cheapens the discussion and reduces any
chance of articulating clearly what is needed to gain some improvement.  We
can all do better.

And please, let us stop reducing the concept of herbivory, by parrotfishes,
sea urchins or anybody else, to a simple binary interaction between the
grazer and the macroalgae, with the corals waiting patiently on the outcome.
What utter nonsense.  It's been well documented in numerous marine
environments that algae of different species respond differently to grazing
pressure.  Most macroalgae escape most of the herbivore guild through
growth, so that the suite of herbivores that might keep a bare site free of
anything other than a fine algal turf is quite incapable of returning a lush
stand of macroalgae to that fine turf state.  Different species of
macroalgae are differentially palatable to different species of herbivore,
are differentially impacted by pollution, by nutrients, by storms.  I could
go on.  Even understanding the algal-herbivore interaction requires much
more subtle ecological insights than are evident when all parrotfishes and
all algae are considered interch  angeable.  If we do not improve the way in
which we talk about the loss of living coral on our coral reefs, we diminish
the chance of really understanding what is happening, or potentially
discovering effective management actions.  We are all capable of elevating
the level of discourse.  If the world is destined to lose most of its coral
reefs this century, I'd like to think that at minimum, we had at least
learned what was happening, and could articulate what would have been needed
to prevent that eventual demise.  We cannot learn from our mistakes without
understanding clearly what has happened, and the eventual demise of coral
reefs, if it does happen, needs to become a teachable moment.

Peter Sale
University of Windsor

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