[Coral-List] sea urchin removal to prevent bioerosion

Michael Risk riskmj at univmail.cis.mcmaster.ca
Thu Feb 18 15:54:02 EST 2010


Dear Paul.

I agree with your sentiments, but not your phrasing. I think you meant
to say, "Out of kilter."

"Out of kilt" refers to mating Scotsmen.

Please feel free to contact me should you have further questions about
Scotsmen or watches.

MJR

On Wed, 17 Feb 2010 13:55:22 -0600
 "Paul Sammarco" <psammarco at lumcon.edu> wrote:
> Dear Bill,
> 
> Hello.  Well said.  
> 
> I think that if one is going to try to change a system, it is best
> done in
> small increments - and only to certain limits.  Ecological
> communities are
> very sensitive, despite our perception of them.  I consider them to
> be like
> Swiss watches, where each population represents a gear.  You can
> change the
> abundance of one population if you'd like - and turn that gear.  In
> doing
> that, some other gears will move very slightly because they are much
> larger.
> Indeed, they will hardly be affected at al.  Others, where the gears
> are
> about the same size, will move at about the same rate.  Others - much
> smaller ones, however, will move much faster.  
> 
> Plus, even if a system appears to be "out of kilt" to our eyes, in
> fact -
> even if it is "out of kilt", it is probably resting at some sort of
> equilibrium.  Thus, if we remove a large component of the community,
> we
> throw it into a highly dynamic disequilibrium.  
> 
> This is what the Australians recently found out when they removed all
> of the
> feral cats from Macquarie Island, 100 yrs after their introduction.
>  40% of
> the vegetative cover on the island was rapidly lost because the
> rabbit
> populations, held in check by the feral cats, exploded.  Now the bird
> populations are being affected as well (Bergstrom et al., 2009;
> Casey,
> 2009).  
> 
> Food for thought.  
> 
> 
> Cheers,
> 
> Paul
> 
> 
> 
> Bergstrom, D.M., A. Lucieer, K. Kiefer, J. Wasley, L. Belbin, T.K.
> Pedersen,
> and S.L. Shown.  2009.  Indirect effects of invasive species removal
> devastate World Heritage Island.  J. Appl. Ecol. 46:  73-81.  
> 
> Casey, M.  2009.  Species eradication backfires big time.  CBS News,
> Jan.
> 13, 2009,
> http://www.cbsnews.com/stories/2009/01/13/tech/main4719190.shtml
> 
> 
> 
> 
> Paul W. Sammarco, Ph.D.
> Executive Director
> Association of Marine Laboratories of the Caribbean (AMLC)
> 
> and
> 
> Professor
> Louisiana Universities Marine Consortium (LUMCON)
> 8124 Hwy. 56
> Chauvin, LA  70344
> USA
> 
> Tel:                1-985-876-2489
> FAX:              1-985-851-2874
> Email:           psammarco at lumcon.edu
> Website:     www.lumcon.edu
> 
> 
> -----Original Message-----
> From: coral-list-bounces at coral.aoml.noaa.gov
> [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Bill
> Allison
> Sent: Wednesday, February 17, 2010 10:54 AM
> To: Clement Dumont
> Cc: coral-list at coral.aoml.noaa.gov
> Subject: Re: [Coral-List] sea urchin removal to prevent bioerosion
> 
> There was a effort made to remove control the abundance of
> Strongylocentrotus droebachiensis on off Nova Scotia in the early
> 1980s
> followed by a mass mortality in about 1983 that may be instructive.
> Try
> Marine Biology (Mann, Wharton, Scheiberling, others). If I am not
> mistaken a
> retrospective paper on the removal exercise and its conceptual
> rationalization concluded that it was misconceived.
> 
> On Wed, Feb 17, 2010 at 3:01 AM, Clement Dumont <cdumont at hku.hk>
> wrote:
> 
> > Dear all,
> > thank you for all the comprehensive replies from which I learned a
> lot. My
> > initial question, however, remained unanswered. Does anybody is
> aware of
> > report/publication of such removal practice of grazers to
> protect/restore
> > coral reefs (i.e. removal program similar to the crown-of thorns)?
> >  I have also a project in Malaysia where the Marine Park rangers
> remove
> > every year the sea star Acanthaster planci in an attempt to prevent
> > population outbreaks. However, when I found similar densities of
> sea stars
> > at the sites where removal occur with sites where no sea stars are
> > collected. Unthinking removal programs are generally unsuccessful
> and can
> > even further damage the corals (e.g. Japan sea star removal).
> >
> > Best wishes,
> > Clement
> >
> > ---------
> > Date: Thu, 11 Feb 2010 08:54:02 +0800
> > From: Clement Dumont <cdumont at hku.hk>
> > Subject: [Coral-List] sea urchin removal to prevent bioerosion
> > To: "coral-list at coral.aoml.noaa.gov"
> <coral-list at coral.aoml.noaa.gov>
> > Message-ID:
> >
>
       <A079DF1679D36540A0B97A14317E122A12B13FA575 at MAIL.hkucc-com.hku.hk>
> > Content-Type: text/plain; charset="us-ascii"
> >
> > Dear all,
> > the Hong Kong government took the initiative (based on brief
> observations)
> > to remove every year thousands of the sea urchin Diadema setosum
> and the
> > corallivore snail Drupella sp. to prevent the excessive bioerosion
> of
> corals
> > (but no studies have been conducted). Being really surprised by
> this
> > initiative, I started a cage experiment with different densities of
> urchin
> > to examine whether Diadema is the major factor contributing to
> bioerosion.
> > With no much surprise (the experiment is still running), we have a
> higher
> > recruitment of macroalgae and also higher sedimentation on corals
> > non-exposed to sea urchin grazing and even with high densities
> densities
> of
> > urchins, still no sign of bioerosion. Hong Kong waters are highly
> polluted
> > and the nutrient enrichment and high sedimentation may rather be
> the main
> > causes of corals degradation.
> > I am therefore curious whether such sea urchin removal practice
> (not on a
> > fishery purpose) is/has been conducted elsewhere to prevent
> bioerosion of
> > corals.
> >
> > Thanks,
> > Clement
> >
> > ----
> > Clement Dumont
> > Research Assistant Professor
> > The Swire Institute of Marine Science
> > & The Division of Ecology & Biodiversity
> > The School of Biological Sciences
> > The University of Hong Kong
> > Pokfulam, Hong Kong, PR China
> >
> > Phone: (852) 51 99 1730
> > Webpage: http://web.hku.hk/~cdumont/
> <http://web.hku.hk/%7Ecdumont/>
> >
> >
> > _______________________________________________
> > Coral-List mailing list
> > Coral-List at coral.aoml.noaa.gov
> > http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
> >
> 
> 
> 
> -- 
> Reality, as usual, beats fiction out of sight.
> Conrad, 1915
> 
> "Reality" is a dangerous word that should always be incarcerated in
> quotation marks.
> Nabokov
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Mike Risk
Marine Ecologist
PO Box 1195
Durham Ontario
N0G 1R0



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