[Coral-List] sea urchin removal to prevent bioerosion

Wed Feb 17 16:32:04 EST 2010

That reminds me of a tale that that may be a myth but if true is an object
lesson and a contender for the all-time Swiss watch-breaking championship.

It seems that a half century or so ago the members of a hunt and fish club
in Colorado had a problem. A trash fish was, they believed, adversely
affecting the game fish population. Various attempts to control the trash
fish population had failed so they decided to kill all of the fish in the
lake with dynamite, then restock it with what they deemed desirable. As
ignorant and stupid as this seems on ecological grounds, it was geology, not
the ecological complexities that defeated them - utterly. The lake was
underlain by very porous ground and the dynamite blast shook up the sediment
occluding the pores. The lake drained.

I would dearly love to read the original account but so far no luck finding
it.

Bill

On Wed, Feb 17, 2010 at 2:55 PM, 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/> <
> 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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>

-- 
Reality, as usual, beats fiction out of sight.
Conrad, 1915

"Reality" is a dangerous word that should always be incarcerated in
quotation marks.
Nabokov