[Coral-List] Palythoa overgrowing corals in Trinidad and elsewhere

Thomas Goreau goreau at bestweb.net
Mon Mar 10 17:03:00 EDT 2008

Dear Dawn,

Glad to hear you and Stanton were in the field, and looking forward  
to your observations.  I think you will remember that we looked at  
the earliest studies of these sites, and Palythoa seems to have  
expanded landward quite a bit. The salinities are near normal, but  
the turbidity is extremely high for coral reefs, and I think that the  
Zoanthus may be able to feed of particulate organic carbon to some  
degree, which might give them an edge. The factors at the cold limits  
are presumably different, those areas are all pretty turbid too, but  
nothing like Trinidad!

Best wishes to all,

On Mar 10, 2008, at 4:53 PM, Dawn Phillip wrote:

> Stanton and I have just come back from a trip to survey the two  
> coral systems at Toco.  We noticed that Palythoa seemed to be  
> dominant in specific bands on the reef, particularly on the reef  
> crest.  It is easy to discern a Palythoa zone at low tide by  
> looking down at the ‘reef’ from the top of the cliff.  Apart from  
> overgrowing hard coral and rocks, we have seen Palythoa overgrowing  
> Zoanthus, fire coral and anemones.
> On a side, water salinities in this area are usually between 34 –  
> 35 p.s.u., which does not support the hypothesis of any significant  
> influence by the large South American rivers.
> Dr Dawn A.T. Phillip
> Lecturer
> Department of Life Sciences
> The University of the West Indies
> St Augustine
> Trinidad and Tobago
> Ph: (868)662-2002 ex. 2208
> Mobile: (868)394-3005; (868)464-6932
> Fax: (868)663-5241
> Email: dawn.phillip at sta.uwi.edu
> Web: http://www.sta.uwi.edu/fsa/lifesciences/dphillip.htm
> From: Thomas Goreau [mailto:goreau at bestweb.net]
> Sent: Monday, March 10, 2008 1:46 PM
> To: coral-list coral-list
> Cc: Dawn Phillip; Jennie Mallela; Lee Ann Beddoe; Stanton Belford;  
> João Gama Monteiro; Dan and Stephanie Clark; James Reimer
> Subject: Palythoa overgrowing corals in Trinidad and elsewhere
> Palythoa overgrowth of corals is being studied in Toco and Salybia,  
> Trinidad, by a research group at the University of the West Indies  
> at St. Augustine including Dawn Philip, Jennnie Mallela, Lee Ann  
> Beddoe, and Stanton Belford. Our observations, compared to earlier  
> work by other Trinidadian researchers, shows that Palythoa is  
> clearly overgrowing corals and expanding over the reef flat.
> We see the same thing happening on a large scale in Broward County  
> Florida, where Dan Clark and I just photographed this last week,  
> and where large old corals are being overgrown. The same Palythoa  
> dominance is common in southern Brazil, for example from Cabo Frio  
> and Arraial do Cabo southwestwards. Palythoa mats dominate large  
> areas of the reefs of Cabo Verde, and photos sent to me last week  
> by Joao Gama Monteiro show it is even overgrowing Millepora there.
> Palythoa is a pest in that it is toxic so it provides neither food  
> nor shelter, and it's spread at the expense of corals in many  
> places is a serious concern, but the ecological factors allowing it  
> to spread are not known. One possibility is that food supplies that  
> Palythoa is a more effective consumer of than corals are  
> increasing, but little is known of the feeding habits of Palythoa,  
> according  James Reimer, a zoanthid expert I specifically asked  
> about this a few years ago.
> Trinidad is an interesting exception to the general rule in that  
> the other places where Palythoa is dominant are near the extreme  
> cold limit of corals, which Trinidad is not, however it is near the  
> extreme sedimentation limit of corals due to the influence of the  
> Orinoco River.
> Thomas J. Goreau, PhD
> President
> Global Coral Reef Alliance
> 37 Pleasant Street, Cambridge MA 02139
> 617-864-4226
> goreau at bestweb.net
> http://www.globalcoral.org
> Message: 5
> Date: Fri, 7 Mar 2008 16:44:43 -0400
> From: "Jan-Willem van Bochove" <jvb at coralcayconservation.com>
> Subject: [Coral-List] Zoanthid (Paltythoa caribaeorum) overgrowth of
>             corals
> To: <coral-list at coral.aoml.noaa.gov>
> Message-ID: <20080307205035.40516179F5 at coral.aoml.noaa.gov>
> Content-Type: text/plain;           charset="us-ascii"
> Hello,
> I've noticed that P. caribaeorum, a colonial zoanthid which forms  
> extensive
> mats, is overtopping and smothering a large variety of  
> scleractinian corals
> in shallow reef environments in Tobago.
> P. caribaeorum is an aggressive, fast growing and toxic zoanthid  
> which seems
> to stop at nothing and I have yet to see any significant predation  
> on the
> species. In a small, sheltered bay where most of our observations  
> were made,
> it forms the dominant substrate with over 75% cover in the shallows  
> (2-5m).
> We have also seen it overtopping massive corals in deeper waters.
> I was wondering if anyone has or knows of any recent research done  
> on the
> zoanthid or has noticed its abundance elsewhere on such a scale.  
> Other than
> a paper presented at the ICRS of 1981 in Manila by Suchanek and  
> Green, I
> have not come across any literature dealing with inter-specific  
> competition
> with corals.
> Images of the zoanthid overgrowing corals can be found on -
> http://www.flickr.com/photos/23314528@N03/
> Any feedback is appreciated.
> Regards,
> Jan
> Reference -
> Suchanek T.H., and Green, D.J., 1981. Interspecific Competition  
> Between
> Palythoa Caribaeorum and Other Sessile Invertebrates on St.Croix  
> Reefs, U.S.
> Virgin Islands. Proceedings of the Fourth International Coral Reef
> Symposium, Manila, Vol. 2.
> -- 
> Jan-Willem van Bochove MSc
> Chief Technical Advisor
> Coral Cay Conservation Ltd
> Elizabeth House, 39 York Road, London, SE1 7NJ, United Kingdom
> Tel: +44 (0)20 7620 1411 (switch board)
> Fax: +44 (0)20 7921 0469
> email: jvb at coralcayconservation.com
> www.coralcay.org
> skype: jhvanbochove

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

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