[Coral-List] New article on parrotfish mediation on sponge-coral interactions

Juan Carlos Marquez Hoyos juanitomarquez at yahoo.com
Wed Jan 25 08:38:04 EST 2012

Dear colleagues:
Let me draw your attention on the online version of a new article:
Juan C. Márquez, Sven Zea. 2012. Parrotfish mediation in coral mortality and bioerosion by the encrusting, excavating sponge Cliona tenuis. Marine Ecology. Article first published online: 23 JAN 2012, 
DOI: 10.1111/j.1439-0485.2011.00506.x
You may access it in:
If you do not have Access, write me back and I will send you a pdf. 

The parrotfish Sparisoma viride often grazes live coral from edges undermined by the Caribbean encrusting and excavating sponge Cliona tenuis. To test whether parrotfish biting action has an effect on the dynamics 
of the sponge–coral interaction, we manipulated access of parrotfishes 
to the sponge–coral border in two species of massive corals. When 
parrotfish had access to the border, C. tenuis advanced significantly more slowly into the coral Siderastrea siderea than into the coral Diploria strigosa. When fish bites were prevented, sponge spread into S. siderea was further slowed down but remained the same for D. strigosa. Additionally, a thinner layer of the outer coral skeleton was removed 
by bioerosion when fish were excluded, a condition more pronounced in D. strigosa than in S. siderea. Thus, the speed of sponge-spread and the extent of bioerosion by 
parrotfish was coral species-dependent. It is hypothesized that coral 
skeleton architecture is the main variable associated with such 
dependency. Cliona tenuis spread is slow when undermining live S. siderea owing to the coral’s compact skeleton. The coral’s smooth and hard 
surface promotes a wide and shallow parrotfish bite morphology, which 
allows the sponge to overgrow the denuded area and thus advance slightly faster. On the less compact skeleton of the brain coral, D. strigosa, sponge spread is more rapid. This coral’s rather uneven surface 
sustains narrower and deeper parrotfish bites which do not facilitate 
the already fast sponge progress. Parrotfish corallivory thus acts 
synergistically with C. tenuis to further harm corals whose skeletal architecture slows sponge lateral spread. In addition, C. tenuis also appears to mediate the predator–prey fish–coral interaction by attracting parrotfish biting.
Juan C. Márquez, Ph.D.
McMaster University, Department of Biology
Life Sciences Building, Rm. 302
1280 Main St. West, Hamilton ON Canada L8S 4K1
Phone: 905.525.9140 Ext. 23041 
Fax: 905.522.6066
juancmarquezh at gmail.com

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