[Coral-List] Zoanthid (Paltythoa caribaeorum) overgrowth of corals

Walczak, Joanna Joanna.Walczak at dep.state.fl.us
Mon Mar 10 12:38:14 EDT 2008

Hi Jan,

  I just recently finished my Masters thesis on the population dynamics of
Palythoa caribaeorum on southeast Florida reefs.  Although my study was not
designed to specifically address competition with corals, I did look at the
mean percent live covers (cm²) of Palythoa [using the software Coral Point
Count with Excel extensions (CPCe) (Kohler & Gill 2006)] and stony corals
[from historical monitoring data (Gilliam et al. 2007)] at 16 permanent
monitoring sites [Belt quadrat transects - see Dodge et al. (1982)], from
2002-2006.  Although I could not statistically compare the two, neither
population changed size significantly over the study period.  


My study focused on Broward County, FL, where the reefs are composed of
three, increasingly deeper, shore-parallel, linear reef terraces, (Inner,
Middle, and Outer Reefs)  and an Inshore Ridge Complex, located inshore of
the Inner reef (Moyer et al. 2003; Banks et al. 2007; Walker et al. in
press).  The southeast Florida high-latitude reef communities are comprised
of coral reefs, and colonized hardbottom, where the biota present generally
consists of variable populations of stony corals, octocorals, sponges,
zoanthids, and macroalgae (Moyer et al. 2003; Collier et al. 2007; Walker et
al. in press).  Although the literature suggests (and your personal
observations confirm) that Palythoa is an incredibly aggressive competitor
for space, my study suggests that (in southeast Florida) the Palythoa
population is actually maintaining size.  This follows the Tanner (1997),
theory that an unknown population equilibrium maximum may exist, at which
point the population will focus its energy on maintenance, rather than


Basically, southeast Florida is a prime location for Palythoa domination.
Our reefs have the space for growth, and have plenty of nutrients available,
but something is keeping the population size in check. 


As for predation, you are correct that there really are no significant
predators... the only mention in the literature is that the fireworm
Hermodice carunculata likes to munch on injured or diseased colonies.  The
combination of the palytoxin and the sediment retained in their walls
(Haywick and Mueller 1997) probably isn't very appetizing. :-)


Although this information may not directly help you, I have provided a
sampling of the papers I used in my thesis to help you find more information.


Please feel free to let me know if you have any questions.






 References - 


Acosta, A. 2001. Disease in Zoanthids: dynamics in space and time.
Hydrobiologia 460: 113-130.

Acosta, A., P. W. Sammarco, and L. E. Duarte. 2001. Asexual reproduction in a
zoanthid by fragmentation: the role of exogenous factors. Bulletin of Marine
Science 68: 363-381.

Bastidas, C., and D. Bone. 1996. Competitive strategies between Palythoa
caribaeorum and Zoanthus sociatus (Cnidaria: Anthozoa) at a reef flat
environment in Venezuela. Bulletin of Marine Science 59: 543-555.

Banks, K., B. Riegl, E. Shinn, W. Piller, and R. Dodge. 2007. Geomorphology
of the southeast Florida continental reef tract (Miami-Dade, Broward, and
Palm Beach Counties, USA). Coral Reefs 26: 617-633.

Boscolo, H. K., and F. L. Silveira. 2005. Reproductive biology of Palythoa
caribaeorum and Protopalythoa variabilis (Cnidaria, Anthozoa, Zoanthidea)
from the southeastern coast of Brazil. Braz. J. Biol. 65: 29-41.

Collier, C., R. Dodge, D. Gilliam, K. Gracie, L. Gregg, W. Jaap, M. Mastry,
and N. Poulos. 2007. Rapid Response and Restoration for Coral Reef Injuries
in Southeast Florida: Guidelines and Recommendations. Southeast Florida Coral
Reef Initiative. Pp. 57. Available at the URL:

Dodge, R. E., A. Logan, and A. Antonius. 1982. Quantitative reef assessment
studies in Bermuda: A comparison of methods and preliminary results. Bulletin
of Marine Science 32: 745-760.

Fadlallah, Y. H., R. H. Karlson, and K. P. Sebens. 1984. A comparative study
of sexual reproduction in three species of Panamanian zoanthids.
(Coelenterate: Anthozoa) Bull Mar Sci 35: 80-89.

Gilliam, D. S., R. E. Dodge, R. E. Spieler, L. K. B. Jordan, and J. C.
Walczak. 2007. Marine Biological Monitoring in Broward County, Florida:
Technical Report  06-01. Prepared for: Broward County Board of County
Commissioners Department of Planning and Environmental, Protection Biological
Resource Division.  Report prepared by: Nova Southeastern University
Oceanographic Center. 

Haywick, D. W., and E. M. Mueller. 1997. Sediment retention in encrusting
Palythoa spp.--a biological twist to a geological process. Coral Reefs 16:
39-46.Kohler, K. E., and S. M. Gill. 2006. Coral Point Count with Excel
extensions (CPCe): A Visual Basic program for the determination of coral and
substrate coverage using random point count methodology. Computers and

Moyer, R. P., B. Riegl, K. Banks, and R. E. Dodge. 2003. Spatial patterns and
ecology of benthic communities on a high-latitude South Florida (Broward
County, USA) reef system. Coral Reefs 22: 447-464.

Pérez, C. D., D. A. Vila-Nova, and A. M. Santos. 2005. Associated community
with the zoanthid Palythoa caribaeorum (Duchassaing & Michelotti, 1860)
(Cnidaria, Anthozoa) from littoral of Pernambuco, Brazil. Hydrobiologia 548:

Sebens, K. P. 1982. Intertidal distribution of zoanthids on the Caribbean
coast of Panama: effects of predation and desiccation. Bull. Mar. Sci. 32:

Tanner, J. E. 1997. The effects of density on the zoanthid Palythoa caesia.
The Journal of Animal Ecology 66: 793-810.

Walker, B. K., B. M. Riegl, and R. E. Dodge. 2008. Mapping coral reef
habitats in southeast Florida using a combined technique approach. Journal of
Coastal Research. In press.




Joanna C. Walczak

Coral Reef Conservation Program Coordinator/

MICCI Program Coordinator

Florida Department of Environmental Protection

Phone: 305-795-2111




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From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Jan-Willem van
Sent: Friday, March 07, 2008 3:45 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Zoanthid (Paltythoa caribaeorum) overgrowth of corals






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 -








Any feedback is appreciated.












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 

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