[Coral-List] Tunicate-killing coral spreading all across Caribbeanregion

Janie Wulff wulff at bio.fsu.edu
Thu Jan 17 11:41:45 EST 2008

In a 1995 Marine Ecology paper (P.S.Z.N.I. Mar Ecol 16:145-163), 
Brian Bingham and Craig Young remark that they observed the polyclad 
flatworm Pseudoceros crozieri feeding on zooids of Ecteinascidia 
turbinata colonies until only basal stolons remained.

-Janie Wulff

At 5:56 PM -0500 1/16/08, Thomas Goreau wrote:
>Dear Alina,
>This is a very interesting idea, but what could eat them, and why 
>don't we see signs of them being chewed in the field?
>In fact I've not seen any tunicate anywhere being chewed, even in 
>Indonesia with the highest diversity of tunicates and fish in the 
>world, where you would expect some predator would have evolved a way 
>to exploit and abundant food resource. I hope someone can prove me 
>wrong, because we need a lot more of such a predator.......
>Tunicates seem to be very toxic, even the ones that are soft and seem 
>to have no protection at all are not eaten. Some tunicates are known 
>to have very high Vanadium contents, but nobody seems to know how 
>general this is, or at least I don't.
>Also, why would the worst infestations I've seen be in the Washington 
>Slaagbai Park in Bonaire, which is about the most really strictly 
>protected and local pollution free place in the entire Caribbean?
>And since they are photosynthetic, they need full light exposure. You 
>can clearly see they grow best on the top surfaces of corals so they 
>don't make a good cryptic organism.
>Best wishes,
>On Jan 16, 2008, at 5:42 PM, Szmant, Alina wrote:
>>  My bet is that there is decreased predation on the tunicate.  They are
>>  usually chemically defended, and I have no idea what eats them.  Most
>>  tunicates and other fleshy inverts tend to be cryptic to protect 
>>  against
>>  predation.  Release from predation allows them to grow out in the 
>>  open.
>>  Caging studies published back in 80s (work by Day and others, 
>>  references
>>  not handy) showed this.
>>  I have also seen a high frequency of these mats especially growing up
>>  the columns of Montastraea annularis.
>>  Alina
>>  *******************************************************************
>>  Dr. Alina M. Szmant
>>  Coral Reef Research Group
>>  UNCW-Center for Marine Science
>>  5600 Marvin K. Moss Ln
>>  Wilmington NC 28409
>>  Tel: (910)962-2362 & Fax:  (910)962-2410
>>  Cell:  (910)200-3913
>>  email:  szmanta at uncw.edu
>>  Web Page:  http://people.uncw.edu/szmanta
>>  ******************************************************************
>>  -----Original Message-----
>>  From: coral-list-bounces at coral.aoml.noaa.gov
>>  [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Thomas
>>  Goreau
>>  Sent: Wednesday, January 16, 2008 4:17 PM
>>  To: coral-list at coral.aoml.noaa.gov
>>  Subject: [Coral-List] Tunicate-killing coral spreading all across
>>  Caribbeanregion
>>  Dear Alex,
>>  The tunicate is Trididemnum solidum. This very effective coral killer
>>  has greatly increased in many locations all around the Caribbean, but
>  > much more in some places than others. I think the first description
>>  of it overgrowing coral was by Chuck Birkeland when he was a post-doc
>>  in Belize, and it was at that time a rare curiosity. 10 years ago
>>  when I told him it was no longer a novelty and had become a big
>>  problem, he was very  surprised. I began noticing it spreading in
>>  Jamaica around 1990. Rolf Bak began noticing its spread in Curacao
>>  and Edwin Hernandez Delgado in Puerto Rico about 10 years ago, around
>>  the time that I alerted Cozumel divers to it. I've seen quite a bit
>>  of it in St. Martin, the Grenadines, Tobago, Panama, Cozumel, Turks
>>  and Caicos, and Bonaire, where the worst infestations I have ever
>>  seen were at the very north end of the island, with around 40% of the
>>  coral surfaces overgrown.  In some places colonies are more whitish
>>  cream colored, or beige, but in some places they have distinct green
>>  or blue tints due to their symbiotic cyanobacteria. For example those
>  > in north eastern Jamaica are more blue.
>>  There is at least one similar didemnid in the Indo-Pacfic with a
>>  rubber mat like consistency. But the other Didemnids there look very
>>  different, and are not thick and rubbery but thin and brightly
>>  colored. Some are very common but do not overgrow corals, like
>>  Didemnum molle, which can be brown and white or green and white, but
>>  other species can grow so fast that they overgrow corals. After the
>>  1998 high temperature mortality of corals in Indonesia, tunicates,
>>  not algae, overgrew the dead coral very quickly, to my surprise. In
>>  Sri Lanka in 1997 I found a green didemnid that grew so fast it was
>>  smothering macrophytic algae, especially Halimeda.
>>  As far as I have been able to find out from the tunicate specialists
>>  at the Smithsonian, there seems to be little or no work on what they
>>  actually eat, but they are presumed to eat the same sort of
>>  zooplankton as corals. That seems to me not be correct, because there
>>  has been a dramatic increase in their abundance and killing of
>>  corals, and it looks as though something they can eat better than
>>  corals can must be increasing. The fact that the highest abundances
>>  of T, solidum in Bonaire is in a protected area with uninhabited
>>  areas downstream with no human pollution at all implies this must be
>>  some sort of a natural trophic shift, perhaps related to changes in
>>  upwelling in the Cariaco Trench. For sure this pest is increasing all
>>  over the Caribbean, but at very different rates, and the different
>>  abundances may have some clue into changes in its food supply. What
>>  is driving it needs to be worked out, because a lot of coral is being
>>  killed by it. This would make a good topic for students!
>>  Hope to catch up with you in Cocle this year, on the way to Azuero!
>>  Best wishes,
>>  Tom
>>  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
>>>  Date: Wed, 16 Jan 2008 12:44:25 -0500
>>>  From: Alex Brylske <Brylske at aol.com>
>>>  Subject: [Coral-List] Fwd: Mat tunicate problem?
>>>  To: coral-list coral-list <coral-list at coral.aoml.noaa.gov>
>>>  Message-ID: <1302C019-EB0C-4D70-91E9-CACFEABC2D8A at aol.com>
>>>  Content-Type: text/plain;	charset=WINDOWS-1252;	format=flowed;
>>>	delsp=yes
>>>  Received this letter from a reader, and would appreciate some insight
>>>  from the group. Is he talking about some kind of colonial tunicate?
>>>  Sorry, he didn't send any images.
>>>  Alex
>>>  Alex Brylske, Senior Editor
>>>  DIVE TRAINING magazine
>>>  Address:
>>>  4314 SW 18th Place
>>>  Cape Coral, FL 33914
>>>  Phone: 239-471-7824
>>>  Cell: 954-701-1966
>>>  Fax: 281-664-9497
>>>  E-mail: brylske at aol.com
>>>  Website: www.dtmag.com
>>>  Begin forwarded message:
>>>>  From: Roger Dunton <roger335 at comcast.net>
>>>>  Date: January 16, 2008 12:26:47 PM EST
>>>>  To: Alex Brylske <brylske at aol.com>
>>>>  Subject: Mat tunicate problem?
>>>>  Alex,
>>>>  While leading a group in Cozumel this Christmas, I met a lovely
>>>>  couple who pointed out what we believe may be a problem infestation
>  >>> of the coral reefs. I am including their description to see if you
>>>>  are aware of this and perhaps what might be done. They referred to
>>>>  it as a ?MAT TUNICATE?, but it was unlike any tunicates of which I
>>>>  am aware.
>>>>  ?First of all, we are not sure of the name, it was given to us by a
>>>>  dive master in Belize on Turneffe Island.  We have looked through
>>>>  the name on internet but did not find anything close to it.
>>>>  Whatever its name, this algae is light grey - a bit greenish, and
>>>>  when taken to surface it is actually a pale pink.  It is thick and
>>>>  feels rather soft to touch, like leather.  It covers the coral like
>>>>  a blanket.  Actually when you look close, it seems to start with a
>>>>  small drop, and you can see several drops like sprayed from above.
>>>>  Each drop seems to develop into a blanket that covers the whole
>>>>  coral head it started on, and grows along the stems of fans and
>>>>  sponges until it covers it entirely.
>  >>>
>>>>  The dive master in Belize indicated that the algae should be
>>>>  removed, or at least untucked from the coral head on the edges to
>>>>  stop its growth.  When you do this, it is sometimes easy and comes
>>>>  in large pieces, sometimes it breaks into small crumbs.  Below the
>>>>  blanket, the coral is dead, and it seems there is only rock.  There
>>>>  are often thin spiders with long legs or long worms between the rock
>>>>  and the algae.  The algae is soft when taken off the coral, and when
>>>>  it dries on the surface it becomes rigid.
>>>>  We have seen it a lot in Belize on the East side of Turneffe Island,
>>>>  and we start to see it a lot in Cozumel, at about any depth.  We
>>>>  have not been able to observe a pattern, but I thought there was
>>>>  maybe more of it in shallower waters.  The weird thing is that when
>>>>  you start looking for it, you see it a lot whereas if you are not
>>>>  looking, you don't notice it so much.
>>>>  I would be interested in learning what it is, and what should be
>>>>  done with it: remove it and dispose of it at surface, or just untuck
>>>>  it, or leave it alone?
>>>>  Thank you for any light you might shed on this.?
>>>>  -Roger Dunton
>>  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
>>  _______________________________________________
>>  Coral-List mailing list
>>  Coral-List at coral.aoml.noaa.gov
>>  http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>Thomas J. Goreau, PhD
>Global Coral Reef Alliance
>37 Pleasant Street, Cambridge MA 02139
>goreau at bestweb.net
>Coral-List mailing list
>Coral-List at coral.aoml.noaa.gov

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