[Coral-List] Eradicating Trididemnum solidum

Thomas Goreau goreau at bestweb.net
Thu Jan 17 10:20:53 EST 2008

Dear Jessica,

That is a good point! I try to dump the fragments on sand where they  
will hopefully die without attaching, but I'm not sure of their fate.  
Too much to stick in my bathing suit and dump on land!

Fascinating information! Can you email me pdfs of these papers? Do  
you have photos of the beast? What I find fascinating about the  
Didemnids is their incredible range of morphology. The tropical ones  
all seem to have symbiotic algae (cyanobacteria), but do the cold  
water ones too?

To what to you attribute their recent success? Are they eating  
zooplankton? Bacteria? Why do they seem to spread in euttrophic  
habitats? Are their cyanobacteria especially good at taking up  
dissolved nutrients?

Best wishes,

On Jan 17, 2008, at 8:32 AM, Jessica Craft wrote:

> Thomas,
> I don't know the literature on T. solidum, but for a rapidly expanding
> mat tunicate, known as Didemnum sp. in more northern waters,  
> pulling the
> mats off is not recommended as this highly invasive species spreads
> rapidly and broken fragments can wedge themselves into the hardbottom
> and spread new colonies.  This particular species is running  
> rampant all
> over the globe now: along the northeast and northwest coasts of the
> U.S., Europe, New Zealand and Japan.  It is now covering a large  
> expanse
> of the Georges Bank. Recently we've observed it beginning to spread  
> off
> the east coast of Nantucket. Perhaps invasive and nuisance mat  
> tunicates
> are the new threat to coral and hardbottom communities? Add them to  
> the
> list...
> References:
> Bullard, S. G., Lambert, G., Carman, M. R., Byrnes, J., Whitlatch, R.
> B., Ruiz, G., Miller, R. J., Harris, L., Valentine, P. C., Collie, J.
> S., Pederson, J., McNaught, D. C., Cohen, A. N., Asch, R. G.,  
> Dijkstra,
> J. and Heinonen, K. 2007. The colonial ascidian Didemnum sp. A:  
> current
> distribution, basic biology, and potential threat to marine  
> communities
> of the northeast and west coasts of North America. J. Exp. Mar. Biol.
> Ecol. 342: 99-108.
> Valentine, P. C., Collie, J. S., Reid, R. N., Asch, R. G., Guida,  
> V. G.
> and Blackwood, D. S. 2007. The occurrence of the colonial ascidian
> Didemnum sp. on Georges Bank gravel habitat - Ecological observations
> and potential effects on groundfish and scallop fisheries. J. Exp.  
> Mar.
> Biol. Ecol. 342: 179-181
> Bullard,SG, Sedlack, B, Reinhardt, JF, Litty, C, Gareau, K, Whitlatch,
> RB. 2007. Fragmentation of colonial ascidians: Differences in
> reattachment capability among species. J. Exp. Mar. Biol. Ecol. 342:
> 166-168
> Jessica A. Craft
> Marine Biologist
> Coastal Planning & Engineering, Inc.
> Marine Science & Biological Research
> 2481 NW Boca Raton Blvd.
> Boca Raton, FL 33431
> Ph 561-391-8102
> Fax 561-391-9116
>           o
>> <))>o              o
>> <))>o
> -----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 4:51 PM
> To: coral-list coral-list
> Cc: Roger Dunton
> Subject: [Coral-List] Eradicating Trididemnum solidum
> Sorry to pile on, but I did not answer Roger Dunton's key question:
> what to do?
> I always pull off all I can, because this is real pest, and it is
> killing huge amounts of coral. You feel good to save a bit of coral,
> but it is almost hopeless because there is so much of it.  So you can
> wind up not seeing anything else and using up all your air.
> They klll coral by smothering, not by biological predation or
> chemical toxicity, there is no reaction by the coral to the
> encroaching threat. Nothing seems to eat it, but Roger Dunton's
> observations of the worms are really fascinating.
> We really don't know why this has become such a plague in places
> where it did not used to be. It used to be very very rare in Jamaica
> for many decades and suddenly began to spread and spread. Because
> tunicates are thought to rely on the same resources as corals,
> zooplankton and photosynthetic symbionts, it is a little hard to know
> why they are taking over so much, and my guess is it must be a
> trophic shift of a subtle kind, I suspect related to changes in the
> ocean plankton food chain that are pervasive, but not the same
> everywhere.
> 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
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Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

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