[Coral-List] Michael Risk - C. delitrix as measure of bioerosion

[Christine Schoenberg]

Dear Gregor and other Corallisters,

I have been following the discussion on bioerosion and bioeroding 
sponges with increasing interest. I have been looking into the 
nutrients/bioerosion question since about 1995 and have some (unpubl.) 
experimental results that point the same way as results from Mike Risk's 
group. Klaus Ruetzler from the Smithsonian in Washington noted increases 
in bioeroding sponge abundances in the Caribbean (Rutzler K 2002. Impact 
of crustose clionid sponges on Caribbean reef corals. Acta Geol 
Hispanica 37: 61-72). I have some more recent data on increased 
bioeroding sponge abundances on the Great Barrier Reef that I am 
presently trying to publish. I was quite impressed by these data and 
think it would be extremely important to obtain some more large-scale, 
long-term knowledge about all this, especially as I had some reports 
from non-sponge people who contacted me about possibly bioeroding 
sponges that seem to become epidemic at their sites (yet unconfirmed but 
not unlikely).

Since some time I have been trying to find some people who are able to 
conduct a quick monitoring project on bioeroding sponges in different 
parts of the world, repeated over an extended period of time, going to 
their own field sites maybe twice a year for a day or two to collect 
related data. Either following a simplified Holmes-protocol (see Holmes, 
KE 2000. Effects of eutrophication on bioeroding sponge communities with 
the description of new West Indian sponges, Cliona spp. (Porifera: 
Hadromerida: Clionidae). Invertebrate Biology, 119, 125–138 and Holmes, 
KE, Edinger, EN, Hariyadi, Limmon, GV & Risk, MJ 2000. Bioerosion of 
live massive corals and branching coral rubble on Indonesian coral 
reefs. Marine Pollution Bulletin, 40, 606–617) or some sort of simple 
transect study quantifying the 'top predators' in sponge bioerosion. 
Participants in this project need to be familiar with bioeroding 
sponges, i.e. need to be able to distinguish all bioeroding sponge 
species as in 'no. 1 differs from no. 2' (Holmes-approach) or to 
identify the 2 or 3 the most common species at their sites. So far I 
thought it would probably be better to involve sponge people who are 
experienced with the more important sponges, e.g. of the Cliona viridis 
species complex (very competitive, brown, symbiotic sponges, including 
species such as aprica, caribbaea, nigricans, papillae, tenuis, 
vallartense, varians, viridis) and maybe with the Cliona celata species 
complex (very common, including e.g. alderi, amplicalvata, californiana, 
celata, dissimilis, linearis, raphida), but maybe some coral people who 
are often in the field would be just as good. In the Caribbean Cliona 
delitrix needs to be included, and maybe Pione lampa. Anyone interested?

Cheers, Christine


On Tuesday, October 17, 2006, at 04:48 , Gregor Hodgson wrote:

> Mike has long suggested the use of boring sponges as a useful/simple
> technique for estimating one component of reef health. We are always 
> open to
> good suggestions and this idea is appealing, however, our initial tests 
> did
> not support the theory. To be useful to us, this indicator needs to 
> work at
> least regionally if not globally. But we have not given it a rigorous 
> test.
>
> We would be very pleased if Mike (or supporter) would suggest a 
> volunteer
> level protocol and then if teams around the world might give it a test 
> to
> see if it holds up as an indicator on a wide geographic scale.
>
> Best,
> Greg
>
> Gregor Hodgson, PhD
> Executive Director, Reef Check Foundation
> P.O. Box 1057 (mail)
> 17575 Pacific Coast Highway (Fedex)
> Pacific Palisades, CA 90272-1057
> Tel: +1-310-230-2371 Fax: +1-310-230-2376
> email: gregorh at reefcheck.org
> www.ReefCheck.org
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Dr. Christine Schoenberg

Carl von Ossietzky Universitaet Oldenburg
Fakultaet 5
Institut fuer Biologie und Umweltwissenschaften
AG Zoosystematik und Morphologie
26111 Oldenburg
Germany
ph +49 (0)441 798 3611
fax +49 (0)441 798 3250

(alternative email:  christineaway at gmx.net )