[Coral-List] Black cyanobacterisponge, Terpios hishinota, outbreak in, coral reefs and geographic information needed (Allen Chen)

[William Allison]

Re. Terpios and Corallimorphs in Maldives.

I have noticed a few patches of what I think may be Terpios in Baa Atoll. My
impression was that it was growing on dead corals and rubble and especially
in disturbed areas. It is relatively rare throughout Maldives and shows up
on few of my surveys.

Quantitative surveys indicate no increase in Palythoa cover and decrease in
corallimorpharian cover despite the low mortality of both in 1998, and the
subsequent liberation of physical space because of coral mortality.

Stimulated by chicken little alarms about "killer anemones" (i.e.,
corallimorpharian) based on point in time observations of localized patches
in the early 1990's I have monitored them carefully in many locations in
Maldives. Although they did dominate some (often physically degraded) reefs
prior to 1998 they did not seem to be spreading. They did not suffer
appreciable direct mortality in 1998, and contrary to my expectations,
mortality increased post-1998 and a number of patches disappeared. Increased
predation was observed and probably contributed to the observed changes.

Bill


On Thu, Feb 19, 2009 at 3:06 AM, Thomas Le Berre <thomas at seamarc.com> wrote:

> Dear Allen,
>
> We also have lots of Terpios in the Maldives, and I find it quite
> alarming. I have seen it in 2005 in some places, but a lot in Baa Atoll
> in June. They tend to be more abundant in reefs with a better coral
> cover, and usually more developed on the parts of the reef where the
> current is going along the reef. Typically, the main forcings (currents
> and winds) are in the east-west direction here, and they will colonized
> more the northern and southern sides of the reef. This could be linked
> to the way they propagate or alternatively they may also require calmer
> conditions to spread. They look strong and will spread on many different
> species of corals, covering almost entirely large patches.
> This could also be related, we have other types of invasions by
> zoanthids (Z. mantoni), which does not seem to actually kill the corals,
> but probably hinders coral recruitment, and corallimorphs (Discosoma
> sp.), which kills some species of corals.These would probably have
> colonized dead areas after the 1998 bleaching, whereas the Terpios seems
> more abundant on the reefs that are recovering the best (again, in Baa
> atoll). It seems important to have a better look into this.
>
> Cheers,
>
> Thomas Le Berre
> Managing Director
> Seamarc Pvt Ltd
> M. Maya, Gandhakoali Magu
> Male', Rep of Maldives
> www.reefscapers.com
>
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