Tuesday, 26 June 2007

Slug frenzy @ P.Satumu

After Sat's dive, have found *yet* another group of tiny critters for me to practise my underwater phototaking (I usual target nudibranchs and crinoids/feather stars). And during yesterday's dive, I WAS trying to look for stuff amongst the whips and seafans (sorry Diana, was supposed to be recruit spotting for you! *heh*) but no such luck. Guess the portion of the reef slope we were at just didn't have enough seafans or whip corals (they weren't as stunning as the Kusu ones, and many had algae and ascidians covering ~20% of the colony).

With my guilty conscience kicking in, stopped looking at the gorgonians and started looking at rubble etc for coral recruits. Good news is that many of the recruits (possibly some of those from the mass spawning in April) are growing quite nicely on big rocks and consolidated substrate. No danger of them being swept away or rolled over etc. This one looks like a relatively young mushroom coral (they start out similarly to other hard corals, attached to a substrate, before becoming the free-living adult form)

The not-so-good news is that our Honors kids need recruits for their projects on reef remediation methods....

So amidst the recruit hunting, found loads of Phyllids and blue dragons. Managed to *finally* get that nicely focused shot of the rather commonly seen blue dragons. *yay*

Blue dragons aka Pteraeolidia ianthina

Even a juvenile one here that was around 5mm long!!!

And of course, there was this couple of Cuthona sibogae near where we descended. ^^ This is one of the more colorful and eyecatching of the nudibranchs that I see in Singapore. Wonder if that means that they are more poisonous that say the Phyllids that are generally more drab... The orange hydroid that these two are on seems like Sertularella quadridens, so I wonder if they were feeding or mating, or perhaps doing a little of both?

The nudis weren't the only sea slugs that were out and about yesterday. Towards the end of the dive, I even spotted a nice little sapsucker (Thuridilla bayeri). Sap0sucking slugs are sea slugs like nudibranchs but these are generally herbivorous (aka vegetarian), feeding on green algae. This is probably the main reason why a number of the sap suckers (e.g. Elysia sp.) are green. The nudibranch book (Nudibranchs and Sea Snails: Indo-Pacific Field Guide by Helmut Debelius) I have on hand says that "little is known about the feeding habits of this genus", so I don't know how this pattern/coloration helps this little slug. Interestingly enough, the sea slug forum puts this individual as T.gracilis and may be considered synonymous with T.bayeri.

Links to the Seaslug forum articles below:
(1) Thuridilla gracilis
(2) Thuridilla bayeri
(3) Comparison of T.gracilis & T.bayeri

1 comment:

Siyang said...

Back fr Tioman lao right? Waiting for ur post and pictures! Quick quick =)