12 July 2009

Special anemones of Kusu Island

Kusu Island is teeming with large anemones! In particular, it is a magnificent place to see the Magnificent anemone (Heteractis magnifica).
Clusters of many of these large sea anemones are found on this reef, just minutes from the city centre. The only other place this anemone is commonly seen is Pulau Hantu. A few individuals are also sometimes seen at Pulau Semakau.

Here's a look at the cluster of anemones. Alas, the water at Kusu Island is seldom clear. Sadly too, today none of us saw any anemonefishes in these large sea anemones. In the past, False clown anemonefishes (Amphiprion ocellaris) have been seen in these anemones. Marcus did see an anemone shrimp in one.
Here's another Magnificent anemone, which has settled on a living hard coral, unfortunately killing off parts of the hard coral.
Another Magnificent anemone has settled on the seawall and is hanging until the tide rises again.
A special anemone seen on the shore today is the Fire anemone (Actinodendron sp.).
As its common name suggests, it packs a powerful sting! We've only seen this anemone thus far on Beting Bronok, Pulau Semakau and Terumbu Raya.

There were also lots of Giant carpet anemones (Stichodactyla gigantea) on the shore. And on Kusu, they ARE often quite large. Many are snuggled up next to hard corals. Alas, we didn't see any anemonefishes or even anemone shrimps in these either.
Kusu does not have as many Frilly sea anemones (Phymanthus sp.) nor in as wide variety as some other shores. But the team remarked that those seen on Kusu were particularly large.
Also abundant on the sandier areas among the tiny Spoon seagrasses (Halophia ovalis) were Haddon's carpet anemones (Stichodactyla haddoni) in various colours.
I saw one that was a pale sickly yellow. Is it ill? If so, why?
While I was focusing on the little fanworms in the soft silty areas, I accidentaly photographed a tiny little sea anemone.
Chay Hoon also saw one Peachia anemone (Peachia sp.) and a wriggly star anemone.

I had a quick look at another part of Kusu Island that is carpeted with zoanthids. Also called colonial anemones (Order Zoanthidea), they are not true sea anemones (Order Actiniaria).
But they sure are pretty! All the major kinds of zoanthids seen on our shores can be seen on this small stretch at Kusu Island.Today, we started our trip under ominous skies. Huge dark clouds and sheets of rain were pouring down on the city. Fortunately, we were spared wet weather and had a cool day on the shore.
Hard corals have started creeping back into the big swimming lagoon that was created on Kusu Island by building seawalls on an original reef flat. Many hard coral colonies are somewhat large and fan worms and other animals have settled in among them too.
Hard corals form encrusted areas in some parts of the lagoon.
With many different kinds of corals crammed together.
Boulder-shaped favid corals (Family Faviidae) in various colours are quite common here.
Sand seems to be accumulating in the area where the corals are, and the sand is sticky with silt. While most of the corals seem somewhat ok, I saw two hard corals with grey icky squishy stuff on parts of the colony. I'm not sure if this means that they are unwell.
There were also several large leathery soft corals (Family Alcyoniidae), including this one with a pimply texture on the leathery common tissue. My first record for Kusu Island. Probably I just missed noting it in my previous trips.
Another first for me is seeing these Cake sand dollars (Arachnoides placenta) on the sandier stretches. These sand dollars are quite commonly seen on many of our shores. While we saw the Laganum sand dollar (Laganum depressum) on Seringat Kias which lies just across from Kusu, we didn't see any on Kusu.
There were also some Common sea stars (Archaster typicus) which only came out of hiding from the sand with the incoming tide. And I saw one lonely Garlic bread sea cucumber (Holothuria scabra).

These shells of special snails are intriguing! The larger one is of a Bonnet snail (Family Cassidae) and the smaller, probably a Frog snail (Bufonaria sp.). Would have been nice to see living specimens of these snails! Both these shells were occupied by hermit crabs. So please don't take any empty shells home, even broken ones! The rest of the team saw a Spotted hermit crab (Dardanus sp.) near the reefy part of the shore.
Another intriguing snail was this conch snail with a thin lip. Is it a young Gong-gong (Strombus canarium) or something else?
This, however, is clearly the Black-lipped conch (Strombus urceus). Kusu Island is one of the few places where they are quite abundant. Although they are hard to spot as the shell is usually well encrusted with camouflaging organisms.
There were also a lot of Oval moon snails (Polinices mammatus) prowling the soft sandy shores. But we didn't see the other kinds of moon snails that we saw on Seringat-Kias.

I also saw an Orange fiddler crab (Uca vocans) with bright red parts on its legs!
This pretty Slender-lined shrimp-goby (Cryptocentrus leptocephalus) was stuck in a shallow pool at low tide and obviously lost its shrimpy friend. It seemed to have tried to burrow in by itself and gotten stuck.
We placed it in a bigger pool. You can see how long and elegant the fish is! So far, I've only seen this fish at Kusu Island (here it is with its shrimpy friend on my last visit to Kusu) and Pulau Semakau.
The rest of the team saw lots of other interesting fishes and other creatures. But not a single nudibranch or even slug! This is perplexing.

There's a lot of marine life to discover on Kusu Island! Though you have to take a close look in order to find many of them.
The shores at Kusu were a little quiet today. And the sandy lagoon seemed to have become more silty and thick with seaweeds in some parts. Kusu Island has other reefy parts and another large lagoon, which the tides and time did not permit us to explore today.

In fact, we found all the other shores we visited in the last few days to be quiet too. Perhaps it is because of the full moon? There's a lot more that we have yet to learn about our shores!

Other posts about this trip

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