30 August 2008

Kusu Quickly: with snappy encounters

4am and we're off. It wasn't very low, but our last chance for a predawn visit to Kusu Island this year.And among the first sightings we made was this pair of snapping shrimp and shrimp goby that we've not seen before!

The shrimp goby is very pretty! And the snapping shrimp is not among the ones we commonly see. Wow! So we have no idea what they are.

The shrimp goby is a fish (Family Gobiidae) that lives in the same burrow with a snapping shrimp (Family Alpheidae). With keener eyesight, the goby keeps a look-out while the shrimp busily digs out and maintains their shared home. The shrimp is literally constantly in touch with the goby with at least one of its antennae always on the goby. When the goby darts into the burrow, the shrimp is right behind it!

Kusu Island is also one of the many Southern Islands where you can see the False clown anemonefish (Amphiprion ocellaris). Today, only one of the Giant carpet anemone (Stichodactyla gigantea) that I saw had these fishes.There were two of these fishes! How nice. Usually, the bigger one is the female, while the male is smaller. Sometimes there are several small males together with one big female in one sea anemone. These fishes can change sex. If something untoward were to happen to the female and she dies, the biggest male will change into a female!This sea anemone with 'Nemos' also had a pair of anemone shrimps! The transparent anemone shrimps with five spots on the tail (Periclimenes brevicarpalis) were also seen on several of the Haddon's carpet anemones (Stichodactyla haddoni) at Kusu. These anemones have shorter tentacles and are found in the sandy lagoons away from the reefs. Anemone shrimps are often seen in a pair of male (more transparent) and female (with white spots on the body).Sea anemones eat fishes, as was evident in this photo. The poor fish swam suddenly into the sea anemone which immediately closed up over the victim. I hardly had time to take this photo before the fish disappeared in the folds of the large sea anemone. So it's really amazing that the clown anemonefish and anemone shrimps can live on these sea anemones.The shores were teeming with all kinds of fishes this morning. But often you had to look carefully as some are small and very well camouflaged.
The Painted scorpionfish (Parascorpaena picta) is large but also well camouflaged!Others may look similar at first glance. The fish on the left is the Tropical silverside (Atherinomorus duodecimalis), while the one on the right is a halfbeak (Family Hemiramphidae).
There was also a very large blue fish that looked like a halfbeak.There were also several Kite butterflyfishes (Parachaetodon ocellatus) in the lagoon today. Ivan also saw some Copperbanded butterflyfishes (Chelmon rostratus).And lots of these fishes, which are probably Perchlets (Family Chandidae), I'm not too sure.
Of course, Kusu Island has living reefs, and lots of various hard corals. My special encounter today was with this large and very happy looking Brain anchor coral (Euphyllia ancora) which so far I've only seen on St. John's Island and Raffles Lighthouse. Euphyllia species generally have long tentacles, some with U-shaped tips. Euphyllia ancora is distinguished by the brain-like pattern of the hard skeleton.Living corals provide shelter and food for a wide range of marine life. Such as flatworms like this Pseudobiceros bedfordi. I do not see this flatworm often so it was nice to see it again.Octopuses are commonly seen on our shores, but today at Kusu, I only saw this small one. It was really getting busy with all its arms stretched out, to check out various crevices all at the same time!As I took a photo of this stranded cuttlefish, its body patterns pulsed a bit. So I thought it was still alive and put it gently into the water. But it was dead. Ivan says these animals generally die after they mate and lay eggs. So perhaps it was just its time to go.And what a lovely surprise, a large red feather star (Class Crinoidea)! Crinoids are sometimes seen on the intertidal, but they appear to be rather seasonal.

Other echinoderms seen on Kusu included lots of Garlic Bread sea cucumbers (Holothuria scabra), a few Long black sea cucumbers (Holothuria leucospilota) and Marcus saw a very special sea cucumber. There were also lots and lots and lots of Common sea stars (Archaster typicus).They were seen in both lagoons, and almost everyone of them were in mating position, with arms locked.All too soon, the tide turned and the sun rose. Here's a look at stars (on the shore) at sunrise.What a lovely shore, just overlooking our main business district, a 15-minute ride in a fast boat. City Reefs: this surely, is uniquely Singapore!
And the water is quite clear today! Even with the incoming tide, we could still see the reef and all kinds of large reef fishes coming back in with the tide. Chay Hoon hopes the vis will remain good for their dive tomorrow at Pulau Hantu with the Hantu Bloggers. That's another of our wild reefs popular with local divers.Alas, as the sun rose, things are not as clear for the skies. A haze was evident over the entire mainland.Which became even more obvious as we headed home.

We have been remiss in not visiting this interesting shore often enough in the year. Our last and only predawn visit to Kusu was in Jun with Dr James to look for zoanthids. And the zoanthids were still there in astounding variety.

It is disturbing that recently there has been talk again about developing this cluster of islands: Kusu, St. John's and possibly the Sisters. We should cherish this shore and hopefully, it will remain open to everyone to visit.

The Blue Water Volunteers conduct public walks on Kusu Island. Visit their website for more information.

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