Sunday, August 29, 2010

Semakau Walk on 28 Aug 2010

I had been sick for the past few days, and thus originally was thinking of giving this trip a miss. However, the fever finally stabilised by Friday afternoon, and I decided to go ahead with it. LK still did the main coordination work though, while I helped out with the hunting-seeking at the beginning, before heading out in search of shrimps for our shrimp workshop later in the afternoon.

I did not take many photos for this trip, so the organisms highlighted here were just some of the many things we saw that day.

Dragonfish Sea Cucumbers (Stichopus horrens) were really abundant today. I easily saw at least 10 of them even before I crossed the seagrass meadow. Some of them were really well-camouflaged among the sponges and silt-covered rocks.

I found this Cushion Star (Culcita novaeguineae) in the seagrass meadow. In fact, the other hunter-seekers found 2 more Cushion Stars later during the trip. This sea star got its common name from its cushion-like appearance, but it is certainly not soft and cuddly like a cushion. It feeds on corals.

The Sandfish Sea Cucumbers (Holothuria scabra) usually burrow in the sand, though on Semakau they are often seen on the surface as well.

LK spotted a net in the seagrass meadow with many dead animals. Unfortunately, Semakau is still not a protected area, and hence we often have fishermen coming here to set up nets and traps. This fish didn't look familiar, and I decided to flip it over to a better look.

It turned out to be a Remora (Echeneis sp.)! While I had seen remoras while diving in other countries, this was my first time seeing it in Singapore! This fish has a sucker plate on its head, which it uses to attach itself to bigger animals like sharks, rays or whales. The presence of this rather big remora (more than 30cm long) means there must be animals big enough for it to attach itself to! The relationship with the remora and its host is said to one of commensalism - meaning one party benefits while the other doesn't gain or lose much. The remora hence gets a free ride, and some species are said to feed on the leftovers food of the host, or even the host's feces.

There were many Giant Carpet Anemones (Stichodactyla gigantea) among the seagrasses, and this one has a small little anemonefish in it.

Most of the Sand-sifting Sea Stars (Archaster typicus) were paired up, performing pseudocopulation. The one on top is the male. They usually pair up up to 2 months before releasing their sperms and eggs into the surrounding water when tide is high.

Helen found 2 Noble Volutes (Cymbiola nobilis), and this was the smaller one she found. This huge snail feeds on smaller snails and clams by holding them in its muscular foot to try suffocate them.

The tide was rather high and hence we did not managed to go too far out to the reef area or even the outer edge of the coral rubble area. At the edge of the water, I found was this Stonefish Sea Cucumber (Actinopyga lecanora), looking just like a piece of well-eroded stone among the rocks in a tidal pool.

While heading back in the seagrass meadow, I found this Gafrarium pectinatum, a species of Venus Clam (Family Veneridae). Was quite glad to find this as while a few of the other volunteers and colleagues have seen this on Semakau, this was my first time seeing this species here. Unlike the similar-looking species, Gafrarium tumidum, which is rather common on Semakau, Gafrarium pectinatum appeared to be less commonly seen.

The walk soon ended, and I was really glad that the weather was perfect - cloudy, windy and not too hot, certainly a nice closure for our last Semakau walk of the year!

Wednesday, August 11, 2010

Sentosa's Tanjong Rimau

Visited Sentosa's Tanjong Rimau few times recently, so this is just a summary blog of the things I saw. Unknown to many Singaporeans, Sentosa has a natural underwater world not too far away from its man-made underwater world! :)

Tiny little Costasiella Sea Slug (Costasiella sp.) less than 5mm long that was found on the Fan Seaweed (Avrainvillea sp.). They were rather numerous, and on of of the seaweed, I actually found about 10 of them.

When I told KS that I was going to Sentosa, he commented that CH found a Galloping Sand Star (Stellaster equestris) some time back, and I might see one. I told him that my luck had not been fantastic these days, so I doubt I would see one. But surprise surprise! Thanks to his golden mouth, I really saw one this morning! While I have seen this before at Semakau, it's still really nice to see it again here on Sentosa :)

Hen spotted a juvenile Cushion Star (Culcita novaeguineae) - my first time seeing it here on Sentosa too!

At the sandier area, there were lots of Sand Dollars (Arachnoides placenta).

Since we reached the shore while it was still dark, there were lots of nocturnal animals, such as the many shrimps in the various tidal pools.

The crabs were out too, and the various species of swimming crabs (Family Portunidae) were the most numerous. This is probably a Thalamita pelsarti.

There were many juvenile swimming crabs too.

Among the branching Montipora corals, there were several Smooth Spooner Crabs (Etisus laevimanus). These crabs use their claw's flattened tips to scrape algae to feed on.

A few Purple Climber Crabs (Metopograpsus sp.) were seen crawling over the rocks. They have claw-like legs which aid them in their climbing.

There were many tiny hermit crabs, which I have no idea what species they are.

There was this little Estuarine Moray (Gymnothorax tile) slithering around, probably searching for smaller animals to feed on.

On one of the trips, we saw a black frogfish! My guess is that it is a Spotted-tail Frogfish (Lophiocharon trisignatus) in its black phase.

Moving on to the sessile animals, I saw a number of sponges appearing rather sick, and probably dying or dead... They turned greyish-black in colour, and appeared to be disintegrating.

Some of the corals had a rather sickly colour too.

There were a number of bleached corals here and there, but guess there's little we can do about such a situation except to blog and spread awareness.

Most of the corals appear rather healthy though, such as the Turban Coral (Turbinaria sp.) above.

There were a few colonies of Acropora corals, and I was rather surprised to see them as the water was really murky, and Acropora mostly require clear and pristine water to do well.

There were a number of interesting plants at Tanjong Rimau too, such as this Raffles' Pitcher-Plant (Nepenthes rafflesiana).

There were at least 3 locally critically endangered Xylocarpus rumphii at Tanjong Rimau. On mainland Singapore, I have only seen naturally occurring ones at Sungei Buloh, though I understand they can also be found at Pandan Mangrove. Offshore, apart from Sentosa, they can also be found on St John's Island.

Apart from the wildlife, Tanjong Rimau also has majestic cliffs to offer!

There were quite a few natural caves too!

So apart from being a nice place to show biology students about our marine life, it is also a great place for geography students to learn about coastal landforms :P

Tuesday, August 10, 2010

Changi Beach on 10 Aug 2010

Readers of my blog might have noticed that I had been blogging a lot less frequently these days. I am still visiting our shores regularly, but just that I have been so busy with work these days, that I really had no time to blog about most of my trips.

But since it has been a while since I last visited Changi Beach, and we saw quite a number of interesting stuff today, I decided to just do a quick listing of the highlights that we saw, just to share with my friends out there who read my blog regularly :)

There were lots of brittle stars on the sandy shore, many of them stranded on dry sand. These brittle stars are rather common on our northern shores, though they usually burrow into the sand in the day.

Near the rocky area, we found a Rock Stars (Asterina coronata). We decided not to spend too much time search for stuff here, since we can usually find more things at the sandy area.

There were several Biscuit Sea Stars (Goniodiscaster scaber), though certainly not as abundant as previously. There were a number of rather huge ones bigger than my palm.

There were a number of Cake Sea Stars (Anthenea aspera) too, but I did not see the really huge ones. This one was about 7 or 8 cm wide.

We saw many of these small sea star, which looked like they could be juvenile Biscuit or Cake Sea Stars.

There were significantly fewer Sand Stars (Astropecten spp.). I saw a few plain ones, like the one above...

and 2 or 3 of the more colourful ones.

Several species of sea cucumbers were spotted, and I'll just highlight a few here. This little sea cucumber is rather abundant, but I have no idea what species this is.

This is yet another unknown sea cucumber, which I have seen on both our northern and southern shores.

There are two sea cucumbers here. Can you spot them?

Ball Sea Cucumbers (Phyllophorus sp.) were really abundant here, and I could see some of their feeding tentacles in the shallow pools.

The little black sea urchins (Temnopleurus sp.) appeared to be in season, and I saw hundreds of them clustering together.

Also clustering were these snails, which look like some kind of murex (family muricidae).

Among the snails I saw a few Orange Striped Hermit Crabs (Clibanarius infraspinatus).

Paguristes longirostris
Understand that CH had seen this hermit crab previously, but this was my first time seeing this. Hopefully our hermit crab expert, Yoyo, will be able to help identify this soon. (Update: This is Paguristes longirostris. Thanks Yoyo for the ID!)

There were several other hermit crabs around which I do not know the species.

I saw 2 Noble Volutes (Cymbiola nobilis), prowling around, probably search for clams to feed on.

I was rather glad to find quite a few Miliaris Cowrie (Cypraea miliaris).

Here are 2 of them. Not sure if they were doing anything sexy.

There were a few Hairy Sea Hares (Bursatella leachii), though they appeared somewhat off-coloured.

And also, a few Geographic Sea Hare (Syphonata geographica). These sea slugs burrow, so they could be a lot more abundant than they appear.

I also found a few cockles (family Cardiidae).

There was a Scorpionfish among the sea urchins.

I found many Pipefish, but did not have the luck to find any seahorses this time round.

Somehow, I thought there were a lot more Tube Anemones compared to my last trip.

Could this small carpet anemone be a Stichodactyla tapetum?

There were a few really tiny sea anemones on the seaweed.

This one had lots of red spots on it.

There were several Swimming Anemones (Boloceroides mcmurrichii), and this one attached itself to a solitary ascidian (Polycarpa sp.).

There were a few sea pens half-burrowed into the sand too.

All in all, it was great to be back here. Certainly hope I will have more time to properly blog the next time I am here though :P