22 July 2012

Sharks and tiny critters on Cyrene

A small team lands well before dawn, for one of the last night trips to Cyrene for the year.
Sharks were seen! By the rest of the team. I saw mainly tiny creatures, which are fascinating too!

One of the curious creatures I saw were these tiny ctenaphores on a huge leathery soft coral. These are not flatworms but belong to the Phylum Ctenaphora and can produce very long fine tentacles for filter feeding. They blend perfectly on their leathery coral host! Nicholas Yap shared more about them (I need to start a wild fact sheet on these little critters).
Here's a closer look at the big leathery soft coral (Family Alcyoniidae) that they were on, and at one of the little beasts and the fine nets of tentacles that they produce.
In fact, there are all kinds of tiny things living on hard corals too. Each brown spot is an Acoel flatworm (Acoela) on this Small goniopora coral (Goniopora sp.).
I saw several different kinds of flatworms: the Spotted black flatworm (Acanthozoon sp.) and a Starry flatworm (Pseudobiceros stellae). I only saw the Jorunna funebris nudibranch but the rest of the team found lots more.
I checked under rocks today and found lots of little crabs, snails and clams. As well as these pretty brittle stars. Marcus also found the rarely seen Bodaschia sea cucumber (Bodaschia vitensis) which spewed sticky strings on him. I got some on my fingers too, and they were really hard to remove. So far, we've only seen this sea cucumber on Cyrene Reef.
Marcus also found one of the specials of the day: a Banded mantis shrimp (Lysiosquilla sp.). We don't see this very often. These superb predators have a Swiss Army knife of strange implements on the underside to capture and eat their prey. This one, though, seems to have lost its raptorial pincers?
Kok Sheng found this strange moon snail with a white body and a white and orange shell. Is it a young Eggwhite moon snail (Polinices albumen)?
I also found a Spurred turban snail (Astralium calcar) and found out that it has a pretty striped body and striped tentacles!
Today, I also took a closer look at the tiny parasitic snails (probably Family Pyramidellidae) that infest the many Common sea stars (Archaster typicus) found on Cyrene. While most are found on top of the sea star, some are wedged in their 'arm pits', in between the arms. I think there might be more than one kind of these snails that suck on the body fluids of the sea stars. Some of the tiny ones floated on the water surface when they are dislodged from the sea star, several forming 'rafts'.
I also checked the big Knobbly sea stars (Protoreaster nodosus) for parasites and found none. But I did see this fish hiding next to a Knobbly!
There were lots of little octopuses out and about in the dark when we first arrived. I had fun looking at them in the high water.
Some of the octopuses slunk away, others hunkered down and pretended to be a rock. Even after sunrise, I spotted more out and about on the shore.
Today, I'm trying out the new intertidal survey method on the reefy part of Cyrene. There are some huge corals here! On the horizon are the massive industries on Jurong Island.
There are also many leathery soft corals (Family Alcyoniidae), though most are rather fragmented and small. None that I saw were bleaching.
There were many Pore coral (Porites sp.) and as usual, an abundance of Favid corals (Family Faviidae). None of those I saw were bleaching. Although Pei Yan saw one large bleaching coral elsewhere on Cyrene.
This stretch of shore has some colourful hard and soft corals. Most of the flowery soft corals (Family Nephtheidae) I saw were purple, a normal healthy colour. Some of the special corals I saw included Brain corals (Family Mussidae), Cauliflower corals (Pocillopora sp.), Disk corals (Turbinaria sp.) Anemone coral (Goniopora sp.). There were also several Flowery disk corals (Turbinaria sp.). None of those I saw were bleaching, although some of the Small gonipora corals (Goniopora sp.) were rather yellowish.
I was glad to see this large Brain anchor coral (Euphyllia ancora) that seemed healthy and unbleached. These were among the first to bleach during the mass coral bleaching event in 2010.
Here's a slide show of the survey that I did today. There sure is a lot of life on Cyrene's reefy shores.
The tide was very high when we arrive, only the very top of the sand bar is exposed. A huge cloud of emissions hang over the refineries on Pulau Bukom.
High tide is a great time to spot sharks on Cyrene! Russel spotted several. We stayed until the tide was high again, and we spotted more sharks coming in to feed with the rising tide: Marcus and Pei Yan are pointing to the sharks in this photo. As Russel said, Cyrene can be considered shark 'infested'!
Sadly, the first time I saw sharks at Cyrene, they were trapped in a driftnet in Jul 2010. This event spurred me to start Project Driftnet and the shark found dead on Cyrene is on the banner of the Project blog. Ivan also released a shark from a fish trap in Aug 2011. Today, Russel and Pei Yan saw a large fish trap on Cyrene.
We do often see sharks on Cyrene especially in high water as we did in Mar 2011 and Nov 2011. We also often come across shark egg capsules on Cyrene.

It's amazing that such wonderful marine life abound on a submerged reef in the middle of the industrial triangle!

I'll be back on Cyrene on Tuesday with another team from the Maritime Port Authority. I'm also excited about the workshop on bivalves next week.

So much to see and do for our shores!

Posts by others on this trip
  • Russel on facebook with sharks, sea stars feeding and more.
  • Pei Yan with lots of special snails.

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