05 February 2011

Snaily at Little Sisters

We're back on Little Sisters Island, which is tiny compared to its Big Sister.
We haven't been here since Jan 10!

Just as we arrived, it started to pour!!
Little Sisters lies just across from Big Sisters Island.
To wait out the rain, I thought I would have a quick look at the forested part of this tiny island. Wow, there's some stairs leading up the little hill. I never noticed this before. But it's locked and only authorised people are allowed to use it. I'm not sure what is up there.
Fortunately, after a little while, the rain stopped and the sun peeped out.
There's a little stretch of rocky shore here with lovely rock formations.
Behind the rocks, a small patch of coastal forest. The natural rocks are full of snails. Mostly Nerites (Family Neritidae).
There were also lots of Nerites on the artificial seawalls.
While these snails with ball-shaped shells may appear similar, a closer look reveals that there were several different kinds of Nerites on the shores. Here's more on how to distinguish among the Nerites commonly seen on our shores. The most abundant that I saw were Wave nerites (Nerita undata). There were also some Chamaleon nerites (Nerita chamaeleon) and near the low water mark, the limpet shaped Ox-tongue nerite (Nerita albicilla).
Top: Waved nerites, middle: Chamaleon nerites, bottom: Ox-tongue nerites
One of the little pools of water on the rocky shore was crowded with the little white egg capsules of Nerite snails!
Also common on the rocks were Drills (Family Muricidae), predatory snails that can drill a hole through the shells of barnacles and other shelled animals on the rocky shore. I saw lots of tiny Dark drills (Semiricinula fusca) with a dark shell opening and white foot. And several large spiny drills.
Left: Dark drills, right: Spiny drills
Also common were Turban snails (Family Turbinidae). There were many large Ribbed turban snails (Turbo intercostalis) with a rather pebbly texture to its 'door' or operculum. And some Dwarf turban snails (Turbo bruneus) which has finer pimples on its 'door'.
Left: Ribbed turban, right: Dwarf turban
I had a quick look under the stones and the animal I saw most often were scary bristleworms (Class Polychaeta). These worms can 'sting' painfully when their bristles penetrate skin. This is why we should be careful when looking under stones.
Like yesterday, I saw some of these strange pebbly crabs under the stones.
There were also some Broad zoanthids (Palythoa mutuki) and Sea mat zoanthids (Palythoa tuberculosa) growing on the rocks. These seemingly harmless animals contain powerful toxins to protect themselves. Another reason to be careful when handling rocks.
On the rocky shore was a Giant carpet anemone (Stichodactyla gigantea) with a little Long black sea cucumber (Holothuria leucospilota) under it! First time I've seen the sea cucumber hide under an anemone. Alas, no 'Nemo's or anemoneshrimps were living on this anemone. But Russel found a Haddon's carpet anemone (Stichodactyla haddoni) with enormous shrimps in it.
There is a wide reef around Little Sisters, here with Big Sisters on the horizon. But the water was quite high and rather murky so I couldn't really check the coral bleaching situation properly.
On the reef, Kok Sheng found a beautiful red feather star (Order Crinoidea)! He found many more, as well as all kinds of other interesting marine life.
I didn't get to see many hard corals because the tide wasn't very low. But those I saw seemed well and unbleached.
I saw a few Leathery soft corals (Family Alcyoniidae) and they were not bleaching.
I saw several Frilly sea anemones (Phymanthus sp.) on the rocky shores and one Peachia anemone (Peachia sp.) in the sandy lagoon. Unfortunately, we didn't manage to visit Little Sisters during the bleaching event last year. But all seems well now. More about coral bleaching on Bleach Watch Singapore.
There are two small sandy lagoons on Little Sisters. Here I saw one Black-lipped conch (Strombus urceus) and one Margined conch (Strombus marginatus sowerbyorum). I looked but didn't find any Common sea stars (Archaster typicus). Although we looked hard, we didn't come across the Clear sundial snail (Architectonica perspectiva) that we saw on our previous trip. James saw the Fluted giant clam (Tridacna squamosa) that we have seen here. I also saw a small patch of rather sad looking Tape seagrass (Enhalus acoroides), which was blooming.
Left: Black-lipped conch, right: Margined conch
As usual, our offshore islands have pretty Land hermit crabs (Coenobita sp.) on the high shore.
I missed the baby Yellow-lipped sea krait (Laticauda colubrina) that everyone else saw! See their blogs for more photos and stories. We should try to revisit Little Sisters at a lower tide!

As usual, Russel brought snacks for a very hungry team after the trip. Yumm. Thanks also to Chay Hoon, Russel, Kok Sheng, James and Ivan for contributions to the boat fare.

Other posts about this trip
  • Russel super fast post of sea snake, octopus, corals and more on facebook.
  • James with sea snake, giant clam and more
  • Kok Sheng with cave coral and more

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