Barnacles may seem harmless, but there are some that are insidious parasites of crabs! These gruesome parasites creep into the crab, living on it and hijacking the crab into producing their eggs!
Here's one victim of the parasitic barnacle! How do we know this?
Because of the parasite egg sacs emerging from the crab. The
parasitic barnacle (
Thompsonia sp.) grows through the body of the host crab like a root system. The parasite affects the crab's reproductive system such that the crab becomes infertile. The parasitic barnacle eventually produces tiny egg sacs that emerge through the crab's joints. Exhausted by the barnacle, parasitised crabs usually come to an unhappy end. Thank goodness these barnacles don't infest humans!
Changi has nice stretches of seagrasses, home to all kinds of intriguing animals.
The seagrasses are dotted with many colourful creatures. As usual, there were lots of
Thorny sea cucumber (
Colochirus quadrangularis), and many small carpet anemones some of which might be
Tiny carpet anemones (
Stichodactyla tapetum) while others might be
Haddon's carpet anemones (
Stichodactyla haddoni).
Also abundant today were
Gong-gong snails (
Strombus turturella),
Window pane clams (
Placuna sp.) of all sizes, and small to medium sized
Fan clams (Family Pinnidae).
There were also many
Swimming anemones (
Boloceroides mcmurrichi), which do kind of look like seaweeds and can be overlooked. Buried in the sand were a few
Peachia anemone (
Peachia sp.), all with white body columns. I didn't see any other kinds of sea anemones today. I saw some
sea pencils and a few
cerianthids (Order Ceriantharia).
Here's another carpet anemone with sea cucumber in the midst of the seagrass meadow.
I continue to see many T-shaped
hammer clams (
Malleus sp.) here. These animals are bivalves, the hinge is on the T-shaped part. This one had a chiton on it!
The
chiton is also a mollusc! This is more obvious when we look at the underside. Like many snails, it has a broad foot.
I found the empty shell of a
Watering pot shell (
Verpa penis) which was originally thought to be extinct in Singapore. Marcus later found another empty shell. Looks like they are still very much alive on Changi!
This strange animal is not a worm. It is actually a mollusc and actually a bivalve or clam. There are two tiny oval shapes which are all that remains of the two valves of this strange bivalve.
While I saw some
Cake sand dollars (
Arachnoides placenta), I didn't come across any
Pink sand dollar (
Peronella lesueuri) today, except one dead one. I thought I saw some
White sea urchin (
Salmacis sp.) in deeper water, but I didn't see any on the higher shore. Strangely, neither Marcus or I saw any sea stars. We also did see any seahorses.
Today the tide wasn't very low and was late, i.e., at sunrise. So perhaps this is why we didn't see as many animals as we did
earlier this month.
Some parts of the seagrass meadows were covered in a layer of brown scummy growths. But the seagrasses seem generally alright. There seems to me to be a lot of
Needle seagrass (
Halodule sp.), almost as much as the
Spoon seagrasses (
Halophila ovalis). The
Fern seagrasses (
Halophila spinulosa) was sparse today.
Today we didn't come across any driftnets as we did on
our previous trip here. I hope the shore keeps well until we get a chance to visit it again.
