Sea Tigers, Horses, Snakes, Slugs, Cats – How's that for Biodiversity?!

May 29, 2012

With Saturday spent at Singapore’s first Biodiversity Festival at the Botanical Gardens, Hantu Blog volunteers spent Sunday doing what they do best – finding more stuff out on the reef, so we can tell everyone else about it! And boy did they make some findings! The day began even before the divers went underwater, with the encounter of the Yellow-lipped seakrait (above) creeping down from a coral encrusted pillar. Divers were ecstatic! But they weren’t about to get too close. Laticauda colubrina is a highly venomous sea snake and one should avoid handling it. That said, this snake is not known to attack if left alone and unprovoked, it is also very unlikely that one gets bitten by it firmly enough to have venom injected because it is back-fanged (intended more for fish than large mammals). If one should get bit by a Yellow-lipped seasnake, the first symptom is the rapid breakdown of skeletal muscle tissue. While we’re out at sea, we certainly don’t have the facilities to replace your thumb should it dissolve away, so these snakes are best left alone.

From the fearsome to the fragile. Above: Reliable chromodoris (Chromodoris fidelis)

Seasnakes above and Snakey bornellas (Bornella anguilla) underwater! Watch a video of it feeding!

Although it is called a Slender ceratosoma (Ceratosoma gracillimum), this one doesn’t look quite so slender. It’s possible that it just devoured another seaslug. When I saw this picture, couldn’t help but think about the sea slug plushie that Ria Tan made while we were at the Biodiversity Festival…

Don’t you think this plushie looks just like the Slender ceratosoma above?! This one looks fat because it just ate another nudibranch, so perhaps the ceratosoma just had a bite too!

This real close encounter with a Fan-bellied filefish (Monacanthus chinensis) lets us appreciate the gorgeous neon blue spots it’s got on the flap of its belly!

Glossodoris atromarginata on a crinoid.

While the dives certainly started off on a high, divers certainly felt a little despondent when they encountered three shark carcasses on the reef. This carcass was getting picked on by a Red egg crab (Atergatis integerrimus). We don’t know for sure what killed the sharks, but two of the carcasses had mouths ripped, which may suggest they were caught with a hook and either managed to break away from the hook, though not without sustaining an injury that killed them later. They might also have been pulled up by fishermen who decided to throw them back to sea, not knowing that the sharks were injured beyond recovery.

The second shark carcass.

The third shark carcass with a metal rod placed next to it for scale. The sharks have been identified as Brown-banded cat sharks Chiloscyllium punctatum, is a bamboo shark in the family Hemiscylliidae. When young, these sharks have prominent dark bands, and as they mature, they lose their bands to acquire a grey coloration. Between the phases, it has spots, similar to those in the pictures above.

Much to everyone’s delight, a fourth and living Brown-banded cat shark was encountered later in the dive!

Other cool encounters included this Arrowhead spider crab (?) that was elaborately adorned with hydroids! You can see its pincers in this picture, can you figure out where its head is?

There were also loads of beautiful nudibranches.

A pair of Chromodoris cinta.

A pair of Hypselodoris emmae.

Tigertail seahorses (Hippocampus comes) are always a welcome encounter on the reef. It was good to see them again after not having seen them for a few months. Good to know they are still on the reef. Volunteers have on a few occasions been approached by collectors and fishermen to inquire about seahorses. Evidently, there is still a demand for them from the aquarium/ornamental fish trade.

Rubble pipefish (Corythoichthys sp.)

Lots more was encountered on the reef over the weekend, but the find that definitely took the cake for all divers this weekend has got to be the Spiny Tiger Shrimp (Phyllognathia ceratophthalmus). This is the first time that this shrimp has been encountered at Pulau Hantu and our divers were simply thrilled! This shrimp has many common names throughout its range (Harlequin Shrimps, Tiger Shrimp, Bumblebee Shrimp, Horned Bumblebee Shrimp, Bongo Bumblebee Shrimp, Bongo Shrimp and Dragon Shrimp). They can be found on sponges and algae of coral and rocky reefs, and now, Pulau Hantu 🙂

 

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