Tuesday, June 7, 2016

Spongey comeback at Beting Bronok

Beting Bronok (BB) is one of our last northern reefs that is home to a wide variety of marine life that we don't see on our mainland shores. We only visit BB once a year to do our annual survey and noticed over the years that the reef is deteriorating.

BB is located off the north of Pulau Tekong and it is only exposed at a good low spring tide. Just right across the channel (Eastern Johor Straits) would be Pengarang, Johor. Today, we noticed that the sponges are making a comeback! You can see good growths of the colourful sponges in this landscape shot.

Here's a look at how BB was like in July 2008. Back then there were more sponges and the branching ones were doing very well.

Back to 2016, The growth in sponges have improved as compared to 2015. In fact, we noticed a lot more of the red Barrel sponges (Xestospongia testudinaria) starting to take root here.

Here's another look at how the Barrel sponge looks like before they become huge like barrels. The shapes range from fingers, hollow tubes to adult-like large vase shapes.

This collage shows the variety of colourful sponges that reside on BB. I hope they continue to do well as Chek Jawa and Pulau Sekudu are still not as sponge-filled as BB. It would be sad to lose this last stronghold.

How are the corals doing in this bleaching period? The Pink flowery soft corals (Dendronephthya sp.) and Ball flowery soft corals seem to be alright.

However, the Spiky flowery soft corals (Stereonephthya sp.) have bleached.

Here's how they look like from far. They have become a lot more conspicuous as they have been bleached. 

About 30% of the Boulder pore corals (Porites sp.) have been bleached. This is similar to my observation at Tanah Merah where this genus seems to be one of the firsts to be affected by thermal stress.

The other types of hard corals seem to be ok, such as this boulder-shaped coral.

Today we noticed an explosion of the Olive flatworms (Tytthosoceros lizardensis) as they are in season. This was the first moving animal that I saw after landing.

There were also many Black spotted flatworms (Acanthozoon sp.) and this particular one is super long!

Similar to last year, the Slender ceratosoma nudibranchs (Ceratosoma gracillimum) are common during the survey. These slugs tend to be spotted by divers.

Jianlin saw lots of these Blue dragon nudibranchs (Pteraeolidia ianthina). We never fail to be amazed by the electrifying blue colour on their body.

Chay Hoon lived up to her name by finding this super small blob that is actually a slug of some sort. We do not know its identity yet.

Today we saw the Bordered sea star (Craspidaster hesperus)! Here's how it looks like in-situ.

We came across a bountiful harvest of about 6 or more today! Here's 3 of them in one shot.

According to Dr Lane's "A Guide to Sea Stars and Other Echinoderms of Singapore", the arms of this sea star are bordered with a distinct series of wide marginal plates which themselves taper in size towards the ends of the arms. The upper surface consists of closely packed table-like paxillae crowned with short spinelets.

Sadly, the Knobbly sea stars (Protoreaster nodosus) that used to be found in higher numbers have either moved away or have died. Even at the lowest tide, I could only find one at the usual stretch. Later on, Nick found another one at an unusual spot. There are also the Spiny sea stars (Gymnanthenea laevis) and the Cake sea stars (Anthenea aspera).

This is my first time seeing the Long-spined black sea urchin (Diadema setosum) on BB, though it has been recorded here before.

Compared to previous years, we saw more Feather stars (Order Comatulida) on this trip!

Jianlin was hoping to see the Estuarine seahorses (Hippocampus kuda) and Jonathan found the first one. It's bright in yellow! 

And soon after, I found another one which is more speckled with black. I find the pattern really nice!

Another fishy surprise would be this Shortnosed boxfish (Rhynchostracion nasus). The boxfish has a strong and hard body shell. This species is likely to be able to secrete a powerful toxin on the skin (called ostracitoxin). This toxin is poisonous to other fishes and can even kill the boxfish itself if it is confined in an aquarium. Thus they are not recommended for aquariums.

This Thunder crab (Myomenippe hardwickii) was spotted to be holding on tightly to its new prey- the Blue-spotted fantail ray (Taeniura lymma)! Our first time seeing this crab snacking on the stingray.

Here's a mandatory shot of BB with Pengarang, Malaysia at its background. We will meet again in 2017!

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