Friday, August 7, 2015

How's Beting Bronok over two years?

Beting Bronok (BB) is one of the few remaining Singapore's northern reefs. Unfortunately, with each year that we visit, the diversity and abundance of marine life seem to drop. Nevertheless, what still remains on this special shore is still very much better than most of the other northern shores.

This post consists of what we saw over a span of 2 years from my previous trip in July 2014 (which I didn't blog) and our latest survey in Aug 2015- which gives us a rough comparison of the health of the shore over the span of 1 year.

BB is a submerged reef off the north of Pulau Tekong that is only exposed at a good low spring tide. Just right across the channel (Eastern Johor Straits) would be Pengarang, Johor. The view from BB is simply picturesque as you don't feel you are in Singapore at all.

On our trip back in July 2014, there were still lots of different types of Sponges (Phylum Porifera) of various shapes and colours that dot mainly the edge of the shore.

This anemone that looks slightly like blown glass is aptly named as the Glass anemone (Doflenia sp.). Though harmless-looking it may seem, this anemone is capable to horrible sting should you come into contact with it. One of our team mates suffered months of itch and inflammation when a tentacle struck her. 

There was also this Glass anemone-looking anemone that looks similar morphologically. Could it also be from the same genus of Doflenia?

Some of the uncommon sea anemones that are easily sighted on BB include the black and green versions of the Haeckel's anemone (Actinostephanus haeckeli). The Haeckel's anemones are also believed to sting badly.

A lovely find by one of the shore explorers would be this adult Three-spined toadfish (Batrachomoeus trispinosus) which lots of babies! These fishes tend to be found underneath rocks.

Here's a closer look at the numerous juvenile toadfish! How cute they are! :)

A seahorse is not a horse but a fish! Here's both the yellow and dark version of the Estuarine seahorses (Hippocampus kuda).

Here are two crabs that are rather tiny and well camouflaged. I do not know what is the one of the right but the one on the left is a Spider crab (Superfamily Majoidea).

With numerous sponges, BB is a fantastic reef to spot nudibranchs! The ones found on this trip include Spotted foot nudibranch (Tayuva lilacina), Bohol nudibranch (Discodoris boholiensis),
Denison's nudibranch (Dendrodoris denisoni), Black-margined nudibranch (Doriprismatica atromarginata), Actinocyclus nudibranch (Actinocyclus sp.), Beaded nudibranch (Hoplodoris nodulosa) and Blue dragon nudibranch (Pteraeolidia ianthina).

This Bordered sea star (Craspidaster hesperus) is very rarely sighted on our shores. How awesome to see it at on this trip! I have only seen it at BB in 2008 and also Tanah Merah in 2009.

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.On its oral side, you can see that it has pointed tube feet.

I was stunned to find this large maroon Basket star (Family Euryalidae)! My first time seeing such a large individual in this colour. They are rarely seen on our shores.

Here's a collage showing how large it is with my hand and our friends as scale. Also shown are the aboral (upper) and oral (under) sides of the basket star.

As we fast-forward time to August 2015, BB remains tranquil and charming especially during dawn. How are the marine organisms doing?

One of the first sightings after landing during the dark would be this large Snaky sea anemone (Macrodactyla doreensis) that is uncommon on our northern shores. They are named snakey anemones because of their snake-like tentacles that tend to curl. We later saw another one submerged in murky waters when we were about to depart.

Jianlin found this crab that was carrying a zoanthid. This crab could be the same or similar to the one that carries anemones.

Ria spotted this large and chubby Curvespine cuttlefish (Sepia recurvirostra) that has been sighted on our northern shores. I think it is the first time seeing this fellow.

Chay Hoon later found another smaller cuttlefish which I feel I wouldn't be able to spot on my own.

For some unknown reasons, there were many of these Slender ceratosoma nudibranchs (Ceratosoma gracillimum) that are rarely seen on the intertidal shore.

I also spotted this pair of Bornella nudibranch (Bornella sp.) that were originally stranded on the shore as the tide went out.

How is the sponge situation at BB? We were curious to find out about the state of sponges here because we observed many sponges went missing on our northern shores. Though it's a relief that there are some sponges of different types on BB, I find that there are certain types and species that are missing on this survey, in particular the branching ones.

We still see several of these large and "elderly" Thorny sea urchins (Prionocidaris sp.) on BB. The ones that we see on all other shores are usually a lot smaller with more "clean-looking". However, I feel that there were fewer from my observation this year. 

After only seeing a few of these Knobbly sea stars (Protoreaster nodosus) last year which was worrisome, we are relieved to find about 6-8 of them on this trip. Believed to be the survivors since the 2007 flood, these knobblies are what's remaining as we do not see any juveniles on any of our BB surveys. The population may not be sustainable in the long run.

Talking about sea stars, the Cake sea stars (Anthenea aspera) are always a delight to find as they come in various colours and patterns.

There are some Sea fans (Order Gorgonacea) near the edge of the reef but strangely not as abundant as beaten-shores such as Changi. I totally missed the tiny white basket star that was clinging onto the sea fan until I processed the photo at home.

What a lovely surprise to once again find the Marbled Sea Snake (Aipysurus eydouxii). Like other sea snakes, it has a flattened paddle-shaped tail used like an oar to swim with, and valved nostrils which it can close when submerged. Though this is a venomous snake, it will not bite unless disturbed.

On the overall, comparing BB over the two years, I felt that there are less sponges and corals. No Bailer volute (Melo melo), seahorses nor feather stars were sighted this year. What's also missing over the years would be the numerous large Ball flowery soft corals that used to be plentiful at the Eastern shore of BB. The distribution and abundance of zoanthids have increased too, which makes BB less reefy and "spongey".

Towards the end of our trip this year, we were treated to a spectacular and postcard-worthy sunrise over the horizon facing Pengarang, Johor.

Here's a closer look at the rising run peeking from hills of Pengarang.

On our way back, we saw some oil rigs parked near the mouth of Johor River.

Talking about Johor River, there was been recent news that it will be dammed to stop seawater intrusion since there has been concerns about low levels of water in the reservoir upstream of the river. This would likely change the hydrodynamics and salinity of the waters near the river mouth and we do not exactly know how it would impact or affect the northern shores nearby such as Chek Jawa, Pulau Sekudu and BB.

The 2030 landuse plan by the Ministry of National Development announced that Beting Bronok and Pulau Unum have been granted 'Nature Area' status. Based on our understanding, this status means the area "will be kept for as long as possible until required for development". We also do not exactly know the future of this reef with the nearby developments and land use that will go on with years to come. Meanwhile, we hope for the best and wish that BB will continue to thrive as long as it can.

More photos from the 2014 trip here:

More photos from the 2015 trip here:

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