Mangroves growing on Pulau Hantu seawall still doing well

Today, I focused almost entirely on the mangroves growing on the artificial seawalls of Pulau Hantu. Such a joy to do this with another mangrove enthusiast - thanks Kwan Siong! Amazing to see the mangroves, reefs and all kinds of marine life just opposite the huge petrochemical plants on Pulau Bukom.

We visited the large Nyireh laut growing on the seawall, and may have found another small treelet in the Southern lagoon. But sadly, someone had chopped all the saplings that settled on the Southern lagoon. My brief look suggest the corals are mostly alright. The rest of the team make all the special finds, I will update later.

Terumbu Hantu in the face of Sudong reclamation

Despite being next to petrochemical plants on Pulau Bukom and surrounded by heavy vessel parking, this little gem with rich reefs is one of our favourite sites.

Today we survey within sight of the ongoing massive reclamation on Pulau Sudong. We are relieved to see the corals are still doing well. The rest of the team make all the special finds, I will update later.

Checking up on the whole of Pulau Hantu

A rare survey of the whole of Pulau Hantu as a large team heads out on a lovely evening low tide. Most covered the usual survey area of Hantu West, while a few checked out Hantu East which we seldom visit. 

I saw a large patch of Branching montipora corals! Through the massive annual Sargassum bloom, I got glimpses of common corals, saw a patch of Sickle seagrass for the first time, and the usual reef life common on our Southern shores.

Mangroves of Pulau Hantu with a possible special find!

Today, I focused almost entirely on the mangroves growing on the artificial seawalls of Pulau Hantu. Such a joy to do this with another mangrove enthusiast - thanks Muhd Nasry!

In the process, we think we might have come across a rare Nyireh laut! The rest of the team saw a Burrowing giant clam, colourful fish and marine life. Corals seemed mostly okay.

Terumbu Hantu plus Cigar Reef!

Despite being next to petrochemical plants on Pulau Bukom and surrounded by heavy vessel parking, this little gem is one of our favourite sites. We skipped Terumbu Hantu last year due to too many shores to check during mass coral bleaching plus Pasir Panjang oil spill.

Today, we made up for it with an all-arms assault. Part of the team set foot for the first time, on the nearby tiny submerged reef Cigar Reef, while the rest checked out Terumbu Hantu. Drones were flown. Relieved that corals are more or less okay, and the rest of team find cushion stars, slugs and more.

Majority of Singapore’s corals have recovered from 2024 Mass Coral Bleaching

Peak bleaching was in July 2024, with about 44 per cent of coral colonies surveyed reported to have been bleached, according to Associate Professor Huang Danwei, deputy head of Lee Kong Chian Natural History Museum. Extensive bleaching was observed at Pulau Hantu, Pulau Satumu, Kusu Island and Sisters’ Islands, according to Coral scientist Jani Tanzil, the facility director at St John’s Island National Marine Laboratory (SJINML).

Mass Coral Bleaching at Kusu Island, Jun 2024

“Most bleached corals that survived the marine heatwave seem to also have recovered by November 2024, with its rate of recovery similar to previous bleaching events – at least for the corals we’ve been monitoring, which are mostly at Kusu Island,” added Dr Tanzil.

On whether the series of oil spills and leaks since June 2024 have affected the recovery of coral reefs around Singapore from the bleaching incident, Dr Tanzil said that the corals have likely “escaped the immediate brunt of it”. However, long-term impacts are still inconclusive.

“(The oil spills) largely occurred not during low tides when corals would be exposed in the splash zone and to the floating oil layer. Speedy clean-up efforts have also mitigated impacts,” she said.

Pulau Hantu still alive!

Although Pulau Hantu lies just across the petrochemical plants on Pulau Bukom, there are living reefs and even mangroves here. A full team surveys at the first predawn tide of the cycle.

It was a relief to see that the reefs seem to have pulled through the Fourth Global mass coral bleaching event last year. As well as oil spills large and small. We last surveyed in Jun 2024 just after the 400tonne Pasir Panjang oil spill on 14 Jun 2024. We surveyed again in Oct 2024 12 hours after an oil spill at Pulau Bukom.

"Condos for Fish" at Pulau Hantu

To encourage the return of fish life, artificial structures made of concrete blocks, called fish houses, were deployed at the base of sea walls at five different sites at Pulau Hantu.

“This study provides more technical information on how fish houses deployed near sea walls can be designed to support higher fish diversity, which can be incorporated into future coastal defence construction,” said Dr Daisuke Taira.

Said NUS Associate Professor Peter Todd, who conceived the study on the fish houses: “As coastlines around the world are increasingly modified by urbanisation and the need to defend against sea level rise, it is vital that we find ways to mitigate some of the worst effects.”

Pulau Hantu after Bukom spill and mass coral bleaching

There was an oil spill at Bukom about 12 hours before we arrived for our survey.

We didn't smell any oil at Hantu, although the water seemed particularly murkier than usual - effect of dispersants? Fortunately, we didn't see any mass coral bleaching and most of the corals seemed to have survived. Today was also the maiden 'flight' of our brand new underwater drone!

Oil spill from Bukom refinery, 20 Oct 2024

Oil slick and sheen is seen in surrounding waters due to leakage from a land-based pipeline between Bukom Island and Bukom Kecil which happened early morning 20 Oct 2024. 

Shell stopped the leak at source, placed containment booms off the site of the leak and deployed craft equipped with dispersants to clean up the oil sighted in the vicinity of the leak.

MPA deployed 7 MPA craft to spray dispersants. As at 6pm 20 Oct 2024, no new oil sightings were reported. From media reports as below.

Mass coral bleaching on Pulau Hantu, but no oil spill impact

Although Pulau Hantu lies just across the petrochemical plants on Pulau Bukom, there are living reefs and even mangroves here. The full team visit to check up for oil spill impact and mass coral bleaching.

Good news: no sign of oil spill impact on Pulau Hantu! But mass coral bleaching is ongoing here. We estimate about 20% of hard corals were full on bleaching and another 20% of hard corals were stressed (pale, odd colours). About 10% of soft corals were full on bleaching and another 20% slightly stressed (pale). Kelvin also flew the drone for a special overview of this rich shore.

Shell sells Pulau Bukom petrochemical plants

It was reported that Shell is selling its petrochemical plants on Pulau Bukom which lies just across from the living reefs on Pulau Hantu.

Shell has agreed to sell its energy and chemicals park on Singapore’s Pulau Bukom and Jurong Island to CAPGC, a joint venture comprising Indonesia’s Chandra Asri Capital and global commodities trader Glencore. The transaction, subject to regulatory approval, is expected to be completed by the end of 2024.

Terumbu Hantu still thrives

Despite being next to petrochemical plants on Pulau Bukom and surrounded by heavy vessel parking, this little gem is one of our favourite sites.

Today, we saw lots of healthy corals and other amazing marine life. Kelvin flew the drone and got stunning views of the reef and surrounding area.

Sunny at Pulau Hantu

Although Pulau Hantu lies just across the petrochemical plants on Pulau Bukom, there are living reefs and even mangroves here. 

The last 3 surveys here, we were hit by fierce storms and rain. Today, we saw a Burrowing giant clam, lots of healthy corals and other interesting marine life on a sunny day!

Sumatras storm over Pulau Hantu

Regular shore explorers know and respect stormy weather. The pre-dawn Sumatras are the scariest. With towering dark clouds building up high winds and megavolts of lighting - in the face of one, we have long learnt to flee for cover.

Although Pulau Hantu lies just across the petrochemical plants on Pulau Bukom, there are living reefs and even mangroves here. Despite being hit by a storm in the middle of our survey, I saw healthy corals, mangroves although the seagrass situation is still sad.

Terumbu Hantu still lovely

On one of the last morning low spring tides of the year, we land at first light on a tiny submerged reef next to Pulau Hantu.

This little gem is one of our favourite sites, with lots of corals and other amazing marine life. Kelvin flew the drone and saw sea turtle, large fishes and more.

Hantu Diversion

Due to fierce weather, we divert to Pulau Hantu from our original plan to survey Pulau Jong. Thus today, explored parts of Pulau Hantu that we seldom survey.

The team found lots of soft corals, feather stars and sadly, some large dead Giant clams. Kelvin flew the drone flew when the rain stopped. I checked out the mangroves that have settled naturally on the seawalls and they are doing fine.

Pulau Hantu in the rain

Although it lies just across the petrochemical plants on Pulau Bukom, there are living reefs, seagrasses and even mangroves on Pulau Hantu.

It was good to see that these ecosystems were doing well, similar to our last survey in Apr 2021. Despite the rain, the team managed to do a quick health check and also saw interesting marine life.

Coral overload at Pulau Hantu

Although it lies just across the petrochemical plants on Pulau Bukom, there are living reefs, seagrasses and even mangroves on Pulau Hantu. 

On our last survey in Jul 2020, mass coral bleaching was seen here as well as many other shores. It was thus a relief today, to see no signs of mass bleaching in the hard corals and leathery soft corals. The rest of the team saw a Burrowing giant clam.

Terumbu Hantu not much bleaching

Dr Jani Tanzil alerted us that mass coral bleaching may have started on our shores since the second week of June. So we are on the look out for this as we check up on Terumbu Hantu. This little submerged reef just off Pulau Hantu has some lovely corals including this nice patch of Acropora corals.

Today, we didn't see many bleaching corals. I estimate about 5% of the hard corals that I saw were showing stress (paler than usual or with bleaching portions) or with recently dead patches.Most of the leathery soft corals were alright. The situation wasn't as bad as what I saw during mass coral bleaching in 2016.