Johor losing another wetland

At the Pulai River estuary, hundreds of hectares of mangroves and a huge seagrass bed in the middle of the Johor Straits are about to make way for development.

Few picnickers would dare to plunge into the silty, smelly waters at Pantai Lido in Johor Bahru. For decades, the heavily populated city has been discharging pollutants directly into the Johor Straits, contaminating the waters with sewage, heavy metals, oil and all kinds of garbage.

But less than 50km away in the southeast corner of Johor, where the straits meet the open sea, the water condition is significantly different.

In fact, one will be amazed by the richness of the marine life that abounds in this area, and inparticular, the seagrass bed over a kilometre in length and between 80-100m wide at Tanjung Kupang. It is arguably the largest seagrass bed in Peninsular Malaysia.

The seagrass bed at Tanjung Kupang is exposed at low tide, resembling a huge, verdant carpet between Johor and Singapore. Taking advantage of the tide, wading birds flock to the area to feed and fishermen scour the seagrass bed for clams, sea cucumber and udang belacan.

The mixed sand-mud bottom is not too difficult to walk on, but it would be impossible to wade from end-to-end on this extensive 'carpet' before the tide rises again.

The formation of such an extensive seagrass bed is probably due to the precipitation of nutrients carried by the nearby Pulai River estuary. The  estuary itself drains 7,633.2ha of mangrove forest, consisting of 24 species of mangrove and  boasts the largest intact tract of riverine mangrove in Peninsular Malaysia.

Despite the muddy surroundings, the waters that flow through the seagrass meadows are remarkably transparent. Giant tropical eelgrass (Enhalus acoroides) attenuates wave and tidal energy through long, dense leaves that can reach 1-1.5m in length, and has a complex root system that accretes sediment and recycles nutrients from the water column.

There are also nine other, smaller seagrass species interspersed amongst the thick foliage that share some of these ecological functions. The environment also allows seaweeds and epiphytic algae to flourish. Together, this photosynthetic marine vegetation produces rich, oxygenated waters and nutrients that support a myriad of animals.

Endangered species 

Grouper, sea perch, snapper, threadfin and white pomfret are some of the fish in the Pulai River estuary of high commercial value, while 15 species of juvenile prawns spend the first few months of their early life here before migrating offshore.

Though the economic value of the seagrass bed at Tanjung Kupang has hardly been evaluated locally, scientists abroad have estimated that a hectare of seagrass bed contributes US$3,000 annually to fisheries alone.

The denizens of the seagrass bed at Tanjung Kupang include several endangered species listed by the World Conservation Nation. A cryptic fish, which is superbly camouflaged amidst the submerged canopy and popularly known for its male pregnancy, is no other than the seahorse. 

The mixed brackish-marine environment in the Pulai River estuary is inhabited by one seahorse species (out of 34 species found globally), scientifically known as Hippocampus kuda. The seahorse's vertical body allows it to manoeuvre steadily in the dense seagrass foliage while its prehensile tail grapples onto most substrates.

A close relative of the seahorse, the crocodile pipefish Syngnathus biaculeatus, is also a seagrass-dweller. The elongated, greenish body of the pipefish exhibits an astounding mimicry to the Giant Tropical Eelgrass, while its facial features look somewhat like a crocodile's. What is more interesting is that the pipefish is usually found in pairs, with each male carrying a few hundred eggs below its abdomen.

Perhaps the most enigmatic creature that frequents the seagrass bed is the seacow or dugong. Once hunted for food by the aborigines in the Pulai River estuary, the seacow population has declined to the extent where they are now rendered critically endangered globally. The latest human-dugong encounter in the Pulai River Estuary was dismal. In 2003 a 1.3m- long baby dugong was killed when it was entangled in a drift net at Pulau Merambong.

Protection and development

The Johor government made the right move in 2002 when it designated 9,126ha of mangrove forest along the Pulai River as a Ramsar Site. The unique estuary fulfils the criteria for Ramsar Site selection as set by the Convention of Wetlands. It contains representative, rare or unique wetland types, and endemic species of conservation importance that are under threat, as well as supports a large population of waterbirds and juvenile fish stocks.

The Ramsar Convention requires the Malaysian government to take all necessary measures to ensure the maintenance of the ecological character of Ramsar Sites. However, the original Ramsar boundaries of the Pulai River mangrove site have been realigned to accommodate the presence of the Port of Tanjung Pelepas (PTP), a coal-fired power plant and a petrochemical station on the western bank of the Pulai River.

These mega projects are putting tremendous pressures on the biodiversity in the area. The port, when the second phase of its expansion is complete, would narrow the river mouth by more than 50 percent. This could alter the tidal prism, salinity regime and water circulation within the river thus affecting the biotic communities. The migration pathways of estuarine fauna could be blocked as their habitat corridors get destroyed.

In addition, flooding may occur upstream and worsen in the rainy season. These situations are likely to be aggravated by a 122ha bunker built directly on the river mouth. The power plant, occupying 361ha, may cause the surrounding water temperature to rise through its discharge of heated water effluent. A slight increase in water temperature is known to kill off most marine life.

We may wonder why the government gave the green light for such destructive projects to take place in such an environmentally sensitive area.

The construction of the petrochemical station will mean a permanent loss to one huge area of pristine mangrove forest. In the petrochemical station's operational phase, oil, heavy metals, PCBs, radionucleoids may be discharged into the water. The effects of these contaminants cause both acute and chronic toxicity to all marine fauna and flora and remain a long time in the human food chain. 

On the eastern bank of Pulai River Estuary, an 8km strip of mangrove shoreline has been earmarked for the construction of a warehouse joining the PTP to the Second Link Causeway. Have we not learned to appreciate the roles of mangroves in saving lives and properties after the catastrophic tsunami last December? 

The seagrass bed at Tanjung Kupang will also be hard hit by the warehouse construction, as the loss of mangroves acting as buffer zones may propel sediment loading and siltation on the seagrass bed.

Worse, plans are in store to allow cargo vessels to navigate through the Johor Straits. It is feared that the seagrass bed, which occurs too near the navigation lane, will be devastated by waves generated by cargo vessels if not dredged. Pulau Merambong, which harbours coral reefs and seaweeds, is also likely to be affected by the shipping activities.

Few success stories

Had all such environmental impacts been accounted for, the projects would probably have been barred by the Department of Environment. The validity of the environmental impact assessment report on these projects is highly questionable. Somehow, political influence reigns, as the port of Tanjung Pelepas is the country's top priority development project.

It would be absurd to believe that with the advent of massive development, the ecological character of the Ramsar Site can still be preserved. Most damage done is irreversible. Restoration can be costly, in terms of time and money; besides, there are few success stories to date.

The United States, for example, had to spend $8 billion to cope with the environmental problems created by developmental activities in the Everglades, Florida. For the restoration of natural mangrove forests, experts claimed that it would cost US$9,990 per hectare per year.

In developed countries like the US, legislation requires developers to compensate for wetland loss through restoration or creation of another wetland on a hectare for hectare(s) basis. Are our developers willing to pay the price if such a quota is also introduced in Malaysia? Proper mitigation measures are clearly cheaper yet more effective than restoration. 

Wetland International director Dr Sundari Ramakrishna has cautioned that, for development to take place in the coastal areas, 500m buffer zones of mangroves should be retained to mitigate impacts of erosion and flooding. She said Malaysia, which is a party to the International Environment Agreements such as the Ramsar Convention since 1994, has a responsibility and obligation to ensure that total caution must be taken to prevent any irreversible damage to the wetlands and to the integrity of the wetlands in terms of its ecological functions.

Defiance, ignorance and lack of commitment from both developers and the relevant authorities have led to the disappearance of a huge expanse of seagrass at Tanjung Adang. That seagrass bed, the size of several football fields, was reclaimed by PTP over the past two years. Now the port is closing in on another seagrass bed lying just a couple of kilometres away at Tanjung Kupang, the last one in the Johor Straits.

By

CK CHOO (a marine biologist at the Kolej Universiti Sains whose interest is doing research on seahorses)