The Strait of Malacca is the longest strait (1,120 km) in the world. It is bordered by four littoral states, Thailand, Indonesia, Malaysia and Singapore, and situated between the west coast of
Peninsular Malaysia and the east coast of Sumatra Island,  Indonesia. The Strait of Malacca receives strong influences from two predominant monsoons, the Northeast monsoon (December – February) and the Southwest monsoon (June – August). In between the two predominant monsoon seasons, there are inter-monsoon seasons. The water of the Strait of Malacca is generally calm but there are occasional thunderstorms with squalls giving rise to wind gusting up to 50 knots during the Southwest monsoon and the two inter-monsoon seasons in the Southwestern region of the Peninsular Malaysia (Kamaruzaman, 1999). Rainfall in the area is abundant, and the duration of the precipitation is generally short but often torrential and high in intensity. There are two periods of maximum rainfall in the area, which occur primarily in October – November and April – May (MMS, 2002). The Strait of Malacca acts as the ultimate sink for the fresh water runoff from the west coast of Peninsular Malaysia.

The Strait of Malacca harbours one of the largest estuarine environments, soft-bottom habitats, fringing coral reefs, seagrass beds and mangroves (Tan and Yusoff, 2002). Rich marine resources in the strait support more than 50 per cent (636,000tonnes) of the capture fisheries landing in Peninsular Malaysia (Ibrahim, 2002; FAO, 2002). The sand on the beaches of Melaka has narrow platforms composed of relatively fine-textured pyrogenic sand, which ranges from igneus (Pulau Upeh) to calcium carbonate (Pulau Besar) (Mortimer, 1993). 

The beaches of Melaka have the largest nesting population of hawksbill turtles in Peninsular Malaysia (annual records of between 400 to 600 nests) and an almost similar nesting population as Turtle Island Parks in Sabah (Table 1). The nesting beaches in Melaka, such as Tanjung Kling, Pulau Upeh and Pulau Besar, have been recognized as crucial for species protection since the 1970s (Kiew, 1975). The Department of Fisheries of Malaysia established the first turtle hatchery at Pulau Besar in 1987 (Mortimer, 1988), and in Padang Kamunting in 1990 (Mortimer, 1993).  A satellite tracking study was conducted by WWF-Malaysia from 2006-2013 for these sites to identify the migration route for the turtles and their inter-nesting habitat.

This area covers the waters and beaches from the Negeri Sembilan to the Riau Archipelago, Indonesia. The area encompasses the existing marine protected area, turtle-nesting and inter-nesting area, and turtle-feeding ground. The northern boundary of the area is 101.6ºE 2.42ºN, and the southern boundary is 104.98ºE 0.57ºN.

The Strait of Malacca is a shallow, narrow water body with an average depth of 53.38m. Malacca Strait becomes narrower and shallower at the southeastern tip. The narrowest section in the area is only about 24.9 km (Sumatra-Peninsular Malaysia). Average water depth in the southeastern part of the Strait is 39.5 m. The area receives significant freshwater run-off from the west coast of  Peninsular Malaysia. It is estimated that the Strait of Malacca receives 9.35 x 1010 m3 of freshwater every year. There is a converging and circulating current in the water off Lumut, Klang and the Port Dickson area. This complex current circulation is reducing the flushing rate in the waterway. Water quality in the Strait of Malacca is closely related to the anthropogenic activities of Peninsular Malaysia. The salinity, temperature, pH and dissolved oxygen (DO) in the area are rather consistent. There is no significant (p>0.05) difference in the hydrological parameters in the Strait of Malacca during the northeast and southwest monsoon (Hii et al., 2006).

The sea-current in the Strait of Malacca ranges from 0.088 to 0.736 m/s. Water in the Strait of Malacca generally flows north-westerly, towards Indonesian waters and the Andaman Sea during the Northeast monsoon and vice versa during the Southwest monsoon. The southern part of the Strait of Malacca receives water input from the South China Sea, Johor Strait and Rupat Strait. Although there is no large river run-off from the southern region of Peninsular Malaysia, the current in the southern part of the Strait presents a complex and instable movement. The complicated current pattern in the area is due to the narrow, shallow water. The circulating type of current in the Strait of Malacca is believed to reduce the rate of seawater flushing and extends the residential time of the seawater parcel in the waterway (Hii et al. 2006).

Although the hydrological parameters are rather stable, there are obvious water stratifications in the water of those stations situated in the northern part of the Straits of Malacca. The stratified water may be an indication of poor water mixing or a large freshwater run-off from Peninsular Malaysia. There is no obvious stratified water in the southern part of the Strait of Malacca. The water is well mixed, and there is no large river input from the southern states of Peninsular Malaysia (Hii et al. 2006).

In terms of topography, the west coast of Peninsular Malaysia is dominated by coastal plains and basins formed by alluvial deposits. Sandy beaches only found in limited areas. The eastern island of Sumatra, mainly Riau Archipelago, is generally made of granitic and old sedimentary materials that are rich sources of tin and bauxite (Chua et al., 2000).

Ecological Features

The waters off Tanjung Tuan Protected Area (figure 5) have been gazetted as a Fisheries Prohibited Area as provided for in Fisheries Regulations (Prohibited Area) (Amendment) 1994, Fisheries Act 1985. The Fisheries Prohibited Areas are Tanjung Tuan (off the promontory – in Melaka), Tanjung Tuan 1 and Tanjung Tuan 2 (off Negeri Sembilan waters), demarcated as one nautical mile from the beach with provisions for prohibition against fishing and collection of shells, molluscs and corals.

The coral communities and species composition in Tanjung Tuan are unique and differ from the coral communities of the eastern coast of Peninsular Malaysia. The coral communities are resilient and are able to survive under turbid and high stress conditions (WWF-Malaysia briefing paper, 2015 in prep). The constant growth rate of the corals makes them unique and resilient to climate change compared with other coral communities found in Malaysia. However, the corals are under threat for various reasons, such as eutrophication via untreated sewage discharged into the bay, intense collection of reef organisms, climate change (i.e., high sea surface temperatures and ocean acidification) as well as high sedimentation and turbidity (WWF-Malaysia briefing paper, 2015,in prep). This is evident from the decline in the percentage of coral cover in Tanjung Tuan and Port Dickson area from 32.9 per cent in 1976 to only 11.9 per cent in 2014 (The Star, 2015).

  Corals of Tanjung Tuan

a)        Painted and river terrapins of Sungai Linggi
Sungai Linggi is home to the painted terrapin (Batagur borneoensis) and river terrapin (Batagur affinis), both of which are listed as critically endangered in the 2014 IUCN Red List of Threatened Species. The painted terrapin population in Sungai Linggi constitutes one of the only remaining known populations in the West Coast of Peninsular Malaysia. Globally, its distribution is restricted to the Sundaland region of Peninsular Malaysia, Borneo, Sumatra and southernmost Thailand (Moll, 1985). Populations are known to be declining rapidly, with Peninsular Malaysia believed to be the last stronghold for the species, with an estimated remaining total population of a few thousand animals (CITES, 2006).
 
Painted and River Terrapins

b)        Hawksbill turtles
Melaka has the highest nesting densities of hawksbill turtles in Peninsular Malaysia, with annual records of between 400 and 600 nests.  Aside from nesting, Melaka’s hawksbills travel the whole southern part of the Strait of Malacca as their migratory corridor to the waters of Riau Archipelago (Indonesia) and neighbouring islands (Lau et al., 2009).

The seagrass bed

The Teluk Kemang, Negeri Sembilan and the Tanjung Adang-Marambong in Johor are the major seagrass beds of Malaysia. Teluk Kemang’s seagrass bed, associated with the coral reef flats, has been identified as an area of high biodiversity, with corals, gastropods, seaweeds, seagrasses, sea cucumbers and eels.  The seagrass bed in Tanjung Adang-Marambong, associated with the sub-tidal shoals, is not only the feeding ground for dugong and birds, it is also has diserve gastropods, seaweeds, sea cucumbers, fish and echinoderms. The Teluk Kanang and Tanjung adang-Marambong shoals have 10 species of seagrass, including the dugong grass Thallasia hemprichi, and are recognized as areas with a high diversity of seagrass (Japar et al., 2011). Dugongs have also been found in this seagrass bed (Japar Sidik and Muta Harah, 2002).

The sedimentation rates of Tanjung Tuan, which ranged from 0.95 to 54.3 mg cm-2 day -1 in 1979 (Liew and Hoare, 1979), increased drastically 24 years later, when they ranged from 27.31 ± 3.2 to 233.59 ± 52.04 mg cm-2 day -1 (Lee et al., 2004). This considerable increase in the amount of sediment in the coastal waters over the years may be attributed to various anthropogenic activities, such as road-building and infrastructure development as well as dredging and shipping activities.

Land-use changes around Tanjung Tuan can adversely impact the uniqueness of this area. As Tanjung Tuan fully borders Negeri Sembilan, the changes in land-use in Negeri Sembilan can impact this promontory. Negeri Sembilan also derives economic benefits from ecotourism activities in Tanjung Tuan, the main event being the raptor watch. Therefore the protection of this unique biodiversity requires joint collaboration between the authorities of Melaka and Negeri Sembilan.

Sedimentation is one of the main threats to the coral reefs in Tanjung Tuan. Corals are deemed to be stressed if the daily sedimentation rate exceeds 10mg/cm2. Based on research conducted in 2006, the daily maximum sedimentation rate in Blue Lagoon, Port Dickson (76.83mg/cm2 per day) was higher compared to other study sites, such as Langkawi (49.94mg/cm2 per day) and Pulau Redang (0.54mg/cm2 per day) (Lee and Mohamad 2011).

The coral reef as an ecosystem is likely to fail if strict measures are not taken to control sedimentation. If the sedimentation stress can be alleviated, the coral reef has a high chance to recover. While the 2013 Environmental Quality Report states that the marine water quality in Port Dickson ranges from excellent to moderate, it is still important to ensure that sedimentation is minimized.

Sungai Linggi used to be home to one of the largest nesting populations of painted terrapins in Malaysia prior to decimation of its population in the late 1990s, due to overharvesting for the pet trade and food consumption, with export to China (CITES, 2006). Major threats now include loss and degraded habitat due to clearing of riparian vegetation and riverbanks for oil palm and other activities, overharvesting of eggs for human consumption, accidental catch in fishing gear and pollution. Both species are categorised as critically endangered, due to rapidly diminishing numbers in the wild globally and imminent threats to their habitats and also wildlife trade (Horne et al., 2012). 

Marine turtles like hawksbills in Malacca are being robbed of their nesting grounds due to coastal development and land reclamation, and they are put off from landing on beaches at night by light pollution. Whilst at sea, turtles are in peril at the hands of illegal poachers and of being caught by various fishing gears such as trawlers.

Padang Kemunting beach is one of the main habitats for hawksbill turtles, with an average annual landing of 100 nests, which is 20-25 per cent of the total number of turtles in Melaka. However, the bright lighting at night on the beaches from the recreational and tourism activities is preventing female turtles from finding a suitable place to lay eggs in the dark. Similarly, hatchlings emerging from nests can become confused by bright lights that can cause them to move inland towards the light sources, rather than towards the sea. Bright lighting due to rapid development of the beachfront chalets in Kuala Linggi, Tanjung Serai beach, Meriam Patah and Tanjung Dahan also disturb the landing of turtles.