4. Hong Kong Soft Shores

Shallow soft-sediment habitats are under threat and degraded by intense coastal urbanisation, pollution, overfishing and direct habitat loss. These habitats are concentrated near sources of sediment supply, i.e. estuaries, which bear the grunt of the most drastic environmental change among all marine habitats.

Globally, ecosystems such as mangrove forests are considered amongst the most endangered ecosystems of the world. This challenge is particularly strong in burgeoning East Asia.

The soft-sediment habitats of Hong Kong, as part of the megalopolis of the Pearl River delta supporting >65 million inhabitants, face particularly immense pressures that threaten their functionality. As part of the Pearl River estuary, the Mai Po Marshes-inner Deep Bay ecosystem, especially, is threatened by sustained eutrophication (i.e. nutrient enrichment) and other pollution, as well as disturbances related to urbanisation, all potentially compromising its conservation value.

Key Hong Kong Soft Shore Sites

Coastal environments in Hong Kong are affected by the Pearl River estuary, particularly in the western waters of Hong Kong. Freshwater outflow from the Pearl River containing a high level of sediment and nutrient content are beneficial to the marine lives inhabited in estuarine environments, by providing a nursery ground with plenty of food (planktonic organisms). Deep Bay is one of the largest estuaries in Hong Kong receiving freshwater outflow from the Pearl and Shenzhen Rivers.

Being exposed to ocean swells driven by the easterly monsoons, the Hong Kong Eastern coastline, in contrast, is minimally influenced by the Pearl River. This condition does not favour the growth and development of mangroves, which inhabit soft bottom shores. There are limited estuarine environments in the eastern parts of Hong Kong. Where mangroves occur, for instance, at Lai Chi Wo and Kei Ling Ha, these communities develop because of the presence of small local rivers and streams.

Miscellaneous soft shore habitats could be found in Hong Kong, such as sandflats, mangrove forest, mudflats, tidal flats and seagrass beds. These habitats may be found in areas like Deep Bay and Sai Kung. The following are some recommended sites worthy of your further exploration.

To spot the sites on Google Map, refer to http://www.nature.edu.hk/field_sites

Shui Hau

Photo taken by Fen Guo

 

Being a sheltered bay located on Southern Lantau Island with a semi-protected estuarine environment, Shui Hau Wan encompasses diverse soft and hard coastal habitats, such as marshes, mangroves, intertidal sand/mud flats and rocky shores.

Shui Hau is enlisted as a “Coastal Protection Area” with the purposes of conserving and retaining the natural coastlines under the Town Planning Ordinance. However, human activities adversely disrupt the habitats, threatening the species at Shui Hau in the absence of appropriate regulations and controls. Besides, Shui Hau is not enlisted as one of the Sites of Special Scientific Interest, implying that the government still does not recognise the biodiversity at the site and their conservation and scientific values.

 

Accessibility
The site can be accessed easily with public transport.


New Lantau Bus Routes

  • No.1 Mui Wo Ferry Pier ↔ Tai O

  • No.2 Mui Wo Ferry Pier ↔ Ngong Ping

  • No.11 Tung Chung Station Bus Terminus ↔ Tai O

  • No.23 Tung Chung Tat Tung Road Bus Terminus ↔ Ngong Ping

 

Biodiversity values

  • Previous research recorded more than 180 species of organisms at Shui Hau Wan, including 6 out of the 9 local true mangrove species.

  • Most of the mangrove trees in Shui Hau are short.

  • Numerous marine snails and crabs can be discovered on the marsh floor.

  • In this research, a local species of conservation significance, the horseshoe crab (Tachypleus tridentatus), has been recorded.

 

Human intervention
Disturbances:

  • Visitors engage in recreation clam-digging on weekends and holidays.

  • Overharvesting of large clams leads to the loss of species, particularly the Asiatic hard calm (Meretrix meretrix).

  • Trampling threatens juvenile horseshoe crabs and destroys the structure of the tidal flat.

  • The litter left by visitors contaminates the habitats at Shui Hau Wan.

  • According to the Lantau Development Public Engagement Report in 2016, Shui Hau was proposed for the establishment of an animal farm and exploration campsite. Those measures, if implemented, would intervene with the natural habitats of Shui Hau.


Rehabilitation:

  • WWF-HK commenced The ECF Sustainable Shui Hau Project in 2018, with the aims of reducing human disturbance, to support continued sustainable use of coastal resources, and to protect Shui Hau’s relatively high ecological value.

Mai Po Marshes

 

Photo taken by Yan Ping Loo

Mai Po is located at Deep Bay, which is the most typical estuarine environment in Hong Kong. It is not easy for inexperienced visitors to explore Deep Bay owing to the soft muddy substratum. As the largest wetland in Hong Kong, Mai Po is a Site of Special Scientific Interest. This site was also declared as a significant international wetland under the Ramsar Convention in 1995. Mai Po has various artificial and natural habitats, such as fish ponds, Gei Wai, mangroves, inter-tidal mudflats and reedbeds.

The Mai Po Nature Reserve is a restricted area designated under the Wild Animals Protection Ordinance. The site is now managed by WWF-HK. Reservation has to be made before visiting the Reserve.

 

Accessibility
Both bus and minibus will reach the outer area of Mai Po. Several minutes’ walk will take you to the WWF education centre.


Kowloon Motor Bus (KMB) Bus Route

  • 76K Long Ping Estate ↔ Ching Ho Estate


Red Minibus (RMB) Bus Route

  • 17 Yuen Long ↔ Sheung Shui

Biodiversity values

  • A high ecological diversity is found at the site.

  • Many interesting detritivores and MPB eaters are recorded in this research, including the great blue-spotted mudskipper (Boleophthalmus pectinirostris), Japanese gizzard shad (Nematalosa japonica), and bluetail mullet (Crenimugil buchanani).

  • The major mangrove plants in Mai Po are Kandelia obovataAvicennia marinaAegiceras corniculatumBruguiera gymnorhizaExcoecaria agallocha and Acrostichum auerum. Some Heritiera littoralis and Cerbera manghas (beware of poisonous fruit) are also found.

  • This area supports a main feeding ground and wintering site along the East Asian Australasian Flyway for thousands of migratory waterbirds each winter, including the threatened species, black-faced spoonbill (Platalea minor).

 

Human intervention
Disturbances:

  • The Mai Po Nature Reserve is a restricted zone under Cap.170 Wild Animals Protection Ordinance. Strict regulations are issued to the visitors. The Mai Po Education Centre provides an interactive exhibition area, laboratories for diverse stakeholders to learn about the flora and fauna in Mai Po, as well as to conduct scientific research in Mai Po.

  • Although Mai Po is protected, its adjacent areas suffer from human disturbances. For instance, reedbeds in Nam Sang Wai were burnt in 2018. This ruins the habitats of the birds.

  • Heavy metal pollution and eutrophication exert potential ecological pressures on the ecosystem in Mai Po.

Lai Chi Wo

 

Photo taken by Michael Ma

Situated at the North-Eastern part of Hong Kong, Lai Chi Wo is within the areas of Plover Cove Country Park and Double Haven Marine Park. Here you find one of the largest mangrove habitats in Eastern Hong Kong. You can also find other soft-bottom habitats, such as mudflats and seagrass beds (the rare intertidal seagrass Zostera japonica), at Lai Chi Wo.

Lai Chi Wo is known for its unique Hakka culture, a Site of Special Scientific Interest (designated in 1979), and a part of the Hong Kong UNESCO Global Geoparks.

Accessibility
It is relatively inaccessible. Apart from a 2-hour hike from Wu Kau Tang, you may reach Lai Chi Wo by ferry at a limited schedule.


Ferry service (Saturdays, Sundays and Public Holidays only)

  • Ma Liu Shui ↔ Lai Chi Wo


Kowloon Motor Bus (KMB) Bus Routes*

  • 275R Tai Po Market Station ↔ Wu Kau Tang (Sundays and Public Holidays only)


Green Minibus Bus (GMB) Routes*

  • 20R Tai Po Market Station ↔ Wu Kau Tang

 

*Remarks: It takes around 2 hours to hike from Wu Kau Tang to Lai Chi Wo.

 

Biodiversity values

  • The largest trees of the true mangrove, Heritiera littoralis, occur at Lai Chi Wo. This mangrove tree can grow up to 15 meters in height. You can also find a characteristic giant species of the mangrove associate Derris trifoliata at Lai Chi Wo.

  • Kandelia obovata is common at Lai Chi Wo.

  • The rare local seagrass, Zostera japonica, serve as the food and habitat for crabs and shrimps, etc.

Human intervention

Disturbances:​

  • Situated in a remote location, Lai Chi Wo does not suffer from severe human disturbance. However, marine debris do wash up onto the shore of Lai Chi Wo, which may hinder the growth of flora and fauna.

  • The increase in the number of visitors may adversely affect the habitats there. For instance, visitors may step on the unique species for photo taking without supervision, causing significant damage.

Ting Kok

 

Photo taken by Yan Ping Loo

Ting Kok is located at the Eastern part of Hong Kong, at the North-Western corner of Tolo Harbour. Ting Kok is a semi-enclosed bay, which is surrounded by Pat Sing Leng, Plover Cove Reservoir, and few small headlands. Intertidal flats and a mangrove forest can be found at Ting Kok. The substrate is mainly composed of pebbles and coarse sand, which supply a relatively firm surface for walking. For this reason, one would find Ting Kok more easily accessible for examining the soft shore environment. Ting Kok was designated as a Site of Special Scientific Interest in 1985.

Accessibility
It is easily accessible with public transport.


Kowloon Motor Bus (KMB) Bus Routes

  • 75K Tai Po Market Station ↔ Tai Mei Tuk

  • 275R Tai Po Market Station ↔Wu Kau Tang (Sundays and Public Holidays only)


New Territories Green Minibus (GMB) Route

  • 20C Tai Po Market Station ↔ Tai Mei Tuk

Biodiversity values

  • A relatively rare species of true mangrove, Bruguiera gymnorhiza, occurs at Ting Kok.

  • A large population of another true mangrove species, Lumnitzera racemosa, is observed.

  • A new local mangrove crab, Haberma tingkok, which lives on mangrove trees, was newly discovered in 2018 by the Mangrove Ecology and Evolution Lab from the Swire Institute of Marine Sciences (SWIMS) and School of Biological Sciences of the University of Hong Kong.

Human intervention
Disturbances:

  • The recent construction of the artificial beach at Lung Mei takes place in adjacent areas of Ting Kok. This would potentially exert adverse disturbances to the habitats at Ting Kok.

  • Over-digging and exploitation of shellfish results in damage to the food chain.

  • Heavy algal blooms (red tide) are occasionally observed in summer at the Tolo Harbour. Sewage from residential areas flowing into Plover Cove could result in eutrophication and subsequently trigger red tide occurrence.


Rehabilitation:

  • In 2012, The Agriculture, Fisheries and Conservation Department (AFCD) set up a programme "Ting Kok Coastal Conservation Plan (Ting Kok+)" to promote public awareness on coastal ecology and conservation. The Education University of Hong Kong also collaborated with that programme to design educational kits for primary and secondary school teachers.

  • A number of green groups organize marine clean up campaigns nearby. For example, the Environmental Association started a "CCAT" scheme targeting the general public, involving them in coastal clean-up activities and ecological guidance at Ting Kok.

Tai Tam Bay

 

Tai Tam Bay, located at Southern Hong Kong Island, supports mangroves and intertidal sand flats. It is surrounded by Shek O Country Park and Tai Tam Country Park. Due to the rocky landscape and urbanised coastlines, few mangrove stands can be found on Hong Kong Island. As such, Tai Tam Bay is the only site on the Island that has mangroves. It was designated as a site of Special Scientific Interest in the 1970s.

 

Accessibility
It is easily accessible with public transport.


City Bus Route

  • No.314 Siu Sai Wan (Island Resort) ↔Stanley (Circular)


New World First Bus Route

  • No.14 Sai Wan Ho (Grand Promenade) ↔ Stanley Fort (Gate)

Biodiversity values

  • Even after the construction of the Tai Tam reservoir, some stream water still flows into Tai Tam Bay and provides an estuarine environment to mangroves (although only two species of true mangroves can be found there).

  • The grasses Zoysia sinica and Sporobolus virginicus dominate the salt marshes.

  • The salt marshes support abundant ocypodid crabs and small grapsoid crabs populations.

 

Human intervention
Disturbances:

  • Recreational sites nearby attract visitors, which may lead to increased human disturbance at the Bay.


Rehabilitation:

  • An NGO called Tai Tam Tuk Foundation organizes campaigns to advocate the protection of habitats and species at Tai Tam Bay.

Kei Leng Ha, Sai Keng

 

Sai Keng, which is along the coast of Tolo Channel, is nestled in the Sai Kung peninsula. The habitats found at this site include mudflats and mangroves. In the past, the area behind the mangroves was paddy fields. Sai Keng lies within Kei Ling Ha Mangal Site of Special Scientific Interest. Another mangrove stand, Kei Ling Ha Lo Wai, is next to that stand. The close proximity of the mangrove stand to the village makes it vulnerable to anthropogenic impact.

 

Accessibility
The site can be reached by public transport, but visitors have to go through a local village (private land) to get to the site.


Kowloon Motor Bus (KMB) Bus Routes

  • No.99 Heng On ↔ Sai Kung

  • No.299X Sha Tin Central ↔ Sai Kung

 

Biodiversity values

  • The two most common true mangrove species in the site are Avicennia marina and Kandelia obovata.

  • Some uncommon hard shore ground-dwelling faunal species are found at Sai Keng, such as a species of limpet called Cellana toreuma and a species of crab called Nanosesarma (Beanium) batavicum .

 

Human intervention
Disturbances:

  • Village development sprawl and dumping of construction waste impact the estuarine environment.

  • Local villagers and visitors dig for calms at the mudflat during low tides.

  • Recreational facilities nearby, such as sports clubs, may affect the habitats at Sai Keng.

  • There are mariculture rafts at the bay of Kei Ling Ha Hoi in the vicinity of Sai Keng.

Sheung Pak Nai

 

Photo taken by Yan Ping Loo

Sheung Pak Nai is located at North-Western New Territories. This site comprises of soft and deep muddy substratum, particularly in the foreshore areas. Local aquaculturists have long worked at aquaculture ponds and oyster farms in Pak Nai. Sheung Pak Nai is designated as part of the Pak Nai Site of Special Scientific Interest.

 

Accessibility
The site is accessible with minibus.


New Territories Green Minibus (GMB) Route

  • No.33 Yuen Long (Tai Fung Street) ↔ Ha Pak Nai

Biodiversity values

  • Uncommon seagrass species, Halophila ovalis and H. becarrii, have been recorded. Their current status is, however, unknown.

  • A record indicated that the true mangrove species Kandelia obovata was planted in the 1980s by local farmers in attempt to protect their fishponds from erosion.

Human intervention
Disturbances:

  • Spilling of fuel oil nearby by illegal smugglers happened in the late 1990s. The smugglers discharged oil from their fishing boats or merchant ships into the sea to escape prosecution by the Marine Police.

  • Leakage of polluted water from the West New Territories Landfill was recorded in 2018. Pak Nai was one of the affected areas.

  • Recreational facilities, including rental caravans and farms, are next to the site.


Rehabilitation:

  • Environmental NGOs, such as Green Power and The Nature Conservancy, have initiated educational campaigns for the protection of Pak Nai.

  • For instance, Green Power’s “The Cordgrass Removal Action” gathers public effort to halt the growth of the invasive Cordgrass (Spartina alterniflora) and to rehabilitate the habitats at Pak Nai.

  • The Nature Conservancy launched the permanent Hong Kong Oyster Reefs Exhibition Project to advocate the conservation value of oyster reefs.

 

References

Books

Morton, B. and Morton, John. (1983). The Seashore Ecology of Hong Kong. Hong Kong University Press.

Lee, S. Y. (Ed.). (1999). The Mangrove Ecosystem of Deep Bay and the Mai Po Marshes, Hong Kong: Proceedings of the International Workshop on the Mangrove Ecosystem of Deep Bay and the Mai Po Marshes, Hong Kong, 3-20 September 1993. Hong Kong University Press.

Tam, N., Wong, Y., & Hong Kong Agriculture, Fisheries Conservation Department. (2000). Hong Kong mangroves. Hong Kong: City University of Hong Kong Press.

Tam, N., Wong, Y., & Hong Kong . Agriculture, Fisheries Conservation Department. (2000). Field guide to Hong Kong mangroves. Hong Kong: City University of Hong Kong Press.

李成業., 郊野公園之友會, & 香港 . 漁農自然護理署. (2003). 漫步水上森林 (第1版. ed., 放眼大自然系列). 香港: 郊野公園之友會 : 天地圖書有限公司.

方靜威., 賴志誠., 呂德恒.& 賴志誠,. (2005). 河口生物 : 紅樹林, 泥灘及海草床 (香港自然圖鑑系列 ; 2). 香港: 野外動向.

霍年亨, 李偉展, 蔣志超, & 香港教育大學. 科學與環境學系, issuing body. (2019). 汀角生態行 : 汀角海岸環境「全方位學習」中學教材套 = Eco-tour in Ting Kok : Ting Kok coastal environment 'life-wide learning' teaching package for secondary schools (第一版. ed.).

 

Journal articles

Che, R. O. (1999). Concentration of 7 heavy metals in sediments and mangrove root samples from Mai Po, Hong Kong. Marine Pollution Bulletin, 39(1-12), 269-279.

Cannicci, S., & Ng, P. L. (2017). A new species of micro-mangrove crab of the genus Haberma Ng & Schubart, 2002 (Crustacea, Brachyura, Sesarmidae) from Hong Kong. ZooKeys (662), 67.

Lee, S. Y., & Khim, J. S. (2017). Hard science is essential to restoring soft-sediment intertidal habitats in burgeoning East Asia. Chemosphere, 168, 765-776.

Tam, N. F. Y. (2004). Conservation and uses of mangroves in Hong Kong and Mainland China. In Wetlands Ecosystems in Asia (pp. 161-182). Elsevier.

Tam, N. F., Wong, T. W., & Wong, Y. S. (2005). A case study on fuel oil contamination in a mangrove swamp in Hong Kong. Marine pollution bulletin, 51(8-12), 1092-1100.

Duke, N. C., Meynecke, J. O., Dittmann, S., Ellison, A. M., Anger, K., Berger, U., ... & Koedam, N. (2007). A world without mangroves?. Science, 317(5834), 41-42.

Morton, B. (2016). Hong Kong’s mangrove biodiversity and its conservation within the context of a southern Chinese megalopolis. A review and a proposal for Lai Chi Wo to be designated as a World Heritage Site. Regional Studies in Marine Science, 8, 382-399.

Valiela, I., Bowen, J. L., & York, J. K. (2001). Mangrove Forests: One of the World's Threatened Major Tropical Environments: At least 35% of the area of mangrove forests has been lost in the past two decades, losses that exceed those for tropical rain forests and coral reefs, two other well-known threatened environments. Bioscience, 51 (10), 807-815.

 

Websites

Agricultural, Fisheries and Conservation Department. (n.d.). General Information about Mai Po Inner Deep Bay Ramsar Site. Retrieved from https://www.afcd.gov.hk/english/conservation/con_wet/con_wet_look/con_wet_look_gen/con_wet_look_gen.html

Agricultural, Fisheries and Conservation Department. (n.d.). Mangroves and fisheries associated fauna. Retrieved from http://hkecomap.net/species_distribution.php?AnimalID=7&SiteID=&offset=&lang=eng

Agricultural, Fisheries and Conservation Department. (n.d.). Ting Kok Coastal Conservation Plan (Ting Kok +). Retrieved from https://www.afcd.gov.hk/english/conservation/con_mar/TKPlus/Intro/intro.html

Environmental Protection Department. (n.d.). Ecological impact. Retrieved from https://www.epd.gov.hk/eia/register/report/eiareport/eia_1992011/HTML/Sec%205.htm

Green Power. (n.d.). The Cordgrass Removal Action Team. Retrieved from https://www.greenpower.org.hk/html5/eng/job_community_01.shtml

Ho Koon Nature Education Cum Astronomical Centre & Quality Education Fund. (n.d.). Hong Kong Biodiversity Information System. Retrieved from http://www.nature.edu.hk/

The Nature Conservancy. (n.d.). Hong Kong Oyster Restoration. Retrieved from https://www.tnc.org.hk/en-hk/what-we-do/hong-kong-projects/oyster-restoration/

Wetland Link International. (n.d.). Tai Tam Tuk Eco Education Centre. Retrieved from https://wli.wwt.org.uk/zh-hans/2014/12/%E4%BA%9A%E6%
B4%B2%E6%88%90%E5%91%98/%E5%A4%A7%E6%BD%AD%E7%AC%83%E7%94%9F%E6%80%81%E6%95%99%E8%82%B2%E4%B8%AD%E5%BF%83/#tab-2


WWF-HK (n.d.). Code of Conduct for clam digging activities. Retrieved from https://www.wwf.org.hk/en/whatwedo/oceans/advocating_for_more_marine_protected_areas/code_of_conduct_for_clam_digging_activities/

WWF-HK (n.d.). Mai Po Nature Reserve. Retrieved from https://www.wwf.org.hk/en/whatwedo/water_wetlands/mai_po_nature_reserve/

WWF-HK (n.d.). Shui Hau Conservation in Focus. Retrieved from https://www.wwf.org.hk/news/?21840/Press-Release-Shui-Hau-Conservation-in-Focus

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