Habitat and Biodiversity on the Korean Coast of the Yellow Sea

¹⁾Jong-Geel Je, ¹⁾Si-Wan Lee, ¹⁾Sang-Ho Shin, ²⁾Dong Hynn Lim

¹⁾ Korea Ocean Research & Development Institute

²⁾ West Fisheries Institute

Abstract

The Korean coast of the Yellow Sea, which is a semi-enclosed sea between the mainland China and Korean Peninsula, has complex coastline, gentle slope and large tidal range. The coast consists of diverse habitats due to jagged coastline and many islands scattered around the shallow water. Tidal flats are especially well developed, but have been reclaimed mainly for agriculture.

So far, approximately 1,600 species were reported from marine and coastal habitats in the Korean Yellow Sea, including 70 phytoplankton, 300 benthic diatoms, 300 marine macroalgae, 50 halophytes, 500 marine invertebrates, 150 fishes, 230 water birds and 10 marine mammals. Among them 1,482 species are identified to species level. The sub phylum Vertebrata with 389 species is the most abundant taxanomic group. Also among them, 28 species including 23 shorebird species are endangered. At present, marine biodiversity of this coast is declining due to mainly habitat loss by reclamation and heavy coastal development. During past decades, the coastal habitats have been reclaimed, resulting in the loss of approximately 25% of the total tidal flats in Korea. Number of species and population sizes of fish resources are also being reduced.

Conservation of coastal environment of the Yellow Sea was first considered during the 1990s by groups of NGO members, scientists, officers, nature photographers and others who concerned about the problems of habitat loss. Their efforts have been concentrated in establishing protected area on tidal flats and a reclamation lake and building environmental education capacity. Their activities will be discussed.

Status of Korean coast of the Yellow Sea

The Korean peninsula is surrounded by the seas, of which coastline is 11,500km long including coastlines of 3,153 islands in the Korean seas. The characteristic of eastern, western and southern coasts is quite different each other. The profile of eastern coast is steep, simple and directly connected to the bottom of the sea. Sand beaches and rocky shores are well developed along the coastline. Contrary to the eastern coast, the southern and western coasts are much more complex, and many islands are scattered around the shallow seas. Due to shallow water depth, gentle slope and large tidal range, tidal flats are well developed and continental shelf is distinctive. The total area of the continental shelf including the tidal flats is 345,000㎢ which is 3.5 times the entire land area. More than 80% of these areas are located in the western coast of Korea. The tidal flats are especially well developed compared to others in the world, occupying 2.2% of entire area of the country (Ministry of Maritime Affairs, 1998). Both provinces of Kyonggido, including Inchon City and Chollanamdo occupy about 80% of total tidal flat in Korea (Fig. I).

However, many years of aggressive landfill and reclamation works have filled out the curvatures and straightened the coastal lines. Approximately 2,393km² of the tidal flats exist in the western and southern coastal areas, and many of them are recognized as internationally important wetlands. The total area of the coastal wetland continues to shrink, particularly in the western coast. If various reclamation projects are implemented as planned, more than 80% of the tidal flat will disappear or at least be seriously damaged within the first decade of next century (Je, 1999).

The tidal flat in Korea started to undergo small changes at Kangwha Island near the Han River estuary from about eight hundred years ago. At first these changes were small and localized throughout Korea. Then, since the 1970s, they accelerated and spread across the entire tidal flats. During the last three decades, this area of remarkable biological diversity has been intensively developed for industrial, agricultural and commercial uses (Je et al., 1998). Large areas of tidal flat existed near many rivers that flow into the Yellow Sea. If the Saemangum Reclamation Project takes place as it is planned (Fig. 2), the Han River estuary will be left as the only one extensive estuarine tidal flat in its natural state.

Recently, the Korean government shifted its coastal wetland policy from development to conservation and officially cancelled a land reclamation plan. A new Wetland Conservation Act has been enacted and will go into effect shortly.

Figure 1. Map showing the size of tidal flats in each province. Kyonggido including Inchon City and Chollanamdo occupy around 80% of Korean tidal flat.

Figure 2. Map showing major reclamation areas.

Marine fauna and flora

The western coast of Korea (the eastern side of the Yellow Sea) has diverse habitats due to jagged coastlines and many islands scattered around the shallow sea. Intertidal flats are the most significant ones among coastal habitats. The tidal flats have several different types such as mudflat with saltmarsh, sand flat with gravel beach, sand dune or eelgrass bed, and mixed flat. These flats support important food resources and ecological niche for diverse organisms, and provide feeding and wintering/summering grounds for migratory birds (KORDI, 1999). The coastal shallow sea that encompassing more than 1,000 islands also provides a good habitat for marine organisms and a fishing ground of high productivity.

Approximately 1,600 species were reported from marine and coastal habitats in the Korean Yellow Sea, including 70 phytoplankton, 300 benthic diatoms, 300 marine macroalgae, 50 halophytes, 500 marine invertebrates, 150 fishes, 230 water birds and 10 marine mammals. Among them 1,482 species are identified to species level (Table 1). The sub phylum Vertebrata with 389 species is the most abundant taxanomic group.

Table. 1. Species number of plant divisions and animal phyla recorded from the Korean Yellow Sea

Plants	Division Bacillariophyta	312
	Division Cyanophyta	18
	Division Cryptophyta	1
	Division Euglenophyta	1
	Division Pyrrhophyta	37
	Division Magnoliophyta	5
	Division Chlorophyta	34
	Division Phaeophyta	65
	Division Rhodophyta	172
Subtotal		645
Animals	Phylum Porifera	7
	Phylum Cnidaria	34
	Phylum Plathyhelminthes	1
	Phylum Bryozoa	3
	Phylum Brachiopoda	2
	Phylum Sipunculida	1
	Phylum Mollusca	135
	Phylum Annelida	87
	Phylum Arthropoda	148
	Phylum Echinodermata	24
	Phylum Chaetognatha	5
	Phylum Chordata	390
	Subphylum Vertebrata	(389)
Subtotal		837
	Total	1482

In recent year, there has been a decreasing tendency in number of species and population size notably in commercial fishes. This is mostly due to the reclamation of the tidal flats, water pollution and over-exploitation. Tidal flats on the western coast are easy to be reclaimed, thereby causing short-sighted and careless development, which bring habitat degradation and loss of breeding and nursing sites for fishes. The areas of eelgrass beds, which are most important wetland for breeding and nursing of marine organisms in the Yellow Sea, are also being reduced.

The fishing activities that take place on tidal flats can be categorized into fishing of fin fishes and shellfish, and aquaculture. Major fishing activities on the tidal flats focuses on shellfish, especially on mollusks. Tidal flats also produce about 50,000~90,000 tons of clams annually. Other fishery animals include mud octopus and polychaetes. Over 1,000 tons of mud octopus and 500 tons of polychaetes are caught annually.

Many marine organisms are cultured, the most representative ones being laver and various mollusks. Oysters are mainly raised and harvested in the western coast of Korea. Hard clams are mostly produced in the estuarine coast of Chollabukdo Province. The hard clam prefers estuarine tidal flats and is mostly produced in the Saemankum Reclamation Area, which is located in the Mankyung River and the Dongjin River estuaries. It is anticipated that the hard clams will disappear with it, reclamation of the Saemankum area is being completed.

Endangered and endemic species

Biological diversity in Korea is declining mainly due to habitat loss by coastal development. Korea Association for the Conservation of Nature (KACN) listed 179 species as extinct, endangered and protected species (Kwon et al., 1998). Among them, 29 species are endangered or reserved wild marine animal species, which consist of 2 mollusks, 23 waterfowls, and 4 mammals including spotted seal Phoca largha (Table 2). Many invertebrates might be endangered, but the exact status is unknown. A total of 16 species, two mammals and 14 birds, are protected as natural monument species. The bird group includes cranes, spoonbills, swans and oystercatcher (Table 3) (Yoon et al., 1998).

The Yellow Sea has specific oceanographic conditions as semi-enclosed sea and has notable cold water mass and ecological barrier with big gradients of salinity and water temperature. The barrier is believed to make the Yellow Sea isolating from the Pacific Ocean. Therefore it is anticipated that endemism of marine organisms, especially benthic invertebrates might be high. However, the diversity of endemic species is not well studied, nor is the rate of loss in the species diversity. There is no comprehensive data on introduced species in the Korean Yellow Sea. A few introduced barnacle species is found in harbor area which transported by ballaster water of trade ships. Little study has been made for genetic diversity as well.

Table. 2. List of endangered species and preserved species of the west coast of Korea

by Natural Environment Conservation Law

Species Name	Common Name	Number of Natural monument	Remarks
Mammalia	Mammalia
Lutra lutra	Otter	330	Endangered species
Callorhinus ursinus	Northern Fur Seal		Preserved species
Phoca largha	Spotted Seal	331	"
Aves	Aves
Egretta europhotes	Chinese Egret	361	Endangered species
Ciconia boyciana	White Stork	199	"
Platalea leucorodia	Spoonbill	205	"
Platalea minor	Black-faced Spoonbill	205	"
Cygnus olor	Mute Swan	201	"
Haliaeetus albicilla	White-tailed Eagle	243	"
Falco peregrinus	Peregrine Falcon	323	"
Grus japonensis	Manchurian Crane	202	"
Eurynorhynchus pygmeus	Spoon-billed Sandpiper		"
Tringa guttifer	Spotted Nordmann's Greenshank		"
Phalacrocorax pelagicus	Pelagic Cormorant		Preserved species
Anser fabalis	Bean Goose		"
Anser cygnoides	Swan Goose	325	"
Cygnus columbianus	Whistling Swan	201	"
Cygnus cygnus	Whooper Swan	201	"
Anas formosa	Baikal Teal		"
Mergus squamatus	Scaly-sided Merganser		"
Grus monacha	Hooded Crane	228	"
Grus vipio	White-naped Crane	203	"
Haematopus ostralegus	Oystercatcher	326	"
Charadrius placidus	Long-billed Ringed Plover		"
Numenius madagascariensis	Australian Curlew		"
Larus saundersi	Saunder's Gull		"
Mollusca	Mollusks
Ellobium chinense			Preserved species
Clithon retropietus			"

Table. 3. List of natural monument animals inhabited in the west coast of Korea

Name of Species	Common Name	Number of Natural monument	Designated Date
Ciconia boyciana	White Stork	199	1968. 5. 30
Cygnus columbianus	Whistling Swan	201	1968. 5. 30
Cygnus cygnus	Whooper Swan	"	"
Cygnus olor	Mute Swan	"	"
Grus japonensis	Manchurian Crane	202	"
Grus vipio	White-naped Crane	203	"
Platalea minor	Black-faced Spoonbill	205	"
Platalea leucorodia	Spoonbill	"	"
Grus monacha	Hooded Crane	228	1970. 10. 30
Falco peregrinus	Peregrine Falcon	323	"
Anser cygnoides	Swan Goose	325	"
Haematopus ostralegus	Oystercatcher	326	"
Lutra lutra	Otter	330	"
Phoca largha	Spotted Seal	331	"
Egretta europhotes	Chinese Egret	361	1988. 8. 23

Critical habitats and protected areas

Although, the significance of estuaries was recognized, and conservation efforts have been made, the efforts have been hardly effective. Attempts were made to designate the tidal flat in the southern part of Kanghwa Island adjacent to the Han River estuary as a protected area (Ministry of Environment, 1994).

In the western coast, there are three national parks – Taean Haean (coastal) National Park, Byensan Bando (peninsula) National Park and Tadohae Haesang (marine) National Park and six natural monument sites for one or two single species (National Park Authority, 1997). An effort to protect the national parks is mainly focused on landscape and seascape than on marine ecosystem. Some government agencies and NGOs are concerned about the problems of habitat loss, and consider protection of the coastal environment of the Yellow Sea. Their efforts have been concentrated in estuaries, tidal flats, artificial lakes and other coastal wetlands. These areas have long been recognized as special places with a unique range of life and breeding and feeding areas for water birds or migratory birds of international significance. Although there are regulations and laws such as Wetland Conservation Act, Natural Environment Preservation Act, Wildlife Preservation and Game Act etc. to conserve coastal environment, no marine protected area is designated in Korea at the present (Republic of Korea, 1999a). According to water bird census investigated in the coastal area every year, more than 10 sites are included in Ramsar site craters (Figs. 4, 5).

Figure 4. Map showing marine and coastal national parks located in the west coast of Korea.

Figure 5. Map showing natural monument protection sites (solid circles) and sites in criteria of Ramsar convention distinct (solid triangles) in the west coast of Korea.

Some estuaries in west coast of Korea are very important for fishes and useful invertebrates as rearing and migratory habitats. Intertidal wetlands are internationally known as visiting or wintering sites for migratory birds for it is part of west Pacific flyway from Siberia to Australia and East Asian countries. Many estuarine habitats have been lost owing to diking for agricultural, industrial, and urbanization activities since 1970s. Some lakes in the reclaimed land became good feeding and resting-place for migratory birds, especially duck’s families.

A total of 116 species of waterbirds and 17 of Falconiformes were recorded during 1994-1997. The total peak number was 550,000 for wintering waterbirds and 140,000 for migrating waders from 11 bird census sites in west coast of Korea. All of the sites can be considered as internationally important wetlands for water birds according to the Ramsar Convention criteria (Table 4). However, most of sites have been degraded mainly by reclamation, water pollution and unsustainable tourism. The population of ducks have been gradually increasing in the lakes on reclaimed areas. The population of waders has been decreasing sharply. The major bird habitats in the west coast should be designated as national protected areas or Ramsar sites for efficient conservation (Republic of Korea, 1999b).

Conservation of biodiversity

The national biological diversity affairs are very complicated. However, the Ministry of Maritime Affairs and Fisheries is responsible for conservation of coastal and marine biodiversity.

Main threat to the coastal habitats is land reclamation especially at estuaries and shallow bays. During past decades, many sites have been reclaimed, resulting in the loss of approximately 25% of the total tidal flats in Korea. The reclamation the waste materials and pollutants from industrial complexes and cities located in the coastal region and visitors to coast for tourism and recreation also impact the habitats (Ministry of Maritime Affairs and Fisheries, 1998).

Under the Wetland Conservation Act, comprehensive surveys have been conducted in every five years to obtain necessary data on the natural marine environment along the coast for effective conservation of it. Surveys are also conducted in the areas where there have been apparent changes in the environment. The master plan for natural environment conservation has been worked out, based on the results of the surveys to ensure a healthy living environment for the entire population (Republic of Korea, 1999a). Several biological surveys have been carried out in Korean Yellow Sea and its coast as a part of following national projects:

l A survey for Oceanographic Atlas of Korean Waters – Yellow Sea (1982-1986) by

KORDI

l 1st National Survey on the Natural Ecosystem (1986-1990) by MOE (the Ministry of

Environment)

l 2nd National Survey on the Natural Ecosystem (1997-2001) by MOE

l Inventory Survey on Coastal Wetlands (1999-2003) by MOMAF (the Ministry of

Maritime Affairs and Fisheries)

The survey on coastal wetlands covers a wide range of factors, including the current utilization, pollution and fishery resources and any changes in use as well as distribution of flora and fauna in the coastal wetlands and reclaimed areas. In addition, the conditions of the habitats for animals and plants in coastal areas are inspected, water quality is determined, and planktonic community including red tides is observed in several different locations. MOMAF is responsible for the protection of marine life including coastal wetland’s.

Conservation of marine environment in Korea was first considered during the 1980s by concerned groups of marine biologist, ornithologist, local naturalist, NGO member, officer and others concerned about the problems of habitat loss due to land reclamation and water pollution. Their efforts have been concentrated in establishing protected area in tidal wetlands, which have feeding and resting places for migratory birds and benthic communities, and building marine environmental education capacity. Under the Natural Environment Conservation Law, the Ministry of Environment conducted a survey to designate Natural Environmental Preservation Area, a kind of protected area at the southern tidal flat of Kanghwa Island in the west coast of Korea in 1991. Some NGOs have introduced the concept of ecotourism and benefits of protected area to conserve tidal flats.

The efforts on building environmental education capacity have been aimed at public to expand awareness and appreciation of marine biodiversity and ecosystem. The number of education activities conducted by NGOs is rapidly increasing especially for tidal wetlands. In order to construct education programs to encourage students learning through discovery and personal experience on coastal and marine environment. Several workshops and training courses for teachers on marine environmental education have been held in last three years. A training course on marine conservation for local environmental educators conducted by KORDI in July 1999.

Table. 4. Sites of coastal and estuarine wetlands in criteria using waterfowl species of Ramsar by estimation in west coast of Korea (MOE), 1997, 1998, 1999.

	Sites		Major Waterfowl Species		Estimated Population		Population in World		1% level in Ramsar criteria		Remarks
Han River Estuary		White-naped Crane		385		*3,000		30		Migrated over 20,000 populations in ’96. 12 – ’97. 3.
Kangwha Island		Mongolian Plover Black-bellied Plover Dunlin Australian Curlew Black-faced Spoonbill		900 580 1,830 445 41		**27,000 ***25,000 **130,000 *21,000 *650		270 250 1,300 210 7
Youngjong Island		Mongolian Plover Snowy Plover Dunlin		870 1,201 6,707		**27,000 **25,000 **130,000		270 250 1,300
Shiwha Lake		Green-winged Teal		15,000		**1,500,000		15,000		Migrated over 20,000 populations in ’99. 2.
Asan Bay		Dunlin Australian Curlew Greenshank Terek Sandpiper		2,821 1,540 488 944		**130,000 *21,000 ***40,000 ***36,000		1,300 210 400 360		Migrated over 20,000 populations in ’96. 11 - 12 and ’97. 1 - 4.
Namyang Bay		Dunlin Great Knot Chinese Egret		8,000 5,100 47		**130,000 *330,000 *2,500		1,300 3,300 25
Daeho Lake		Baikal Teal		25,000		*105,000		1,050
Cheonsu Bay		Dunlin Biack-tailed Godwit Baikal Teal		2,097 3,935 110,003		**130,000 **162,000 *105,000		1,300 1,620 1,050		Migrated over 20,000 populations in ’96. 10 – ’97. 3.
Kum River Estuary		Dunlin Mongolian Plover Oystercatcher		7,128 450 1,169		**130,000 **27,000 *3,000		1,300 270 30		Migrated over 20,000 populations in ’96. 11 – ’97. 3.
Mankyung River Estuary		Saunder's Gull Great Knot White-naped Crane		410 17,767 130		*10,000 *330,000 *3,000		100 3,300 30		Migrated over 20,000 populations in ’96. 10 - 11 and ’97. 1 - 4.
Tongjin River Estuary		Dunlin Australian Curlew Snowy Plover		8,784 726 586		**130,000 *21,000 **25,000		1,300 210 250		Migrated over 20,000 populations in ’96. 10 - 11 and ’97. 1 - 2.
Youngsan River Estuary		(Eurasian) Wigeon		11,283		**1,000,000		10,000		Migrated over 20,000 populations in ’99. 2

*: Population in the world, **: Maximum population of subspecies, ***: Population on fly-way of migratory waterbirds (Rose, P.M. and D.A. Scott, 1994. Waterfowl Population Estimates. IWRB, 29.)

References: Ministry of Environment, 1997, 1998, 1999 ("Census datas of migratory waterbirds")
Suggestion

For effective conservation of coastal habitats of the Yellow Sea, it is necessary :

l to require more concerned research effort by both the scientific and policy communities,

l to establish new marine protected areas especially on coastal wetlands,

l to promote the sustainable development and lifestyle through environmental education,

l to develop collaborate works between countries for sharing information and experiences,

l to monitor the cumulative impacts and the environmental changes by human activities.

References

KORDI, 1999. Tidal flats studies for conservation and sustainable use. KORDI Report, BSPE 99748-00-1245-3.

Je, J.-G., J.-H. Lee and C.-H. Koh., 1998.Tidal Flat Studies : Present and Future. Ocean Research, 20(2) Special Issue : 57-235. (in Korean)

Je, J.-G., 1999. Coastal Wetland of Korea : Current Status and Protection. Nature conservation, 105 : 10-15. (in Korean)

Kwon Y.J. et al., 1998. Endangered and reserved wild species in Korea. 301pp. Kyohak Publishing Co., Seoul. (in Korean)

Ministry of Environment, 1994. Environment Protection in Korea. 292pp.

Ministry of Maritime Affairs and Fisheries, 1998. Tidal Flats of Korea. 28pp. (in Korean)

National Park Authority, 1997. National Parks of Korea. 127pp.

Republic of Korea, 1998. National Biodiversity Strategy. 85pp.

Republic of Korea, 1999a. Wetland Conservation Act.

Republic of Korea, 1999b. National Report : Yellow Sea Large Marine Ecosystem PDF-B. 169pp.

Yoon, M.B., M.-H. Suh and Y.-M. Lee, 1998. Natural monuments of Korea in color. 693pp. Kyohak Publishing Co., Seoul. (in Korean)