CHAPTER 9 - AQUATIC AREAS AND WETLANDS
(9-A) -KEY HABITAT AQUATIC AREAS
[A1] Coral Reefs, [A2] Mangrove Swamps, [A3] Aquatic Ecosystems Generally,
[A4] Sea Grass, [A5] Lakes and Rivers, [A6] Continental Shelves
(9-B) - WETLANDS - [B1] Coastal Wetlands, [B2] Wetlands in General
(9-C) - LAND USED BY AQUACULTURE - [C1] Global Data, [C2] Asia, [C3] Latin America
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(9-A) - KEY HABITAT AQUATIC AREAS
[1] Coral Reefs, [2] Mangrove Swamps, [3]
Aquatic Ecosystems Generally, [4] Sea Grass, [5]
Lakes and Rivers, [6] Continental Shelves
[1] Coral Reefs
Worldwide, an estimated 255,000 km2 of shallow coral reefs exist, with more than 90% in the Indo-Pacific region (fi97S3). (la)
The world's (coral) reefs occupy 294,533 km2 corresponding to 0.1% of the total surface area of the world's oceans (fi01U4). (la) Comments:
Oceans occupy 361.0 km2 of the Earth's surface ((se92Q1), p. 76).
Roughly 414,000 km2 of coral reefs are scattered throughout the world's tropical and sub-tropical seas (fi96H1). (la)
Global and Regional Coral Reef Areas in 1997 ((fi00W3), p. 75) (la)
Areas are in units of 1000 km2.
Region~ ~ ~ ~ ~ |Area
World ~ ~ ~ ~ ~ |255 (100.0%)
Indo-Pacific~ ~ |233 ( 91.4%)
Western Pacific*|105 ( 41.2%)
Eastern Pacific | ~3 ( ~1.2%)
Red Sea ~ ~ ~ ~ | 17 ( ~6.7%)
Arabian Gulf~ ~ | ~3 ( ~1.2%)
Indian Ocean~ ~ | 36 ( 14.1%)
Southeast Asia~ | 68 ( 26.7%)
Atlantic~ ~ ~ ~ | 22 ( ~8,6%)
Wider Caribbean | 21 ( ~8.2%)
West Africa ~ ~ | ~1 ( ~0.4%)
(* incl.Hawaii)
If trends continue, within 4 decades only 155,000 km2 of the world's 600,000 km2 of coral reefs will be left intact and functioning (Reference citation apparently lost.) (la)
600,000 km2 of coral reefs are scattered throughout the world's tropical and sub-tropical seas (fi97H3). (la) Comments: Note the large disparity in the various estimates of the global area of coral reefs -600,000 vs. 414,000 vs. 255,000 vs. 294,533 km2
Coral reefs have been on earth for 500 million years (Ref. 13 of (fi93W2)). Most coral reefs are 5,000-10,000 years old (fi96H1). Coral reefs occupy 0.17% of the Earth's surface (probably meaning the world's oceans - 361 million km2 ), but are home to 25% of all marine fish species (Ref. 6 of (fi93W2)). Comments: 0.17% of 361 = about 600,000 km2
109 countries have shores lined with coral reefs. The total length of these coral reefs exceeds 100,000 km (fi93W2).
According to a detailed survey from the World Conservation Monitoring Center of the UN Environment Program coral reefs are both smaller and dying faster than previously thought. A large fraction of the world's reefs are threatened by human activity: Thailand and the Philippines (97%), Indonesia (82%), Malaysia (91%), Papua New Guinea (46%), and Australia (32%) (fi01U4). (la)
On 11/3/99, scientists at the US Coral Reef Task Force meeting approved a resolution calling on the US government to ban fishing from 20% of the 10,540 sq. miles (27,300 km2) of US coral reefs by 2020 (fi99B1). (la)
Australia has the second largest area of coral reefs - 50,722 km2
(fi01U4).
The Great Barrier Reefs off Australia are among the best off in the world due to the protective status of a 350,000-km2 park (fi93W2). Great Barrier Reef Marine Park (established in 1975) covers nearly 238,000 km2 (fi96H1). (la) (See Chapter (7-B) - Parklands.)
A 265-page report, "The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States," http://ens-news.com/ens/sep2002/2002-09-30-06.asp identifies the pressures that pose increasing risks to the estimated 7,607 square miles (19,700 km2) of US coral reefs.
Indonesia has the largest area of coral reefs -- 52,835 km2
(fi01U4) (la).
The Philippines have the third-largest area of coral reefs -25,899 km2 (fi01U4).
[2] Mangrove Swamps
Mangrove Swamps -- Global
Mangrove swamps line 8% of the world's coastlines (Burke et al [PAGE] 2000) and about 25% of tropical coastlines, covering a surface area of 181,000 km2 (fi97S2). (la)
Coastal mangroves now cover 200,000 km2 (global data) (fi97S1). (la)
Mangrove Areas in Selected Countries ((fi00W3), p. 74) (la)
Data of Burke et al [PAGE] 2000, Areas are in km2
Country ~ ~ ~ ~ |Current
~ ~ ~ ~ ~ ~ ~ ~ |Extent|Loss| Period of Loss
Angola~ ~ ~ ~ ~ | 1100 | 50%| Original-1980s
Coted'Ivoire~ ~ | ~640 | 60 | Original-1980s
Gabon ~ ~ ~ ~ ~ | 1150 | 50 | Original-1980s
Guinea-Bissau ~ | 3150 | 70 | Original-1980s
Kenya ~ ~ ~ ~ ~ | ~610 | ~4 | 1971-88
Tanzania~ ~ ~ ~ | 2120 | 60 | Original-1980s
Costa Rica~ ~ ~ | ~413 | -6 | 1983-90
El Salvador ~ ~ | ~415 | ~8 | 1983-90
Guatemala ~ ~ ~ | ~161 | 31 | 1960s-90s
Jamaica ~ ~ ~ ~ | ~106 | 30 | Original-1990s
Mexico~ ~ ~ ~ ~ | 5315 | 65 | 1970s-90s
Panama~ ~ ~ ~ ~ | 1581 | 67 | 1983-90
Peru~ ~ ~ ~ ~ ~ | ~ 51 | 25 | 1982-92
Brunei~ ~ ~ ~ ~ | ~200 | 20 | Original-1986
Indonesia ~ ~ ~ |24237 | 55 | Original-1980s
Malaysia~ ~ ~ ~ | 2327 | 74 | Original-1992-93
Myanmar ~ ~ ~ ~ | 4219 | 75 | Original-1992-93
Pakistan~ ~ ~ ~ | 1540 | 78 | Original-1980s
Philippines ~ ~ | 1490 | 67 | 1918-80s
Thailand~ ~ ~ ~ | 1946 | 84 | Original-1993
Vietnam ~ ~ ~ ~ | 2625 | 37 | Original-1993
Papua New Guinea| 4627 | ~8 | Original-1992-93
Mangrove forest loss in selected countries since pre-agricultural times (fi93W3) (la)
(Col. 2 gives losses in km2 ) Col. 3 gives losses in % of the original inventory.)
Indonesia ~ ~|21220 |(45% of ~47,116)
Nigeria ~ ~ ~|12320 |(50% of ~24,640)
Malaysia~ ~ ~| 7384 |(32% of ~23,075)
Cameroon~ ~ ~| 4908 |(40% of ~12,270)
Sierra Leone~| 3434 |(50% of ~ 6,868)
Guinea-Bissau| 3183 |(70% of ~ 4,547)
Bangladesh~ ~| 2940 |(73% of ~ 4,027)
Mozambique~ ~| 2787 |(60% of ~ 4,645)
Tanzania~ ~ ~| 2142 |(60% of ~ 3,570)
Philippines ~| ~785 |(80% of ~ ~ 981)
Total ~ ~ ~ ~|61103 |(46% of*131,739)
* (of the countries on the list)
Source: WRI, UNEP 1990, Australian Institute of Marine Science (1992).
Losses of Mangrove Forests in Selected Countries Since Pre-agricultural Times (df93W1) (km2) (la)
Indonesia ~ |21220 (45%)| Guinea-Bissau|3183 (70%)
Nigeria ~ ~ |12320 (50%)| Bangladesh~ ~|2940 (73%)
Malaysia~ ~ | 7384 (32%)| Mozambique~ ~|2787 (60%)
Cameroon~ ~ | 4908 (40%)| Tanzania~ ~ ~|2142 (60%)
Sierra Leone| 3434 (50%)| Philippines ~| 785 (80%)
Source: WRI, UNEP 1990, Australian Institute of Marine Science (1992).
Comments: Mangrove forests (swamps) are major ocean-fishery breeding grounds. See a lot more data on mangrove forests in the Fisheries Degradation Review.
Mangrove Swamps -- Asia
Thailand's mangrove forests declined from 3127 km2 in 1975 to 1689 km2 in 1993. (Ref. 36 of (fi00P1)) Another estimate gives a mangrove forest loss rate of 57.2 km2/ year. (Ref. 37 of (fi00P1) -- See a plot in Ref. (fi00P1) covering 1961-96). (la) Comments: Much of this forest land was converted to aquaculture. (la)
In Thailand, shrimp farms covered 1103 km2, or 64% of Thailand's total mangrove forestland in 1987 (fi00P1). (la)
Mangrove Swamps -- Africa
Tanzania has banned the destruction of its remaining 810 km2
of mangrove swamps (fi89L1). (la)
Mangrove Swamps -- Latin America
33% of Ecuador's mangroves have been converted to ponds for shrimp fishing (fi89L1). Shrimp farming has reduced the area of mangrove forests (globally?) by at least 25% (fi94H2). Ecuador has lost 800 km2 of mangrove forests and salt flats to shrimp ponds over the past 23 years (fi94W1). 20% of Ecuador's mangrove forests were converted to shrimp farms during 1979-91 (EDF Letter, 27(1) (1996) p. 7). (la)
Colombia has 3659 km2 of mangroves, of which 80% extend along the Pacific Coast (fi99M6). (la)
Brazil contains the second-largest mangrove area in the world. Possibly over 10,000 km2 of mangrove forests are found along Brazil's coastline (fi01M2). (la)
The Cayapas-Mataje Mangrove Reserve in Ecuador contains 530 km2
on the border with Colombia. Ecuador's other mangrove area is Muisne where 250 km2 of mangroves have been reduced to 6 km2 (fi00M1). (la)
[3] Aquatic Ecosystems Generally
Global estimates of aquatic primary production (PP) (grams carbon/m2/ year), based on 1988-91 FAO data) (Areas are in millions of km2) (fi95P2). (la)
Ecosystem Type~ ~ ~ ~ ~|Area | PP
Open ocean~ ~ ~ ~ ~ ~ ~|332.0| 103
Upwellings~ ~ ~ ~ ~ ~ ~| ~0.8| 973
Tropical shelves~ ~ ~ ~| ~8.6| 310
Non-tropical shelves~ ~| 18.4| 310
Coastal/reef systems~ ~| ~2.0| 890
Rivers and lakes~ ~ ~ ~| ~2.0| 290
Weighted means or total|363.8| 126
The total surface area of the world's oceans is given in Chapter 2 as 361.0 million km2 ((se92Q1) p. 76).
[4] Sea Grass
During 1983-94, more than 900 km2 of sea grasses were destroyed in temperate areas (Ref. 31 of (fi99M1)). (la)
[5] Lakes and Rivers
(See Chapter 2, Section (2-A) [3] Fresh-water-covered land)
One estimate puts the global area (of continental shelves) swept by trawlers at 14.8 million km2 of the sea floor (/year) ((fi98W5), p. 1190). (la)
The total area of the earth's continental shelves is 27.0 million km2
(8.6 million km2 in tropical shelves, and 18.4 million km2
in non-tropical shelves) (fi95P2).
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(9-B) - WETLANDS - [1] Coastal Wetlands, [2] Wetlands in general
[1] Coastal Wetlands
Globally, shrimp ponds have consumed 27,000 km2 of coastal ecosystems (Ref. 14 of (fi97A1)). (la)
Development has destroyed 50% of the world's coastal wetlands (Ref. 48 of (fi94W2)).
Wetlands cover 2.8 million km2 globally (se82P2).
Swamp and Marsh cover 2.0 million km2 (se79A1). Another figure: 2.5 million km2 (se83O1).
Bogs and peat-land cover 1.5 million km2 (se79A1). Another figure: 0.4 million km2 (se83O1).
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(9-C) - LAND USED BY AQUACULTURE - [C1] Global Data, [C2] Asia, [C3] Latin America
[1] Global Data
During 1985-95, 1500 km2 of shrimp farms fell into disuse worldwide (fi98M2). The average aquaculture fishpond is good for about 10 years, but for high-density shrimp ponds, typical pond lifetimes are about 5 years (fi98M2). (la)
Globally, nearly 50,000 shrimp farms cover 9842 km2 of coastal land (fi96W1). (la)
Between 1985-95, 1500 km2 of shrimp farms were abandoned worldwide (Ref. 120 of (fi98M7)). (la)
Globally, shrimp ponds have consumed 27,000 km2 of coastal ecosystems (Ref. 14 of (fi97A1)). (la)
[2] Asia
In Thailand, shrimp farms covered 1103 km2, or 64% of Thailand's total mangrove forestland in 1987. Experiences in Thailand, as well as in Vietnam, show that shrimp farming is unstable in terms of yields. The first few crops normally have high yields because of the quality of the land and water. After a few years Thailand's shrimp farm yields decline because the aquaculture environment - especially the water - deteriorates (00P1). By 1996, Thailand's shrimp farms decreased to 670 km2. As a result of the failed aquaculture, several large tracts of Thailand's eastern and southeastern coasts are deserted (fi00P1). (la)
China plans, by 2010, to double its 1998 area under fish-cultivation to 70,000 km2 (fi98M2). (la) Comments: Compare this area to China's grain area of 857,000 km2
[3] Latin America
Mexico plans to expand its land area used by aquaculture from 200 to 2000 km2. The main wetlands affected will be fragile coastal wetlands like mangroves, lagoons, estuaries, etc. (fi99M6). (la)
33% of Ecuador's mangroves have been converted to shrimp ponds
(fi89L1).
Shrimp farming has reduced Ecuador's mangrove forests by at least 25% (fi94H2).
Ecuador has lost 800 km2 of mangrove forests and salt flats to
shrimp ponds over the past 23 years (fi94W1).
20% of Ecuador's mangrove forests were converted to shrimp ponds
during 1979-91 (EDF Letter, 27(1) (1996) p. 7). (la)
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