status of aquatic biodiversity in the mekong

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Status of Aquatic Status of Aquatic Biodiversity in the Biodiversity in the

MekongMekong

The Second Module of the BDP/MDBC Training The Second Module of the BDP/MDBC Training CourseCourse

2121stst May 2003 May 2003

The Mekong River Commission Secretariat The Mekong River Commission Secretariat AnnexesAnnexes

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“..the Mekong River Basin and

the related natural resources and environment are natural assets

of immense value…”

1995 Mekong Agreement

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Upper Mekong Basin (UMB)

• China• Myanmar

- 18% of total flow

Lower Mekong Basin (LMB)

• Laos• Thailand• Cambodia• Viet Nam

- 82% of total flow

Mekong Mekong River BasinRiver Basin

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• Mountains of the north and east

Main geographic Main geographic regions of LMBregions of LMB

2200 - 28001800 - 22001400 - 18001100 - 1400800 - 1100500 - 800200 - 500100 - 2000 - 100

Elevation in meter

River (water body)

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• Mountains of the north and east

• Isan (Korat) Plateau

Main geographic Main geographic regionsregions

2200 - 28001800 - 22001400 - 18001100 - 1400800 - 1100500 - 800200 - 500100 - 2000 - 100

Elevation in meter

River (water body)

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• Mountains of the north and east

• Isan (Korat) Plateau

• Great Lake and Cambodian plains

Main geographic Main geographic regionsregions

2200 - 28001800 - 22001400 - 18001100 - 1400800 - 1100500 - 800200 - 500100 - 2000 - 100

Elevation in meter

River (water body)

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• Mountains of the north and east

• I-san (Korat) Plateau

• Great Lake and Cambodian plains

• Delta

Main geographic Main geographic regionsregions

2200 - 28001800 - 22001400 - 18001100 - 1400800 - 1100500 - 800200 - 500100 - 2000 - 100

Elevation in meter

River (water body)

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JulyOctober

JanuaryAprilJuly

Highly seasonal vegetation

Vegetation index shows vegetation greening and dry-

off.

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Diverse Diverse ecosystemsecosystems

• tropical rainforest, deciduous forest, dry woodland, grassland, wetland, mangroves

• wetlands of Great Lake and floodplains

• Biodiversity

•>1200 species of fish

•Abundant water birds

•Rare species Irrawaddy dolphin, Javan rhinoceros

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Working with Fisheries Working with Fisheries AgenciesAgencies

CambodiaDepartment of Fisheries

Lao PDR NAFRI ( LARReC)

Thailand Department of Fisheries

(Inland Fisheries R&D Bureau)

Viet NamMinistry of Fisheries( RIA.2 and RIA.3)

Phnom Penh Vientiane

Udon Thani Ban Me ThuotHCM City

TAB

CNMC LNMC

TNMC VNMC

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Fisheries in the LMBFisheries in the LMBsome datasome data

Fisheries in the LMBFisheries in the LMBsome datasome data

- 1200 - 2000 fish species – possibly 2nd richest river system in the World

- 80% of people involved (full- and part-time)

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Fisheries in the LMBFisheries in the LMBsome datasome data

Fisheries in the LMBFisheries in the LMBsome datasome data

- Catch is about 2% of total world capture fishery, marine and freshwater

- Value about US$1,400 million direct value only

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Fish Production Fish Production EstimatesEstimates

Fish Production Fish Production EstimatesEstimates

Total inland fish & OAAs 2.0 million tonnes Capture Fisheries 1.75 Mt Aquaculture 0.25 Mt

Estimation methods

1. Consumption studies(above figures)

2. Wetland productivity( 150 kg/ha/yr)

3. Landing surveys(difficult)

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Fish Production Fish Production EstimatesEstimates

CountryConsumption per person (kgs)

Total consumption (‘000 tonnes)

Cambodia 47 (10-89) 508

Lao PDR 26 (17-36) 133

Thailand 35 (20-41) 795

Viet Nam 33 (15-60) 597

Total 36 2,033

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Inadequate Information on Inadequate Information on Aquatic ResourcesAquatic Resources

Inadequate Information on Inadequate Information on Aquatic ResourcesAquatic Resources

• Single ecosystem• Trans-boundary• Dynamic nature• Overlooked in the

past • Conventional

methodologies give limited results

• Lack of communication

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ThreatsThreats on Aquatic Resources on Aquatic ResourcesThreatsThreats on Aquatic Resources on Aquatic Resources

• Growing population ~ 2%

• ~ 2025…~ 90 millions

• Natural change of habitats

• Human interventions: fishing pressure, development of water management schemes, pollution, etc.

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Threats to the Fisheries Sector:General: Habitat Destruction

Constraints to migration

Pollution (in future)

Exotic fish species

Local: High Fishing Effort

Illegal fishing methods

Mitigation:Cross-sectoral: Integrated water use planning

Information on resources

Fisheries Sector:Regional management

National protection

Local co-management

Indigenous fish aquaculture

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Flood PulseFlood PulseFlood PulseFlood Pulse

River fishes depend upon flooding for their production and diversity, because flooding creates a productive habitat, and provides nutrient-rich silt.

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Migration to

floodplain

Migration from

floodplain

White fish migrates and spawns within river channels

Black fish spawning

Feeding

&

Growth

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AMFC/DoF Songkhram

Habitat availability (wetlands) in RED – from radar

Villages as blue dots size = number of active fishing households

Mekong River

Songkhram River

Wetlands

Villages

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Number of species reported to use deep pools at each station

Kratie

Loei

Chiang Khong

Khone

Falls

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Mekong Flood Plains give the high fish production

Deep PoolsProvide dry season shelter

Mainstream and Riverside Wetlands

Provide the spawning areas

Fish MigrationsOver 500-1000 km or more bring fish

- from the spawning areas upstream into the flood plains during the rainy season;

-Back up into the deep pools in the mainstream when the rain stops and the flood plains dry out;

- Out to spawn in the mainstream and the riverside wetlands when the rain starts again

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Migration patterns for Helicophagus waandersii

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Capture fisheries outlookCapture fisheries outlookCapture fisheries outlookCapture fisheries outlook

Opportunities: The Mekong aquatic ecosystems and

fisheries are in good shape The fisheries are (locally) under stress,

but no indication that maximum yield has been attained

The knowledge base for informed manage-ment is coming in place at all levels

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Opportunities: Increased recognition by politicians of

inland fisheries importance and awareness of problems

Enabling institutional frameworks for joint management, co-management and integrated management in place

Enhanced fisheries (stocking) feasible through co-management initiatives

Capture fisheries Capture fisheries outlookoutlook

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Capture fisheries outlookCapture fisheries outlookCapture fisheries outlookCapture fisheries outlook

Threats from within the sector: Use of habitat destructive fishing

methods Unsustainable fishing practices:

- fishing in sensitive areas- fishing at sensitive times- targetting juveniles

Badly considered species introductions

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Capture fisheries outlookCapture fisheries outlookCapture fisheries outlookCapture fisheries outlook

Threats from outside the sector: Habitat alterations Physical barriers to fish migration Changes in quality and quantity of water

in sensitive habitats (pollution/flooding) The fisheries ”message” does not get

across to planners in more powerful sectors

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WMD Impacts and WMD Impacts and MitigationMitigation

WMD Impacts and WMD Impacts and MitigationMitigation

Direct impacts on fish passage, barrier effect Fishways, or other fish passage measures

Water quality effects due to stratification, toxicity and reduced productivity Destratification or multi-level offtakes

Hydrological impacts, impacts on fish behaviour, habitat etc. Riparian flows, regulating ponds

Trapping of nutrients, organic material and sediment, loss of productivity Not mitigated at present, Research Needed

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MITIGATION OF EFFECTS OF WATER MANAGEMENT ON FISHERIES

Structures: Dams, dikes, weirs, reservoirs

Problems for fisheries:Dams: Hindrance to fish migrations, Reservoirs: Still water body, anoxic bottom conditions,

rapidly changing water levelDownstream: Anoxic water outlet, changed water

temperature, lack of sediment, etc.Potential Effect:

Loss of income, employment and food security, biodiversity.

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AIR BUBBLING SYSTEM

(Champagne Method)

Destratification of reservoirs

North Pine Reservoir

Area: 22 Km2,

Depth: 35 meter

 MITIGATION METHODS:Downstream effects: Changed water intake to turbines;In-reservoir: Bubbling systems

Improved management of water level, etc.Passing the dam: Fishways

Diffusers

Pump house

Dam

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Convention on Biological Convention on Biological DiversityDiversity

Convention on Biological Convention on Biological DiversityDiversity

“Prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species” (article 8 h)

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FAO - Responsible FisheriesFAO - Responsible FisheriesFAO - Responsible FisheriesFAO - Responsible Fisherieso Precautionary approacho Impacts of introductions often

irreversible and unpredictableo “…the introduction of aquatic organisms

for aquaculture should be considered as a purposeful introduction into the wild…”

o Minimise risk of environmental effects

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Present StatusPresent StatusPresent StatusPresent Status

o Valid ecosystem concernso Adequate legal instruments,

policies and recommendations

o Incomplete implementationo Need to enhance

implementation and monitoring

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Present StatusPresent StatusPresent StatusPresent Status

o Existing knowledge needs to be consolidated

o Capacity to implement is asymmetric

o Implementation of policies needs support and monitoring

o Institutional cooperation through Networking

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Issues for BDPIssues for BDP

• Achieving sustainability will require Achieving sustainability will require an integrated approach to managing an integrated approach to managing water, land, and ecosystemswater, land, and ecosystems

• Protecting ecosystems requires Protecting ecosystems requires integrating biodiversity conservation integrating biodiversity conservation and ecosystem management into local and ecosystem management into local and national economiesand national economies

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Issues for BDPIssues for BDP

• Participatory ecosystem-based Participatory ecosystem-based catchment management is a catchment management is a fundamentally new approach to using, fundamentally new approach to using, developing, and conserving water developing, and conserving water resourcesresources

• Allowing ecosystems to perform their Allowing ecosystems to perform their functions requires that users let certain functions requires that users let certain amounts of water stay within the amounts of water stay within the ecosystemsecosystems

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 MITIGATION

Passing the dam: Fishways

Vertical slot fishway, 7m

5,000 per 24 hrs

Fish lift, 15 m

3,800 fish per 24 hrs

Tonle Sap River

50,000 fish per minute

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Chumnarn PongsriChumnarn Pongsri

Mekong River Commission SecretariatMekong River Commission Secretariat

Chumnarnp@mrcmekong.org