Transcript Status of aquatic biodiversity in the Mekong

Status of Aquatic
Biodiversity in the Mekong
The Second Module of the BDP/MDBC Training Course
21st May 2003
The Mekong River Commission Secretariat Annexes
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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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Mekong River
Basin
Upper Mekong Basin (UMB)
• China
• Myanmar
- 18% of total flow
Lower Mekong Basin (LMB)
• Laos
• Thailand
• Cambodia
• Viet Nam
- 82% of total flow
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Main geographic
regions of LMB
• Mountains of the north
and east
River (water body)
Elevation in meter
0 - 100
100 - 200
200 - 500
500 - 800
800 - 1100
1100 - 1400
1400 - 1800
1800 - 2200
2200 - 2800
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Main geographic
regions
• Mountains of the north
and east
• Isan (Korat) Plateau
River (water body)
Elevation in meter
0 - 100
100 - 200
200 - 500
500 - 800
800 - 1100
1100 - 1400
1400 - 1800
1800 - 2200
2200 - 2800
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Main geographic
regions
• Mountains of the north
and east
• Isan (Korat) Plateau
• Great Lake and
Cambodian plains
River (water body)
Elevation in meter
0 - 100
100 - 200
200 - 500
500 - 800
800 - 1100
1100 - 1400
1400 - 1800
1800 - 2200
2200 - 2800
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Main geographic
regions
• Mountains of the north
and east
• I-san (Korat) Plateau
• Great Lake and
Cambodian plains
• Delta
River (water body)
Elevation in meter
0 - 100
100 - 200
200 - 500
500 - 800
800 - 1100
1100 - 1400
1400 - 1800
1800 - 2200
2200 - 2800
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Highly seasonal
vegetation
Vegetation index
shows vegetation
greening and dryoff.
July
January
April
October
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Diverse
ecosystems
• 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 Agencies
Lao PDR
NAFRI ( LARReC)
Cambodia
Department of Fisheries
Phnom Penh
CNMC
Vientiane
LNMC
TAB
Udon Thani
TNMC
Thailand
Department of Fisheries
(Inland Fisheries R&D Bureau)
VNMC
Ban Me Thuot
HCM City
Viet Nam
Ministry of Fisheries
( RIA.2 and RIA.3)
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Fisheries in the LMB
some 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 LMB
some 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 Estimates



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 Estimates
Consumption per
person (kgs)
Country
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
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2,033
Total
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Inadequate Information on
Aquatic Resources
•
•
•
•
Single ecosystem
Trans-boundary
Dynamic nature
Overlooked in the
past
• Conventional
methodologies give
limited results
• Lack of
communication
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Threats 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 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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Black fish spawning
Feeding
&
Growth
Migration
to
floodplain
Migration
from
floodplain
White fish migrates
and spawns within
river channels
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AMFC/DoF Songkhram
Mekong River
Habitat
availability
(wetlands) in
RED – from
radar
Wetlands
Villages as
blue dots
size = number
of active
fishing
households
Villages
Songkhram River
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Number of species reported to use deep pools at
each station
Chiang Khong
Loei
Khone
Falls
Kratie
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Mekong Flood Plains
give the high fish production
Deep Pools
Provide dry season shelter
Mainstream and Riverside Wetlands
Provide the spawning areas
Fish Migrations
Over 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 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 management is coming in place at all levels
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Capture fisheries outlook
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
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Capture 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 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 Mitigation
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 level
Downstream: Anoxic water outlet, changed water temperature,
lack of sediment, etc.
Potential Effect:
Loss of income, employment and food security, biodiversity.
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MITIGATION METHODS:
Downstream effects:
Changed water intake to turbines;
In-reservoir:
Bubbling systems
Improved management of water level, etc.
Passing the dam: Fishways
AIR BUBBLING SYSTEM
(Champagne Method)
Destratification of
reservoirs
Diffusers
Dam
North Pine Reservoir
Area: 22 Km2,
Depth: 35 meter
Pump house
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Convention on Biological Diversity
“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 Fisheries
o
o
Precautionary approach
Impacts of introductions often
irreversible and unpredictable
o
“…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 Status
o
o
o
o
Valid ecosystem concerns
Adequate legal instruments,
policies and recommendations
Incomplete implementation
Need to enhance
implementation and monitoring
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Present Status
o
o
o
o
Existing knowledge needs to
be consolidated
Capacity to implement is
asymmetric
Implementation of policies
needs support and monitoring
Institutional cooperation
through Networking
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Issues for BDP
•
Achieving sustainability will require an
integrated approach to managing water, land,
and ecosystems
• Protecting ecosystems requires integrating
biodiversity conservation and ecosystem
management into local and national economies
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Issues for BDP
•
Participatory ecosystem-based catchment
management is a fundamentally new approach
to using, developing, and conserving water
resources
• Allowing ecosystems to perform their
functions requires that users let certain
amounts of water stay within the ecosystems
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MITIGATION
Passing the dam:
Fishways
Vertical slot fishway, 7m
Fish lift, 15 m
Tonle Sap River
5,000 per 24 hrs
3,800 fish per 24 hrs
50,000 fish per minute
*********
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Chumnarn Pongsri
Mekong River Commission Secretariat
[email protected]
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