Fisheries of the Mekong: Death by a 1000 Cuts or Just Another Day at the Office?
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Transcript of Fisheries of the Mekong: Death by a 1000 Cuts or Just Another Day at the Office?
Fisheries of the Mekong:Death by a 1000 Cuts or
Just Another Day at the OfficeVu Vi An, Ian G. Cowx,
With support from Kaviphone Phouthavong, Martin Mallen Cooper, Bun Peng,
So Nam, Apiradee Hanpongkittikul
Content:
1. Introduction
2.Trend of fisheries in the Mekong Delta
3.Pressures on the fisheries
4.Opportunities and mitigation
1. Introduction:
− Total yield in the LMB: over 2.5 million tons (19% of OAAs): Thailand: 36%; Viet Nam: 33%; Cambodia: 23%; and Laos: 8%. Total value: about US$6.5 billion/year.
− Per capita consumption average: about 33.7kg/person/year(VN: 39kg; Cam: 36.8kg; Thailand: 29kg; Laos: 28.6kg).
− Fish diversity: 800 – 1200 species with 30+ of high commercial importance.
− At least 7 giant fish: Mekong giant catfish (P. gigas), giant pangasius (P. sanitwongsei), giant barb (C. siamensis), striped barb (P. jullieni) + Mekong dolphin (O. brevirostris)…
(Hortle, 2007; Hogan, 2011)
1. Introduction:
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Wat
er le
vel (
m a
sl)
Vietnamese Mekong Delta: Tan Chau station
Up to 50%
Concentration of fish in permanent water bodies
Adults movement + Drift of larvae to feeding areas on the flooded areas
Movement to dry season refuges, and dispersal
DRY Season:FLOOD Season:
- White fish (undertaking long distance migrations): 36% of capture;
- Black fish (floodplain resident fish, limited lateral migrations): 50%of capture;
- Grey fish: 14 % of capture.
− Fish migtate all seasons of year.
1. Introduction:
2. Trend of fisheries in the Mekong Delta:Fishing habitats (gillnetting) vs Flooding scheme:− Mainstream : 52%− Tribitary : 24%− Flooded rice field : 24%
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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Wat
er le
vel (
m)
Fish
ing
freq
uenc
y
Mainstream Tributary Rice field Water Level
2. Trend of fisheries in the Mekong Delta:- Statistics (capture only):
Total yield: 1,040,759 tMarine:
Fish: 653,600 tOthers: 263,184 t
Inland : 124,626 t
- 67% of households in An Giang province participate in fishing, only 7% are full time fishers.
020406080
100120140160180200
2000
2001
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2008
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2010
2011
Inla
nd Y
ield
(tho
usan
d to
ns)
Year
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70020
00
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2007
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2009
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2011M
arin
e Fi
sh Y
ield
(tho
usan
d to
ns)
(Sjorslev et al., 2001)
Inland: decline 34%or 2.83%/year.
2. Trend of fisheries in the Mekong Delta:- Fishers' catch monitoring program (FP/MRC): 2007 – 2014
Average daily catch: 5.45kg/day/fisher gillnet.
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Jul-1
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Aver
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h ra
te (k
g/da
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2009
2. Trend of fisheries in the Mekong Delta:
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h ra
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g/da
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Catch rate
Water Level
- Fishers' catch monitoring program (FP/MRC): 2007 – 2014Average daily catch: 5.45kg/day/fisher gill net.
2009
2. Trend of fisheries in the Mekong Delta:2. Trend of fisheries in the Mekong Delta:- Fishers’ catch monitoring program (FP/MRC): 2007 – 2014
Decline: 8.5kg/day (2007) to 6.4kg/day (2014).
0
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2007 2008 2009 2010 2011 2012 2013 2014
Aver
age
catc
h ra
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g/da
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3. Pressures on the fisheries:Major threats to inland fisheries include:
• Over-fishing + destructive fishing methods
• In-channel barriers (Blocking of fish migration routes)
• Land use changes (habitat loss)
• Industrial and urban pollution
• Urbanisation • Agricultural pollution: pesticides
• Run-of-river abstractions • Mining pollution• Irrigation • Sediment mining• Impoundments • Climate change• Aquaculture linked to
invasive species• Hydrological changes (e.g.
timing and extent of flooding)• Flood mitigation measure • Hydropower
3. Pressures on the fisheries:
0 50 100 150 200 250 300 350
Alien speciesCatching spawners
Climate changeWeak enforcementPopulation growth
Fishing pressure in upstreamPollution
Habitat lossPesticide
HydrologyCatching small fishes
Dyke constructionMore fishersIllegal gears
Frequency (# fishers)
34.5%
31.7%
11.4%
6.6%
4.8%
4.0%
3.4%
1.0%
0.9%
0.5%
0.4%
0.3%
0.3%
0.1%
Fishers’ perception:
3. Pressures on the fisheries:Illegal gears in the MD:
- Fishing gears: >120 gear types: small and simple: Traps; Gillnetting; Hook and lines, Towing/ dragging; Castnet, Scooping, Collection by hand, Liftnet; Bagnet …
- Illegal gears: Fishing with electricity and chemicals; Gears with small mesh-size.
Motobyke taxi
0.09%
Aquaculture1.42% Small
business2.46%
Fishing only
22.44%
Labor28.03%
Agricultural activities45.55%
Fishers’ likelihoods:
3. Pressures on the fisheries:
% Catch of Exotic Species:
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2007 2008 2009 2010 2011 2012 2013
% C
atch
of E
xotic
spec
ies
Year
Including 9 exotic species: Pterygoplichthys disjunctivus, Colossoma macropomum, Oreochromis sp., Hypophthalmichthys molitrix, Clarias gariepinus, Labeo rohita, Cyprinus carpio, Ctenopharyngodon idella, Hypophthalmichthys nobilis.
Exotic species: Fishers’s cacth monitoring program FP/MRC
3. Pressures on the fisheries:Habitat Loss in the MD: Rice…
Vo Tong Xuan (1975) Wyatt et al. (2012)
Rice farming: Change from Floating rice (6 months/crop , ~2tons/ha/ crop, 1 crop/year only, planting during flooding season) to TN rice –“God of agriculture rice” - (3 months/crop, 5-7 tons/ha/crop, up to 3 crops/year, planting in any season).
1975: Floating rice dominated2012: High yield rice +
Intensive
3. Pressures on the fisheries:
-0.5
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1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec
3rd rice crop:
Habitat Loss in the MD: Rice…
1st rice crop: plant earlier by pumping water out…
3. Pressures on the fisheries:
Inland fish yield & Rice farming areas:
0
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1,000
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1,750
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0
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160,00019
9519
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0020
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1120
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Rice
farm
ing
area
(tho
u. H
a)
Inla
nd fi
sh y
ield
(tho
u. to
ns)
Inland capture yield
Rice farming area
Negative relationship: p<0.005
Habitat Loss in the MD: Rice…
3. Pressures on the fisheries:Water control structure:• Every dot is a registered
water control structure.• Loss of connectivity = loss
of productivity in floodplain/riverine fisheries.
The MRC water structures map
JICA/MARD’s project: in 7 coastal provinces. Structural: Saline intrusion prevention sluice gate contruction; Seashore protection and improvement. Non-Structural: Cropping calendar adjustment and improvement….
3. Pressures on the fisheries:Hydropower dams:9 planned dams on LMB
(mainstream) – two under construction.
23 existed dams (> 20 MW) on tributaries.
Many more tributary dams are projected or under construction.
- Cambodia: 20 projects (1 Ope; 1 Und; 0 Lic; 18 Plan).
- Laos: 100 projects (21 Ope; 25Und; 16 Lic; 38Plan).
- Thailand: 7 Ope prjects.- Viet Nam: 15 projects (13 Ope; 1 Und;
0 Lic; 1 Plan). Niel et al. (2014)
3. Pressures on the fisheries:Linkage Between Drivers and Impacts:
Hydropower Projects Other exogenous factors
Changes in River Flows, Sediment Transport, and
Water Quality
Obstructions in Fish Migration Routes &Habitat Connectivity
Changes in Fish Habitat Quality, Quantity, &
Productivity
Fisheries Impacts
4. Opportunities and mitigation:Fisheries’ characteristics:
Inland Fisheries Marine FisheriesSmall-scale gears Large commercial gearsInformal Formal (e.g. licenced) Dispersed, often hidden by geography/vegetation
Visible, large gears at open sea
Landings dispersed and informal
Landing centralized and visible
Part-time fishing dominates (e.g. mixed farming/fishing lifestyles on river floodplains)
Professional fishing dominates, i.e. very few part-time fishers
Most catch consumed domestically
Most is exported out of the community of capture
Many people participate Few people participate
Modified from: FAO RAP Publication 2002/11
4. Opportunities and mitigation:Mitigation measures:
Mitigation measures to ameliorate likely impacts focus on:
• in-take and outfall locations;
• fish passage facilities – upstream and downstream,
• ‘Friendly’ turbine design;
• measures to ameliorate the potential impact of depleted reaches – allocation of flows;
• replacement of lost fisheries – aquaculture and stocking;
• need habitat connectivity to complete fish life cycle;
• fish friendly irrigation scheme.