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Fisheries of the Mekong: Death by a 1000 Cuts or Just Another Day at the Office?

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Economic development in the Mekong region has brought with it considerable environmental change, with more to follow. The river has already been highly modified by a plethora or perturbations including damming for hydropower and irrigation, disconnection of the flood plains for agriculture and growing urbanization. These have all impacted on the fish and fisheries and delivery of aquatic food products from the system, but the system has to date remained largely resilient, or has it? This paper explores the widespread degradation of the system and how fisheries have responded, looks at future prospects of the river and how the fisheries may be impacts and final examines opportunities which may help to mitigate future development scenarios, especially with respect to hydropower development.

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Fisheries of the Mekong: Death by a 1000 Cuts or Just Another Day at the Office?

  1. 1. Fisheries of the Mekong: Death by a 1000 Cuts or Just Another Day at the Office Vu Vi An, Ian G. Cowx, With support from Kaviphone Phouthavong, Martin Mallen Cooper, Bun Peng, So Nam, Apiradee Hanpongkittikul
  2. 2. Content: 1.Introduction 2.Trend of fisheries in the Mekong Delta 3.Pressures on the fisheries 4.Opportunities and mitigation
  3. 3. 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)
  4. 4. 1. Introduction: -1.0 0.0 1.0 2.0 3.0 4.0 5.0 1-Jan-13 15-Jan-13 29-Jan-13 12-Feb-13 26-Feb-13 12-Mar-13 26-Mar-13 9-Apr-13 23-Apr-13 7-May-13 21-May-13 4-Jun-13 18-Jun-13 2-Jul-13 16-Jul-13 30-Jul-13 13-Aug-13 27-Aug-13 10-Sep-13 24-Sep-13 8-Oct-13 22-Oct-13 5-Nov-13 19-Nov-13 3-Dec-13 17-Dec-13 31-Dec-13 Waterlevel(masl) 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:
  5. 5. - 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:
  6. 6. 2. Trend of fisheries in the Mekong Delta: Fishing habitats (gillnetting) vs Flooding scheme: − Mainstream : 52% − Tribitary : 24% − Flooded rice field : 24% 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0% 20% 40% 60% 80% 100% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Waterlevel(m) Fishingfrequency Mainstream Tributary Rice field Water Level
  7. 7. 2. Trend of fisheries in the Mekong Delta: - Statistics (capture only): Total yield: 1,040,759 t Marine: Fish: 653,600 t Others: 263,184 t Inland : 124,626 t - 67% of households in An Giang province participate in fishing, only 7% are full time fishers. 0 20 40 60 80 100 120 140 160 180 200 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 InlandYield(thousandtons) Year 0 100 200 300 400 500 600 700 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 MarineFishYield(thousandtons) (Sjorslev et al., 2001) Inland: decline 34% or 2.83%/year.
  8. 8. 2. Trend of fisheries in the Mekong Delta: - Fishers' catch monitoring program (FP/MRC): 2007 – 2014 Average daily catch: 5.45kg/day/fisher gillnet. 0 5 10 15 20 25 Jun-07 Nov-07 Apr-08 Sep-08 Feb-09 Jul-09 Dec-09 May-10 Oct-10 Mar-11 Aug-11 Jan-12 Jun-12 Nov-12 Apr-13 Sep-13 Feb-14 Jul-14 Averagecatchrate(kg/day) 2009
  9. 9. 2. Trend of fisheries in the Mekong Delta: 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0 5 10 15 20 25 Waterlevel(m) Catchrate(kg/day) Catch rate Water Level - Fishers' catch monitoring program (FP/MRC): 2007 – 2014 Average daily catch: 5.45kg/day/fisher gill net. 2009
  10. 10. 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 2 4 6 8 10 12 14 16 18 2007 2008 2009 2010 2011 2012 2013 2014 Averagecatchrate(kg/day)
  11. 11. 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
  12. 12. 3. Pressures on the fisheries: 0 50 100 150 200 250 300 350 Alien species Catching spawners Climate change Weak enforcement Population growth Fishing pressure in upstream Pollution Habitat loss Pesticide Hydrology Catching small fishes Dyke construction More fishers Illegal 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:
  13. 13. 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% Aquaculture 1.42% Small business 2.46% Fishing only 22.44% Labor 28.03% Agricultural activities 45.55% Fishers’ likelihoods:
  14. 14. 3. Pressures on the fisheries: % Catch of Exotic Species: 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 2007 2008 2009 2010 2011 2012 2013 %CatchofExoticspecies 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
  15. 15. 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 dominated 2012: High yield rice + Intensive
  16. 16. 3. Pressures on the fisheries: -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 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…
  17. 17. 3. Pressures on the fisheries: Inland fish yield & Rice farming areas: 0 250 500 750 1,000 1,250 1,500 1,750 2,000 0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Ricefarmingarea(thou.Ha) Inlandfishyield(thou.tons) Inland capture yield Rice farming area Negative relationship: p<0.005 Habitat Loss in the MD: Rice…
  18. 18. 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….
  19. 19. 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)
  20. 20. 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
  21. 21. 4. Opportunities and mitigation: Fisheries’ characteristics: Inland Fisheries Marine Fisheries Small-scale gears Large commercial gears Informal 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
  22. 22. 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.
  23. 23. Thank you Especially to AFS and SEAFDEC

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