1. Bioassessment in the lower Mekong River: technology transfer to a developing region Ian Campbell 1 and Bruce Chessman 2 1 Rhithroecology, Blackburn South, Victoria, Australia 2 Chessman Ecology, Pymble, New South Wales, Australia

2. Multi-national project of the Mekong River Commission to develop and implement biomonitoring of the lower Mekong River system (2003-2008)

3. Mekong River World’s 12th longest river (4350 km) Watershed of 795,000 km 2 Average discharge 16,000 m 3 /s Flows through 6 nations Drains one of the world’s most biodiverse regions Yields 4.5 million tonnes of fish and other aquatic produce per annum Supports livelihoods of ~ 40 million people

4. Need for a biomonitoring program Mekong River Commission established in 1995 to facilitate joint management of water resources by lower basin countries (downstream of China) Mekong Agreement 1995 – article 3 “ To protect the environment, natural resources, aquatic life and conditions, and ecological balance of the Mekong River Basin from pollution and other harmful effects resulting from any development plans and uses of water and related resources in the basin” Extensive hydrographic and physical-chemical monitoring by 2002 but no biological monitoring Therefore uncertain to what degree the objective of article 3 was being achieved

5. Challenges Co-ordination among MRC and four lower basin countries Regional experience with biological sampling and identification but no established bioassessment methodology Development of a pragmatic approach aligned to the Mekong Agreement objective Building of regional capacity and program ownership

6. Project approach Project team including – Aquatic scientists from Cambodia, Lao PDR, Thailand and Vietnam – 2 international mentors / facilitators (Vince Resh and Bruce Chessman) Pilot survey in 2003 to select biota for inclusion and test sampling methods Annual dry-season surveys from 2004-2007 to develop assessment methods and rate site condition

7. Assessment methodology Four biotic groups – Littoral macroinvertebrates – Benthic macroinvertebrates – Zooplankton – Littoral diatoms

8. Assessment metrics Chosen to quantify the concept of ‘harmful effects of development’ as expressed in the Mekong Agreement rather than for correlation with human disturbance gradients – Number of taxa (reduction = harm) – Number of individuals (reduction = harm) – Pollution tolerance index (increase = harm)

9. Tolerance indices Site Disturbance Score (visual rating based on anthropogenic activities and alteration on a scale of 1-3) Tolerance scores for diatom and invertebrate taxa developed as abundance-weighted averages of Site Disturbance Scores at sites of occurrence Average tolerance score per taxon (ATSPT) calculated for each sample Higher scores indicated a more tolerant fauna

10. Criteria for reference sites pH > 6.5 and < 8.5 Electrical conductivity < 700 μ S/cm Dissolved oxygen > 5 mg/L No major dams or cities within 20 km upstream of site Not affected by inter-basin water transfers Site Disturbance Score < 1.67 on a scale of 1-3

11. Reference sites 14 of 51 sites met all criteria and were selected as reference sites 4 in Cambodia, 8 in Lao PDR, 1 in Thailand, and 1 in Vietnam No significant relationships of metrics to altitude or river width at reference sites 10 th and 90 th percentile values of metrics at reference sites used as assessment criteria

12. Report card rating scheme Guidelines for each biological assemblage – Richness > 10 th percentile of reference site values – Abundance > 10th percentile of reference site values – ATSPT < 90 th percentile of reference site values Total of 12 indicators (3 metrics x 4 assemblages) Site rating – Excellent – 10-12 indicators meet guideline – Good – 7-9 indicators meet guideline – Moderate – 4-6 indicators meet guideline – Poor – 0-3 indicators meet guideline

13. Results 77 sampling events (51 sites, some sampled > once) – 28 excellent – 32 good – 17 moderate – 0 poor AssemblageNo. of taxaNo. of individuals Diatoms174218, 326 Zooplankton20786,076 Littoral invertebrates 35981,499 Benthic invertebrates 17623,785

14. Conclusions Biological condition of the lower Mekong compared favorably with that of other large rivers in both developed and developing world Little heavy industry and urban wastewater discharged mostly to wetlands rather than directly to the river Generally low levels of pesticides, metals and organic contaminants Significant nutrient enrichment in the delta results from high populations, intensive agriculture and in-stream aquaculture, but NOT industrial development

15. Outputs Sampling manual Invertebrate taxonomic key 5 project reports Report card Available from Mekong River Commission website

16. Reflections Involvement of regional expertise and capacity building were major contributors to success Since 2010 biomonitoring has been conducted by agencies of the four lower Mekong countries Vince brought invaluable experience in implementing biomonitoring in developing countries (especially in Africa and Asia), and in engagement, mentoring and teaching, and boundless enthusiasm! Exclusion of fish was disappointing given their importance to the basin economy but was logistically impractical However MRC has a separate Fisheries Programme

17. Thank you Acknowledgments Supatra Parnrong Davison Pham Anh Duc Sok Khom Tatporn Kunpradid Jane Lee Nguyen Thi Mai Linh Monyrak Meng Bounnam Pathoumthong Yuwadee Peerapornpisal Vince Resh Niane Sivongxay Lieng Sopha Sutthawan Suphan Chanda Vongsambath And many other helpers