By: Douangkham Singhanouvong

Deputy Director of LARReC

Living Aquatic Resources Research Center (LARReC)))

American Fisheries society Conference16-20 August 2015, Portland USA

1. Background2. Methodology3. Result 4. Conclusion

Important fish migration take place in the Lower Mekong River of southern Lao PDR during both the dry and wet season.

There are several fish species that migrate in both up and downstream directions from the South to North all both seasons.

Lack of information about fish migration, fish abundant and almost no quantitative data has been available for future baseline monitoring.

So, the Lee trap research has been started since 1993 - 98, supported by IDRC, Canada.

From 2007 to 2013 the study was supported by Fisheries Programme of Mekong River Commission ( MRC)

Khong district

(Or Khong Island)

1.1 Location of study

Water Fall

1.2 Hoosom Yai channel (Con’t)

Lee traps or Bamboo -wing traps are one of the most popular fishing gears in Laos especially in Southern part. They are made from Bamboo with the length of 8 to 10 meter and wide around 1.5 meter. These gears are mainly used in the wet season, set in appropriate channels and placed in position to intercept the nocturnal fish movement. Lee trap are also placed directly in the current with half of the bamboo matting structure in the water, and half out the water. These traps are caught mainly fish that move up stream, when they could not pass to the strength current then they flow down into the Lee trap (Singhanouvong. D, 1994).

An overall objectives To provide a time series of relative abundance

estimate for migratory white fish in the lower Mekong River in order to monitor the effects of fisheries management and basin development activities.

1) To monitor and determine status and trends in fisheries resources in terms of diversity and relative abundance in the Khone Falls through temporal and spatial variation. 2) To support valuable information on fisheries resources for fisheries management and impacts assessment purposes.

2.1. Data collection:-Started from the end of May to the September every year

-Count the number of fishing gear (lee trap) that are working.

- Count the number and weigh of each species caught for important species.

- Measurements of the mean flow volume (m3/s) passing down HSY

- CPUE data recorded as kg/trap/nightMeasured and weighted a fish

Year May June July August Sept

2007 17 17 0 0 0

2008 0 10 9 5 4

2009 17 18 10 7 7

2010 17 18 10 7 7

2011 21 22 10 2 3

2012 22 20 16 10 9

2013 21 21 16 7 6

3.1. Catch Per Unit Effort and trend ( 2007 to 2013)

3.2. CPUE top five species and trend (2007-2013)

Labeo chrysophekadion Pangasius larnaudiei

Hemisilurus mekongensis.Bagarius yarrelli

Hemisilurus mekongensis

3.3. Fish biodiversity

3.4. Total fish landing by year (kg)

3.5. Total catch by month and year (kg)

Year May June July August Sep

2007 100,7 557 0 0 0

2008 0 682 1,176 887 69

2009 1,013 2,219 660 365 339

2010 80 594 2,214 974 501

2011 202 654 468 167 76

2012 544 1,000 429 449 284

2013 73 1,091 543 309 124

3.6. total catch by feeding type (%)

Carnivorous

Herbivorous Omnivorous

Osteochilus microcephalus

Labeo chrysophekadion

Botia modesta

Pangasius conchophilus

Micronema sp

3.7. total catch by ecological characteristic

White Fish

Gray Fish Black Fish

Estuary Fish

• The daily catches in 2012 and 2013 were increased especially during the high flow late May and Early June.

• The number of fish species and quantities of fish catch changes from May to September.

• The main species reported in the catch were :Pangasius larnaudiei, Bagariusyarrelli, Labeo chrysophekadion, Pangasius conchophilus and Hemisilurus mekongensis.

• The white fish were the dominant species and follow by grey fish, black fish and estuary fish

• The total catch from 2007 to 2013 varied depending on water flows.

• The highest catches were in 2009 and 2010 and the lower catches were 2007 and 2011.

• The rainfall and water level were perhaps the main factors affecting fish catches.

• The Length frequencies of the main five species shows not much changed in term of length during 2008 to 2013.

• The results that we have gathered can now be applied to the fisheries resources management.

• This management is important for the Lower Mekong Basin development planning purposes.