Abstract

The report is the first ever large-scale study to consider both spatial and temporal variations of fish abundance and diversity in the LMB, using the MRC’s long-term fisheries monitoring data. The monitoring was conducted daily between 2007 and 2018 by professional fishers at 38 stations along the Mekong mainstream and its major tributaries. But only 25 sites were selected for the study due to incomplete data. Eleven of the 25 monitoring stations were in Cambodia, four in Lao PDR, and five each in Thailand and Viet Nam. The study found 617 fish species, belonging to 21 order and 80 families in the LMB from 2007 to 2018. Some 37,530,460 individuals, corresponding to 1,095,848 Kg of fishes were collected. Temporally, both fish diversity and catch have increased during the survey period in the Tonle Sap and the Mekong upstream in southern Laos and Thailand, informing the high diversity of these areas and that sampling effort is still growing.

Highlights

  • The monitoring stations were grouped based on Biological Resource Assessment (BioRA) Zones following the Mekong River Commission (MRC) Council Study: Zone 2 (3 stations from Nam Beng to upstream of Vientiane), Zone 3 (6 stations from Vientiane to Nam Kam), Zone 4 (3 stations from Nam Kam to Kratie), Zone 7 (7 stations in the Tonle Sap Great Lake and Tonle Sap River), Zone 8 (5 stations in the Mekong Delta), and Zone 3S (3 stations in Sekong, Sesan and Sre Pok rivers)

  • This study indicated that fish communities of Zones 4 and 3S at the upper part of Cambodia was associated with a high Dissolved Oxygen (DO) and water levels, opposite to that of Zone 8 in the Viet Nam Mekong Delta

  • In the Lower Mekong Basin (LMB), richness and diversity increased with high DO, but abundance decreased because fish were widely dispersed and difficult to capture (Ngor et al, 2018)

Read more

Summary

Introduction

This report describes the status and trends of fish abundance and diversity from the Mekong River Commission (MRC). The Fish Abundance and Diversity Monitoring (FADM) Programme in the Lower Mekong Basin (LMB) is a routine, artisanal fisheries monitoring programme to determine both status and trends of fish abundance and its diversity in the LMB through temporal and spatial variation. The study aims to: (i) evaluate the contribution of fish species and guilds to the fisheries of the LMB; (ii) evaluate the status and trends in fish catch; (iii) monitor spatial and temporal patterns in fish abundance and diversity; and (iv) assess fish community patterns and their relationship with environmental factors

Key findings
Conclusion and recommendations
MONITORING STATIONS
FISHER SELECTION
SAMPLING TECHNIQUES
DATA COLLECTION
Catch rate, Catch Per Unit Effort (CPUE)
Fish species richness and diversity in the LMB
Temporal change in fish diversity and abundance in the LMB
Patterns of fish community in the LMB
Abundance/Biomass Comparison (ABC) Curve
Relationship between fish species and environmental factors
Basin-wide fish catch
Rank species relative abundance distributions
Dominant species in relationship with relative abundance
Relationship between relative abundance and relative biomass in LMB
Fish Abundance-Biomass Curves (ABC) in the LMB The relative Abundance-Biomass
Fish Catch Rate (CPUE)
Spatial Patterns of fish richness and abundance LMB species richness
Temporal patterns of fish species richness and abundance in the LMB
Patterns of fish communities in the Lower Mekong River (LMR)
G4 G4 G4 G6 G6 G1 G11 G3 G11 G11 G3
G8 G11 G7 G7
Relationship between fish diversity and abundance with key environmental factors in the LMB
FISH DIVERSITY IN THE LMB
STATUS OF FISH CATCHES IN THE LMB
FISH ASSEMBLAGE AND THE INFLUENCE OF ENVIRONMENTAL FACTORS
The status and trends of fish catches in the LMB
Spatial and temporal changes in fish diversity and abundance
Fish community patterns and their relationship with key environmental factors
10 Cambodia Stung Treng
20 Lao PDR Luangphrabang Pak Ou
26 Lao PDR Xekong 27 Thailand Loei
32 Viet Nam An Giang
G3 G7 G3
G2 G7 G7 G7 G7 G10 G10 G1 G4 G1 G3 G1 G1 G3 G10 G3
G10 G7 G5 G7 G7 G7 G10 G10 G7 G10 G10 G10 G3 G6 G1 G6 G6 G6 G1 G6 G6 G6 G10
G10 G10 G7 G11 G10 G10 G3 G3 G2 G2 G5 G5 G5 G4 G4 G4
G11 G3 G3 G3 G3 G11
G7 G7 G10 G5 G10 G4 G4 G4 G1 G1 G1 G7 G7 G10 G10 G1 G1 G1 G11 G11 G1 G11 G6
G4 G3 G2 G4 G4 G11 G2 G11 G2 G8 G2
G4 G4 G4 G4 G1 G7 G10 G7
G4 G3 G3 G4 G3 G4 G4 G5 G4 G1 G1 G1 G10 G4 G4 G4 G4 G4 G4 G10 G4 G4 G4
G1 G1 G1 G1 G1 G1 G1 G1 G10
Findings
G3 G3 G3 G10 G10 G10 G7

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.