Fish Diversity in the Mekong River Basin

Valbo‐Jørgensen, John; Coates, David; Hortle, Kent G.

doi:10.1016/b978-0-12-374026-7.00008-5

Cited by 41 publications

(56 citation statements)

References 25 publications

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“…, , Baran , Valbo‐Jørgensen et al. ). Moreover, in other river systems, riverine fishes are found to have homing behavior, and their movements from hundred to thousand kilometers between critical habitats are associated with spawning strategies, for example, Murray Darling golden perch (O'Connor et al.…”

Section: Discussionmentioning

confidence: 99%

Fish assemblage responses to flow seasonality and predictability in a tropical flood pulse system

et al. 2018

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Hydropower dams are looming in the Mekong Basin, affecting river flows that structure aquatic communities. Here, we quantitatively assessed flow seasonality and predictability in three sites located in three rivers displaying a gradient in flow alterations caused by upstream dams and investigated how fish assemblages responded seasonally and inter‐annually to this gradient. By analyzing 7‐yr daily fish and water monitoring data, we found that dams disturbed the natural flow seasonality and predictability. While the river displaying the lower seasonality–predictability was characterized by a distinct seasonal variation in assemblage composition with high species turnover, rivers with stronger flow seasonality–predictability exhibited broadly similar seasonal patterns in fish assemblage composition with low species turnover and regular annual peaks of fish migration. These results challenge the expectation of higher species turnover in systems displaying higher flow seasonality and predictability and may be partly due to the strong adaptation of fish assemblages to these specific systems. By enhancing our understanding of biological systems in the highly seasonal–predictable and aseasonal–unpredictable environments of the lower Mekong system, these findings suggest that hydropower‐related pulsed flows that can mimic as far as possible natural pulsed flows are critical to reduce downstream effects on aquatic organisms.

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Section: Discussionmentioning

confidence: 99%

Fish assemblage responses to flow seasonality and predictability in a tropical flood pulse system

et al. 2018

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“…The dry season fish assemblage of the Songkhram River was mostly dominated by small grey fishes, notably R. dusonensis, a small cyprinid, reducing W statistic to almost zero (Warwick, 1986;Labropoulou and Papaconstantinou, 2005). During this period, large-sized white fishes emigrate from the tributary and return to the mainstream Mekong, especially to deep pools (Baird, 2006;Valbo-Jørgensen et al, 2009;Baran, 2010). In contrast, the reduced W statistic in June in both Mun and Songkhram Rivers was because of a higher proportion of fish larvae of different species rather than smaller-sized species dominating the community.…”

Section: Discussionmentioning

confidence: 99%

“…Correspondence analysis (CA) was applied to log-transformed abundance data to characterize three fish guilds (black, white and grey fish) found in the Mekong River. Black fish are resident and are typically found in floodplain habitats; white fish are longdistance migrants between rivers and floodplains, and grey fish are intermediate, moving locally between the floodplain and dry season refuge (Hortle, 2009b;Valbo-Jørgensen et al, 2009). All statistical analyses were carried out with R software (R Development Core Team, 2012); specifically, 'forams' (Aluizio, 2012) and 'ade4' (Chessel et al, 2012) packages were used for ABC and for ANOSIM and CA, respectively.…”

Section: Data Analysesmentioning

confidence: 99%

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Diversity and Community Structure of Fishes in the Regulated Versus Unregulated Tributaries of the Mekong River

Phomikong

Fukushima

Sricharoendham³

et al. 2014

River Research & Apps

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Diversity and community structure of fishes were studied in three neighbouring tributaries of the Mekong River in Thailand, namely the Mun, Songkhram and Gam Rivers. The rivers are located in the same ecoregion but have contrasting levels of both hydrological regulations and mitigation measures; the Mun River has a hydropower dam with a fish ladder and sluice gates that are opened during the wet season each year, the Gam River has several irrigation dams with a fish ladder at each dam site, and the Songkhram River has no dams along its river course. A total of 124 freshwater fish species were sampled in these rivers from August 2009 to June 2010. Overall species richness was highest in the Songkhram River (112), followed by the Mun (97) and Gam (54) Rivers. Average per site species richness was also significantly different among rivers but not among sampling months. Abundance–biomass comparison plots revealed considerably overlapping distributions of these two metrics from the dry to early rainy seasons in the Songkhram River and, to a lesser extent, in the Mun River. Fish assemblage data were classified into six clusters with similar community structure. Fish assemblages in the Gam River constituted a single cluster, while those in the other two rivers formed multiple clusters depending on the sampling season. The results of the cluster analysis are discussed in relation to the dominance of the three migration guilds (white, black, and grey fishes) of the Mekong River fishes. The effectiveness of the mitigation measures was determined to be limited in alleviating adverse impacts of dams in these tributaries of the Mekong River. Copyright © 2014 John Wiley & Sons, Ltd.

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“…The Mekong River basin is recognised as having unusually high fi sh diversity (Valbo-Jørgensen et al 2009 ) with only the Amazon and the Zaire rivers being comparable (Campbell 2009a ;MRC 2003 ) . The large numbers of fi sh species mean that the effort required understanding and documenting their ecology and behaviour is substantial.…”

Section: Fishmentioning

confidence: 99%