scholarly journals Fishing Methods Matter: Comparing the Community and Trait Composition of the Dai (Bagnet) and Gillnet Fisheries in the Tonle Sap River in Southeast Asia

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1904
Author(s):  
Suzanne J. Kelson ◽  
Zeb Hogan ◽  
Christopher L. Jerde ◽  
Sudeep Chandra ◽  
Peng Bun Ngor ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Resource Selection ◽  
Flood Pulse ◽  
Target Groups ◽  
Main River ◽  
Tonle Sap ◽  
Lower Mekong Basin ◽  
Specific Trait ◽  
Species Specific ◽  
Catch Composition

The Tonle Sap Lake and River ecosystem in the Lower Mekong Basin of Southeast Asia is one of the most productive inland fisheries globally but is currently threatened by overfishing, dam construction, and climate change. We compare the catch composition and amount from 2007–2013 of two fishery gear types, the bagnets of the largest commercial fishery, the Dai fishery, and gillnets, which are deployed ubiquitously by independent fishers. We found that the two methods captured a similar number of genera (81 and 88 in the Dai and gillnet). Catches of both fisheries were dominated (>75%) by three genera that migrate longitudinally, Henicorhynchus, Labiobarbus, and Paralaubuca. The catch of the Dai fishery followed annual variation in the flood pulse extent, but the gillnet catch did not. We used resource selection ratios to quantify selection pressure by the gillnet fishery, relative to the Dai fishery, on fish from different genera and trait groups. The gillnet selected for fish that migrate laterally from the floodplain to the main river and for higher trophic level fish. Gillnets may target groups of fish that are less impacted by the long-standing Dai fishery. For both fisheries, we note a need for monitoring fish lengths in order to understand the effects of selection on population dynamics and species-specific trait changes.

Dynamics of bacterial community in Tonle Sap Lake, a large tropical flood-pulse system in Southeast Asia

2019 ◽  
Vol 664 ◽  
pp. 414-423 ◽  
Author(s):  
Porsry Ung ◽  
Chanthol Peng ◽  
Sokunsreiroat Yuk ◽  
Reasmey Tan ◽  
Vannak Ann ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Southeast Asia ◽  
Flood Pulse ◽  
Pulse System ◽  
Tonle Sap Lake ◽  
Tonle Sap

Multidecadal variability of the Tonle Sap Lake flood pulse regime

2021 ◽  
Author(s):  
Aifang Chen ◽  
Junguo Liu ◽  
Matti Kummu ◽  
Olli Varis ◽  
Qiuhong Tang ◽  
...  
Keyword(s):  
Flood Pulse ◽  
Pulse Regime ◽  
Multidecadal Variability ◽  
Tonle Sap Lake ◽  
Tonle Sap

scholarly journals Mollusc fisheries and length–weight relationship in Tonle Sap flood pulse system, Cambodia

2018 ◽  
Vol 54 ◽  
pp. 34 ◽  
Author(s):  
Peng Bun Ngor ◽  
Ratha Sor ◽  
Leang Hour Prak ◽  
Nam So ◽  
Zeb S. Hogan ◽  
...  
Keyword(s):  
Annual Variation ◽  
Flood Pulse ◽  
Growth Patterns ◽  
Water Levels ◽  
Relationship Analysis ◽  
Weight Relationship ◽  
Daily Data ◽  
Tonle Sap ◽  
Mollusc Species ◽  
One Year

Molluscs are important for ecological function, livelihoods and fisheries, but are often forgotten in research and management. Here, we investigated intra-annual variation in the landing and growth patterns of three mollusc species, i.e., Corbicula moreletiana, Pila virescens and Pila ampullacea, using one-year daily data on landing catches and values, recorded in Kampong Chhnang province of Tonle Sap (TS) Lake. Overall, 8330 tonnes with a first sale landing value of US$ 1.4 million for the three species were reported. Also, we found that C. moreletiana was abundant during the dry season with high temperature and less precipitation. By contrast, the two Pila species were abundant from the early rainy to early dry seasons when precipitation and water levels increase. The length–weight relationship analysis indicated that a faster growth in weight of Pila species occurred in the rainy season, and a general negative allometric growth was observed for the three species. This implies that their populations were intensively fished. Our preliminary results suggest that molluscs in the TS Lake (i) are important resources in support of people's livelihoods, (ii) respond differently to intra-annual variation in temperature, precipitation and hydrology and (iii) are being intensively exploited with significant reduction in growth rate. Therefore, it is necessary to conduct further comprehensive research describing status of mollusc stocks and their ecology to support long-term management and conservation of this important aquatic fauna. Our study contributes to establishing the first important baseline data and information on key mollusc species for the TS.

scholarly journals Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia

2014 ◽  
Vol 11 (2) ◽  
pp. 2177-2209 ◽  
Author(s):  
M. E. Arias ◽  
T. Piman ◽  
H. Lauri ◽  
T. A. Cochrane ◽  
M. Kummu
Keyword(s):  
Environmental Flows ◽  
Numerical Models ◽  
Flood Pulse ◽  
Economic Incentives ◽  
Water Levels ◽  
Surface Hydrology ◽  
Development Scenarios ◽  
Tonle Sap ◽  
Hydropower Potential ◽  
Annual Water

Abstract. River tributaries have a key role in the biophysical functioning of the Mekong Basin. Of particular attention are the Sesan, Srepok, and Sekong (3S) rivers, which contribute nearly a quarter of the total Mekong discharge. Forty two dams are proposed in the 3S, and once completed they will exceed the active storage of China's large dam cascade in the upper Mekong. Given their proximity to the lower Mekong floodplains, the 3S dams could alter the flood-pulse hydrology driving the productivity of downstream ecosystems. Therefore, the main objective of this study was to quantify how hydropower development in the 3S would alter the hydrology of the Tonle Sap floodplain, the largest wetland in the Mekong and home to one of the most productive inland fisheries in the world. We coupled results from four numerical models representing the basin's surface hydrology, water resources development, and floodplain hydrodynamics. The scale of alterations caused by hydropower in the 3S was compared with the basin's definite future development scenario (DF) driven by the upper Mekong dam cascade. The DF or the 3S development scenarios could independently increase Tonle Sap's 30 day minimum water levels by 30 ± 5 cm and decrease annual water level fall rates by 0.30 ± 0.05 cm d−1. When analyzed together (DF + 3S), these scenarios are likely to eliminate all baseline conditions (1986–2000) of extreme low water levels, a~particularly important component of Tonle Sap's environmental flows. Given the ongoing trends and large economic incentives in the hydropower business in the region, there is a high possibility that most of the 3S hydropower potential will actually be exploited and that dams would be built even in locations where there is a high risk of ecological disruptions. Hence, retrofitting current designs and operations to promote sustainable hydropower practices that optimize multiple river services – rather than just maximize hydropower generation – appear to be the most feasible alternative to mitigate hydropower-related disruptions in the Mekong.

scholarly journals Population dynamics of the migratory fish Prochilodus lineatus in a neotropical river: the relationships with river discharge, flood pulse, El Niño and fluvial megafan behaviour

2010 ◽  
Vol 8 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Marinke J. M. Stassen ◽  
Max W. P. M. van de Ven ◽  
Tjisse van der Heide ◽  
Marco Antonio Guerrero Hiza ◽  
Gerard van der Velde ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Flood Plain ◽  
Flood Pulse ◽  
Relative Importance ◽  
Migratory Fish ◽  
Prochilodus Lineatus ◽  
El Niño Event ◽  
Main River ◽  
Sedimentation Processes

The relative importance of flood pulse dynamics and megafan behaviour for the Sábalo (Prochilodus lineatus) catches in the neotropical Pilcomayo River is studied. The Sábalo catches can mainly be explained by decreased river discharges in the preceding years resulting in smaller inundated areas during rainy season floods and thereby in a decreased area of feeding grounds for the fishes. The decreased river discharges and the related decline of Sábalo catches in the 1990's can be linked to the 90-95 El Niño event. In 2007 the Sábalo catches were comparable to the catches before the "El Niño" event. The connectivity (continuity) between the main river and flood plain areas, which is influenced by sedimentation processes, is also of great importance and very probably plays a more important role since the late 1990's.

Planktonic diatom community dynamics in a tropical flood-pulse lake: the Tonle Sap (Cambodia)

2019 ◽  
Vol 34 (1) ◽  
pp. 1-22
Author(s):  
Loïc Tudesque ◽  
Thomas K. Pool ◽  
Mathieu Chevalier
Keyword(s):  
Community Dynamics ◽  
Flood Pulse ◽  
Diatom Community ◽  
Planktonic Diatom ◽  
Tonle Sap

scholarly journals Flood mapping under an extreme event in a large shallow lake influenced by flood pulse in Southeast Asia

2020 ◽  
Vol 148 ◽  
pp. 06004
Author(s):  
Sokly Siev ◽  
Vannak Ann ◽  
Takashi Nakamura ◽  
Hideto Fujii ◽  
Chihiro Yoshimura
Keyword(s):  
Southeast Asia ◽  
Water Level ◽  
Shallow Lake ◽  
Flood Risk ◽  
Extreme Event ◽  
Gumbel Distribution ◽  
Flood Pulse ◽  
Water Levels ◽  
Mekong River ◽  
Flood Mapping

Tonle Sap Lake (TSL) in Cambodia is the largest shallow lake in Southeast Asia. Influenced by flood pulse system of the Mekong River, TSL provides diverse benefits including ecosystem services, ecological functioning, and flood water storage in the floodplains. However, extreme events (e.g., flooding) due to rising water level caused by dam break and/or heavy rainfall in the Mekong River Basin could threaten the ecosystems of the lake, community health and economic growth in the region. Flood mapping under such extreme event could be informative in the flood risk and emergency management. In this study, we aim to develop a flood risk boundary map in TSL using an existing 2D hydrodynamic model (Caesar-Lisflood, CL) with rising water levels estimated by Gumbel distribution. As a result, the extreme water level of 1% chance (or 100-year flood return period) exceeding the annual maximum water level at Prek Kdam station was approximately 11.38 m resulting in the largest inundation area of 15193 km2. Overall, the employed method and flood risk mapping are useful for the decision makers to manage flood risks and emergency in the lake. This is to anticipate the consequences of a possible rising water level by an extreme event.

Modelling spatial and temporal dynamics of two small mud carp species in the Tonle Sap flood-pulse ecosystem

2019 ◽  
Vol 392 ◽  
pp. 82-91 ◽  
Author(s):  
Bunyeth Chan ◽  
Ratha Sor ◽  
Peng Bun Ngor ◽  
Christophe Baehr ◽  
Sovan Lek
Keyword(s):  
Temporal Dynamics ◽  
Flood Pulse ◽  
Tonle Sap ◽  
Spatial And Temporal Dynamics
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