Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 4455
Title: Patterns of Ecosystem Metabolism in the Tonle Sap Lake, Cambodia with Links to Capture Fisheries
Author: Gordon W. Holtgrieve, Mauricio E. Arias, K. M. Irvine, D. Lamberts, E. J. Ward, M. Kummu, J. Koponen, J. Sarkkula, J. E. Richey
Publication Year: 2013
Journal: PLoS ONE
Volume: 8
Issue: 8
Pages: e71395
Keywords: ecosystem,fishing,metabolism

 The Tonle Sap Lake in Cambodia is a dynamic flood-pulse ecosystem that annually increases its surface area by over 600% with monsoon-driven rains. This flooding is thought to structure many of the critical ecological processes, including aquatic primary and secondary productivity. The lake also has a large fishery that supports the livelihoods of nearly 2 million people. Management of fisheries is hindered by a lack of scientific knowledge, in particular ecological data relevant to fish production. We used a state-space oxygen mass balance model and continuous dissolved oxygen measurements from four locations to provide the first estimates of gross primary productivity (GPP) and ecosystem respiration (ER) for the Tonle Sap. GPP averaged 4.1 ± 2.3 g O2 m-3 d-1 with minimal differences among sites. There was a negative correlation between monthly GPP and lake level (r=0.45) and positive correlation with turbidity (r=0.65). ER averaged 24.9 ± 20.0 g O2 m-3 d-1 but had >6-fold variation among sites and minimal seasonal change. Repeated hypoxia was observed at most sampling sites along with persistent net heterotrophy (GPP

Theme: Habitats to Support Sustainable Fisheries and Recovered Populations
Foci: Characterize habitat effects on ecosystem processes, ecological interactions and the health of organisms.