Comment on “Designing river flows to improve food security futures in the Lower Mekong Basin”

Sabo et al. (Research Articles, 8 December 2017, p. 1270) used statistical relationships between flow and catch in a major Lower Mekong Basin fishery to propose a flow regime that they claim would increase catch, if implemented by proposed dams. However, their catch data were not adjusted for known variation in monitoring effort, invalidating their analysis.

The Mekong River supports fisheries that are important to more than a million people (1) and these fisheries are threatened by the rapid development of large dams for hydropower (2). Sabo et al. (3) used statistical relations between flow in the Mekong River and catch in an important fishery on the Tonle Sap River, Cambodia, to design a flow regime for the Mekong that could be generated by coordinated flow releases from future and existing dams (4). Sabo et al. projected that their proposed flow regime would increase yield from the fishery by a factor of 3.7, providing additional justification for large dams on the river. We separately objected to this study on different grounds (56) and later discovered that it used catch data that differ from the data reported by another study of the fishery using the same database (1) (Fig. 1). We diagnose the problem below, after describing the context.

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John G. Williams, Peter B. Moyle, Ashley S. Halls