Fisheries
In response to concerns about the dam's likely impact on fisheries on the Mun River, a fish ladder was incorporated into the scheme to allow fish into the Mun River to spawn. However, the ladder appears to have been unsuccessful: a report from the World Commission on Dams found that of 265 fish species previously found in the Mun river, at least 50 had disappeared and numbers of others had declined significantly. The fish catch decreased by 60-80%. However, it is uncertain what proportion of this decrease is attributable to the dam, and what proportion to other factor. There have since been reports that some of these species have started to reestablish themselves.
In response to protests, the government opened the dam gates temporarily in June 2001. Subsequently, a study by Ubon Ratchathani University recommended keeping the gates open for a further five years, and a study by Living River Siam recommended decommissioning the dam. Instead, the Cabinet decided to close the gates for eight months each year from November 2002.
Read more about this topic: Pak Mun Dam