Chalermchai Ratnarak, Egat deputy governor, said all eight sluice gates could be fully raised to increase the fish population in the Mekong river. Fish from the Mekong usually swim to spawn in Moon river and other tributaries from May to September. Since the dam was built in 1993, the number of fish species has declined from more than 250 to 90. Mr Chalermchai said the dam gates would stay open until cabinet decided on the dam’s fate. Cabinet opened them in mid-June last year.

However, he said Egat had lost 500-million-baht worth of electricity that the dam in Ubon Ratchathani was unable to produce in the past year. Deputy Prime Minister Gen Chavalit Yongchaiyudh, who oversees a working team on the Pak Moon dam conflict, said cabinet would delay a decision on the dam until an Ubon Ratchathani university study on the impact of the dam was finished. Both the cabinet-sponsored study and one sponsored by Egat, though incomplete, have found that the dam obstructs fish migration and has a negative impact on the environment.

Meanwhile, 500 dam protesters in Ubon Ratchathani have started to mobilise public support for a campaign to demand that the dam be decommissioned. Dam Chatapan, 58, said the gates should be opened permanently since the dam has no impact on electricity supply in the region. Decommissioning the dam would restore river ecology and bring back fish and plants, he said.