Udaipur: Three endangered species of tortoises have died in the Kalyansagar lake of the famous Tripureswari temple here during the last fortnight, official sources said on Tuesday. The district magistrate of South Tripura district, Shantanu Das said one tortoise died on Monday and two others had died during the last fifteen days. "The department of fisheries was asked to investigate the cause of the deaths", the District Magistrate who is the official 'sebait' (servant of the goddess) of the temple said. Veterinarian, M K Dutta said the tortoises died due to bacterial infection from Salmonella. He said the water of the lake became acidic due to destruction of the ecosystem around the lake. Earlier, a team of experts studied the habitat of the tortoises in the lake and found that the cemented embankments spoilt the natural places for laying eggs. Seven tortoises died in the lake in the last six months.