Heavy monsoon and a delay in removing dead birds are the main factors which led to propagation of bacteria which killed over 18,500 birds in Sambhar Lake, the director of Bareilly-based Indian Veterinary Research Institute (IVRI) has said, warning that it may be repeated next year if the lake witnesses a similar rainfall and if the government fails to spot dead birds in time.
On Thursday, IVRI had confirmed avian botulism as the cause of the deaths of the birds in Sambhar. Talking to The Indian Express, IVRI director Dr Raj Kumar Singh said that the best way to prevent avian botulism from spreading is removing any dead birds at the earliest and incinerating them, rather than burying them in pits, like the Rajasthan government did.
Not spotting these dead birds in time was the most fatal error made by Rajasthan government and officials concerned. As per the IVRI report, birds recovered on November 10 were infested with maggots of third stage Calliphora species, “which clearly indicates that birds must have died 10-14 days prior to November 10.”
A heavy monsoon is another reason cited by IVRI for the deaths. “Heavy rains decreased the salt concentration to under 2 parts per million, thus creating a conducive environment for growth of zooplanktons, phytoplanktons and crustaceans, all of which harbour the said bacteria in their body,” Singh said.
But as the waters receded, the salinity “mildly” increased, “which must have led to the death of crustaceans, invertebrates and planktons,” as per the IVRI report. The bacteria then multiplied inside these dead crustaceans, invertebrates and planktons, leading to an accumulation of toxins,” he said.