Hundreds of dead fish were found floating on Sunday in Dighalipukhuri water tank in Guwahati. An examination of the collected samples of the dead fish and the waterbody revealed that depletion of dissolved oxygen in the tank coupled with high organic load led to the incident.
Following the detection of around 600 kilograms of 400 dead fish of different species in the tank, Assam Fisheries Minister Parimal Suklabaidya had directed the officials of the department to visit the site and ascertain the cause behind the mass deaths.
"Fish mortality was due to sudden dip in oxygen level and high organic load in the tank. Departmental officers after examination found deaths of fish not due to poisoning but environmental degradation," said Mr Suklabaidya.
The department, as a short-term measure, increased the oxygen level in water by showering water through pump and creating wave action through mechanised boats.
The Dighalipukhuri or long pond in Assamese - more than 500 metres long - is located in the Ambari area in the heart of Guwahati.