Mumbai: Scores of dead fish greet visitors at Banganga water tank

Experts cite food offerings during ritual as reason, call for immediate action

A distressing sight greeted devotees and visitors as hundreds of dead fish floated to the surface of the historic Banganga water tank at Walkeshwar on Monday morning. This occurrence, though not unprecedented, has raised concerns over the environmental impact of an annual religious ritual that has been practised for generations.

Pitru Paksha, a time-honoured Hindu tradition, is a 16-day period during which families pay homage to their ancestors. As part of the ritual, devotees offer food to the departed souls. However, it is the subsequent act of submerging this food in the sacred Banganga tank that has been associated with the recurring deaths of fish in the area.

The Walkeshwar Temple, which dates back to the 12th century, holds immense cultural and religious significance for the people of Mumbai. The Banganga tank, a step well located within the temple complex, has been a central element of the Pitru Paksha ritual, wherein families offer rice, sweets and other food items to their ancestors. This act of devotion, while deeply rooted in tradition, has been under scrutiny due to its impact on the aquatic ecosystem.

The food offerings, once submerged in the Banganga tank, gradually decompose, releasing organic matter and pollutants into the water. Over the years, this contamination has proven detrimental to the tank's resident fish population. Water pollution, resulting from this age-old practice, has led to oxygen depletion in the water, which in turn, causes distress and mortality among the aquatic life.

In response to the ongoing environmental concerns, Pramod Mandrekar, a local resident and ex-corporator, shared his perspective. “The major cause of this is the immersion of rice balls, also called pindas, in the water body. The oil mixed with these rice balls rises to the water surface post-immersion. This cuts off the water body from fresh oxygen supply, which is one of the causes of the death of fish.” Mandrekar said. According to him, the situation can be avoided if the local authorities make a provision for artificial ponds like the ones used for Ganesh Visarjan.

What experts say

Pillu Avhad, a seasoned fishkeeping enthusiast with over 20 years of experience, shed light on the technical aspects contributing to the demise of the fish population. Avhad explained that the immersion of pindas on such a large scale in any water body leads to massive availability of a food source, disrupting the existing nitrogen cycle. “The massive food source, which decomposes, causes the formation of high levels of ammonia in the water body, referred to as an ammonia spike. This causes ammonia poisoning in fish, burning their skin and ultimately leading to their death. The existing nitrogen cycle is not capable of handling such high levels of ammonia, as the nitrifying bacteria are limited and take time to form,” Avhad said.

According to Avhad, even if the fish survive ammonia poisoning, they face the threat of nitrite poisoning. “The ammonia converts to nitrites. High levels of nitrite are toxic to fish because it binds with the haemoglobin in their blood to form methemoglobin, which reduces oxygenated blood flow to their organs and causes multiple organ failure leading to death,” Avhad said, adding that the large availability of a food source also leads to extensive overfeeding, which can also cause death. These insights highlight the urgent need for a comprehensive solution to protect the fish and maintain the ecological balance at Banganga.

Oct 14
Day period of Pitru Paksha ended

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