The J&K government has attributed the death of thousands of fish in the Dal Lake in Srinagar to “thermal stratification”. An in-depth study by the country’s top fisheries university, the Central Institute of Fisheries Education, Mumbai, in December, 2022 had forewarned of widespread pollution making the lake’s ecosystem unviable for fish production. A research paper titled ‘Assessment of Fisheries and Management: Insights from Dal Lake, Kashmir’ published by the Indian Journal of Extension Education has drawn a grim picture of the Dal Lake, a major attraction for tourists visiting Kashmir and one of the key water bodies for fish in Kashmir.
“Pollution has badly affected the Schizothorax fish harvest and has destroyed the breeding grounds of the native fish. This impact has been very severe since 2007-08 and had a tremendous effect on the total fish production in the Dal Lake,” the study pointed out.
Downward trend
Data on harvest of Schizothorax, a local fish species known as ‘Kashir gaad’ or ‘Snowtrouts’, from the lake between 1989 to 2019, shows a downward trend from around 240 tonnes in 1989-90 to less than 100 tonnes in 2018-19. Carp was introduced in Kashmir in 1957. The carp catch went up from 190 tonnes in 1989-90 to 350 tonnes in 2019. The total fish catch, however, shows no significant growth since the catch touched its highest at 475.65 tonnes in 2003-04. The annual catch from Dal lake, including all stocked and non-stocked fishes, was 450.5 tonnes. The total fish catch hit a low at 262.03 tonnes in 2007-08.
“The total fish harvest from the lake has not increased much over the last few decades. Lack of proper governance, policy regulations and coordination between government agencies and fishers adds more negative impact. As observed, most of the policies have been formulated without considering fishers’ perceptions,” the study pointed out.
The study suggested that the lake’s alkalinity has gone up from 69.5 milligrams per litre in 1974-76 to 101.75 in 2018. Alkalinity measures the ability of the water body to neutralize acids and bases to maintain a fairly stable pH level (acid-water ratio), essential for fish and other aquatic life. It said the lake’s pH value has gone up from 7.4-9.5 in 1974-76 to 7-10. A healthy lake’s pH value should be less than nine.
The chloride content of the water has drastically increased over the last two decades from 2 to 2.7 mg/l in 2007 to 10.3 mg/l in 2017, “which may be due to drainage from catchment areas, raw sewage coming from houseboats and nearby settlements and organic runoff from floating gardens”.
Climate change factor
The study also warned of the impact of climate change. “The water quality of the lake has deteriorated due to reduced inflow from streams, probably due to climate change in the Himalayan region. Besides, human settlements, hotels, floating gardens, and even washing points on the periphery have contributed to the lake’s slow death,” it added.
The study does not highlight any thermal stratification or increase in water temperature. “The water temperature in 1974-76 was 16.4 degree Celsius, 15 degrees Celsius in 2006-07 and 16.4 degree Celsius in 2018,” it noted. On May 26, large parts of the Dal lake were engulfed by the stench of thousands of dead fish floating ashore. “The size of the affected fish, known as the Gambusia species, is three to four inches. Our scientific wing has examined the issue. The fish died due to erratic weather causing thermal stratification — a change in the temperature at different depths in the lake,” Bashir Ahmed Bhat , Vice Chairman, J&K Lake Conservation & Management Authority (LCMA), had said.