A mass fish die-off in a reservoir in southern Vietnam’s Dong Nai province has shone a new light on soaring temperatures in Southeast Asia.

Fishermen have been working to wade through. Also to collect the hundreds of thousands of dead fish that have blanketed the 300-hectare Song May reservoir amid a ferocious heatwave.

Intense drought swept through Vietnam’s south in April. Temperatures rising to nearly 40 degrees Celsius (104 degrees Fahrenheit), leaving farmers struggling to keep their crops alive.

Community members and local media blame the drought, heatwave and reservoir management problems as contributing factors.

According to AFP, the lake’s water level was reportedly too low for the animals to survive, as there had been no rainfall for weeks.

Nghia, a resident from the province’s Trang Bom district, told AFP that the fish “died for lack of water,”. Also adding: “Our life has been turned upside down over the past 10 days because of the smell.”

Even with numerous buckets and nets, removing all the fish is almost impossible.

Local media has suggested that as many as 200 tons’ worth perished after a failed attempt to renovate the reservoir, according to AFP.

Nghia said the reservoir provides water for crops in the Trang Bom and Vinh Cuu districts. Its management had previously discharged water from it in an attempt to save crops downstream.

Tuoi Tre newspaper reported that extra water was initially planned to be released into the reservoir. It is done for the fish that were diverted downstream because of the “unrelenting heatwave,” according to AFP.

AFP said that authorities are investigating the mass die-off as efforts continue to remove the dead fish.