Scores of dead fished surfaced in drought-hit Australia’s Darling River on Monday, triggering panic, reports said. New South Wales Water Minister Niall Blair described it as an “environmental catastrophe unfolding”. This is the third incident of mass fish deaths in the river in the last two months.

Officials suspect the weather conditions, low water and oxygen levels and possibly toxic algae are factors that led to the deaths, The Sydney Morning Herald reported.

Investigators from the New South Wales Department of Primary Industries visited the site near Menindee town and said that more fish will die as the temperature is expected to rise and no rain has been forecast, AFP reported.

Blair said the government was running out of options to address the matter. “It’s not a case of not being able to spend money on something, there just isn’t any other alternative that anyone has offered up,” Blair said. “The only thing that will really change these conditions at the moment is fresh water coming through the system and there is just no possibility of that at the moment.”

Menindee Regional Tourist Association president Rob Gregory, who operates river cruises, put the onus on the authorities, ABC reported. Gregory claimed the government had allowed farmers to use too much river water to irrigate their fields.

Meanwhile, the Opposition’s shadow Environment Minister Tony Burke demanded a scientific explanation for the deaths.