dead fish in the Tamsui River
Dead fish in the Tamsui River
Hundreds of thousands of mullet were reported dead in rivers across New Taipei City Monday, with a preliminary investigation indicating the cause of death was consecutive days of high temperatures rather than water pollution, the city's Water Resources Department said Tuesday.

The dead fish were found in the Tamsui River, Xindian River, Dahan River and Keelung River, officials said, adding that about 100,000 dead fish have so far been removed from the rivers.

The officials said they expected to finish removing the dead fish within three days.

According to the department, an initial investigation conducted by the city's Environmental Protection Bureau excluded the possibility of contamination, and instead pinpointed a lack of oxygen in the water due to recent hot weather, adding that the investigation is ongoing.

The amount of dissolved oxygen in the water near the dead fish was recorded at 0.6 milligrams per liter, much lower than the 2mg-4mg/l considered necessary for fish to survive.

The department said it has set up netting and floating blocks near local wharfs to prevent the dead fish being swept downstream and is working with the High Floodplain Project Management Office and fishermen to remove the fish.