TAIPEI (Taiwan News) — About 630 dead fish were found in Keelung’s Dawulun River Tuesday (Aug. 13), with low oxygen levels blamed for the deaths.

Keelung’s Bureau of Environmental Protection dispatched a team to remove the fish and test the water quality, per CNA. The team discovered dangerously low oxygen levels in the river.

Bureau Director Ma Chung-hao (馬仲豪) said crews expect to finish cleaning up the dead fish by Tuesday afternoon. Water samples revealed low dissolved oxygen levels of 0.76 mg/L in the river, compared to the normal range of 3 mg/L.

Officials will also probe for possible wastewater pollution. Those who violate water pollution control regulations by using pesticides or fertilizers, dumping waste, or discharging pollutants within designated areas face fines of NT$30,000 (US$926) to NT$300,000.