Gangneung, South Korea – A mass die-off of mullets at a fishing spot near Yeomjeon Beach in Gangneung has triggered a debate among anglers and environmentalists over the cause of the incident.

On the morning of March 8, approximately 100 dead mullets were discovered in the estuary area where fresh and salt water meet. Gangneung City officials collected around 50 of the carcasses and conducted water quality tests, finding that dissolved oxygen levels and pH were within normal ranges. Consequently, they decided not to pursue further testing.

The city's preliminary assessment, based on angler accounts, suggests that the deaths may have resulted from the release of mullets deemed too small or commercially unviable, or from injuries sustained during snag fishing.

However, anglers have presented various theories regarding the mass mortality. Some believe the fish may have succumbed to the stress of rapid environmental changes typical of springtime. Others have raised concerns about potential contamination from external pollutants, given the proximity of a thermal power plant and restaurants.

"I've been fishing in this area for about 30 years, and I've rarely seen so many dead fish at once," said one angler, suggesting that external factors, such as water pollution, likely contributed to the deaths.

Environmental groups have called for a more thorough investigation, emphasizing that on-site water quality measurements alone are insufficient to determine the cause. They point to the sensitivity of fish to water temperature fluctuations and the ongoing ecological changes in the area due to the construction of a thermal power plant.

"It's difficult to draw conclusions about the cause of this incident based solely on on-site water quality measurements," said Seo Jae-cheol, an expert at Green Korea United. "We need to investigate all possibilities, considering the rapid ecological changes in the area."

Gangneung City has announced plans to increase monitoring of the area and will consider further water quality testing if similar incidents occur.