The South Korean government attributed a mass die-off of carp in the upstream area of Soyangho lake to low dissolved-oxygen levels and bacterial infection [1].

The findings follow a period of ecological distress that has impacted local fishing communities and sparked a political dispute over environmental accountability. The event highlights the vulnerability of freshwater ecosystems to rapid temperature changes and runoff pollution.

The deaths began in April 2024 [1]. Government investigators announced their results in May 2024, saying that a combination of high spring temperatures and low rainfall reduced oxygen levels in the lower layers of the lake [1]. This environment, combined with bacterial infections, led to the mass mortality of the fish [1].

However, the cause of the die-off remains a point of contention. Some stakeholders have attributed the deaths to livestock waste and pesticide-contaminated runoff [3]. President Lee Jae-myung and Minister Kim Sung-wan of the Climate Energy Ministry previously raised concerns about the impact of pig and cow manure, as well as agricultural pesticides, entering the water [1].

These comments triggered a backlash from the livestock industry. Representatives from the sector called for Minister Kim's resignation, saying that the official linked the carp deaths to livestock farming without sufficient evidence [3].

Local fishermen have described a recurring cycle of loss. One fisherman said that after collecting dead carp one day, more carcasses appeared the next [2]. Despite the government's investigation, officials said that responsibility for the event remains unclear, and aid for affected fishermen has remained limited [1].

“The government attributed a mass die-off of carp in the upstream area of Soyangho lake to low dissolved-oxygen levels and bacterial infection.”

The discrepancy between the government's scientific conclusion and the concerns regarding agricultural runoff suggests a gap in how South Korea monitors non-point source pollution. While the immediate biological cause was oxygen deprivation, the underlying trigger—whether climatic or man-made—remains disputed, complicating the process of providing financial reparations to local fishermen.