Heavy rainfall leads to mass die-off of clams at Dadaepo Beach due to Nakdong River estuary opening

Clams, known for their delicious taste, were found dead along the shoreline at a beach in Busan. What happened?

According to a report by 'SBS 8 News' on the 23rd, dead clams covered the sandy beach along Dadaepo Beach in Busan on the morning of the previous day (22nd).

Citizens who ventured barefoot along the beach had to carefully navigate through the clams, which were either left with only their shells or piled up in layers with their mouths open.

The dead clams found on that day are presumed to be the well-known brown-colored improved clams, also referred to as 'Galmi clams'.

Galmi clams, vulnerable to changes in salinity, face ecosystem tragedies every monsoon season

According to the National Fisheries Research and Development Institute and the Southeastern Marine Research Institute, Galmi clams that inhabit the brackish waters of the Nakdong River estuary are known to suffer mass die-offs every rainy season due to their sensitivity to changes in salinity.

With recent heavy rainfall raising the water level of the Nakdong River, the sluice gates were opened, leading to a significant inflow of freshwater and a rapid decrease in seawater salinity, which is cited as a major cause of this mass die-off.

A mollusk expert has estimated that the current situation is due to physiological imbalances stemming from a temporary low salinity phenomenon.

In an interview with the media, the expert explained, "Galmi clams are a species sensitive to changes in salinity, and if there is continued sudden influx of freshwater, the ion concentration and respiratory balance within their bodies can be disrupted, leading to death." They added, "Under normal conditions, freshwater and seawater mix naturally, maintaining salinity, but when the sluice gates are suddenly opened after being closed, the change in salinity can be drastic, significantly affecting the clams."

With the 'Busan Sea Festival' scheduled to start on the 1st of next month, concerns about coastal scenery and hygiene issues are growing. However, as of now, no clear measures to prevent recurrence have been established.

Image sources: knn news, reference photo for article understanding / pixbay