Mass die-off of fish suspected to be gizzard shad or baribaendaengi in Ulsan’s Taehwa River

【Financial News, Ulsan = Reporter Choi Soo-sang】 Hundreds of fish suspected to be gizzard shad or baribaendaengi were found dead in the lower reaches of the Taehwa River in Ulsan. They are believed to have died as water temperatures fell amid a sudden cold snap.
The Ulsan Environmental Movement Federation said on the 29th that the dead gizzard shad were found in the lower reaches of the Taehwa River, between Taehwa, Beonyeong and Hakseong bridges, mainly among the reeds and stone embankments around the bridge piers.
The Ulsan Environmental Movement Federation said an on-site inspection confirmed that the fish were wild gizzard shad measuring 10–15 cm in body length, and that hundreds had died.
The lower reaches of the Taehwa River are a brackish-water area where freshwater and seawater mix, providing habitat for a variety of fish, including gizzard shad, black porgy, eels and crucian carp.

Below Hakseong Bridge, where fishing is permitted, anglers line up to fish for gizzard shad every year from summer onward.
The exact cause of death has yet to be determined, but nearby residents suspect a lack of oxygen in the water or a drop in water temperature. Gizzard shad sometimes freeze to death in the Taehwa River in the middle of winter. Although it is autumn this time, the fish appear to have died after a sudden drop in air temperature also lowered the water temperature.
Some have also argued that the fish were not gizzard shad but the subtropical species baribaendaengi, citing the fact that they died in the low water temperatures of autumn. Baribaendaengi are found widely across subtropical and tropical waters, and have recently also been spotted off Busan and Ulsan as water temperatures have risen.
The sea temperature near Ulsan Port, in the lower reaches of the Taehwa River, was 24.4°C in early October, but on the 28th it measured 20.7°C, a drop of around 4 degrees.
The Environmental Movement Federation said the Jung-gu and Nam-gu district offices, which currently manage the area, are collecting the fish and will examine the carcasses to determine the exact cause of death.
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