Chungnam Institute of Fisheries Resources Releases 5,000 Fish to Restore Resources and Ecosystem

The Chungnam Institute of Fisheries Resources announced on the 29th that it has released 5,000 juvenile jong-eo (a large freshwater fish that disappeared from the Geumgang River), produced at its own facility, to restore their population and the local ecosystem.

This release marks the first in seven years since 2019. Held at the Gudeurae Ferry on the Geumgang River in Buyeo-eup, Buyeo-gun, the release event was attended by about 50 people, including local residents and related officials.

The juvenile jong-eo were produced through artificial seed trial research in July 2025, and are medium-sized fish that have grown to an average of 15–20 cm after being raised for one year and two months.

It is known that jong-eo take 5 to 7 years to grow into adults and spawn, and because the sexual maturity conditions required to use them as broodstock are not clearly understood, it is extremely difficult to produce artificial seeds stably.

Despite these difficulties, the Institute moved away from traditional sexual maturity induction methods for producing juvenile jong-eo. To ensure stable resource recovery and continuous releases, the Institute has pursued various trial researches every year, successfully producing artificial seeds this year following its success in 2025.

Jong-eo have been evaluated as a precious fish species representative of the Geumgang River, recognized as a delicacy presented to successive kings since the Joseon Dynasty, with the jong-eo from the Geumgang River considered to have the best taste.

However, due to environmental destruction from the development of river estuaries—their main habitats—as well as water pollution and overfishing, they have rarely been caught domestically since the 1980s, and have been considered virtually extinct in the country.

Accordingly, the Inland Fisheries Research Institute initiated the first release in 2007 to restore jong-eo resources, and the provincial Institute has been pursuing the "Jong-eo Restoration Project" in cooperation with the central research institute since 2017.

From the first release in 2007 until 2019, a total of 11,200 jong-eo were released into the Geumgang River around Buyeo-gun and Seocheon-gun, where they historically inhabited. In 2020, juvenile fish naturally reproduced from the released jong-eo were caught, confirming the possibility of partially restoring the jong-eo population within the Geumgang River.

Cho Min-seong, head of the Chungnam Institute of Fisheries Resources, said, "Jong-eo are precious fish known for their exceptional taste, as their name suggests. We will strive to restore the former reputation of jong-eo in the Geumgang River through continuous research and releases." He added, "We will also do our best to continue artificial seed production and ecological and reproductive research on jong-eo, leading not only to the restoration of the Geumgang River ecosystem but also to increased income for fishermen."