Dokdo Sea Lions (Gangchi) Extinction: Forgotten Wildlife of Korea

Dokdo and the Lost Sea Lions (Gangchi): Forgotten Wildlife of Korea

The islets of Dokdo, located in the East Sea (Sea of Japan), are known today as a symbol of sovereignty and national pride for Korea. However, beyond politics and territorial debates, Dokdo was once home to a unique marine mammal: the Korean sea lion, known locally as Gangchi (강치). These animals thrived in the waters surrounding Dokdo for centuries before their tragic extinction in the 20th century. This article explores the forgotten history of the Dokdo sea lions, their ecological role, and what their loss teaches us about conservation.

The Sea Lions of Dokdo: Korea’s Forgotten Marine Mammals

The Korean sea lion (Zalophus japonicus), closely related to the California sea lion, was once abundant in the East Sea. Historical records describe groups of sea lions basking on the rocky shores of Dokdo, Ulleungdo, and nearby islands.

• Local Name: Gangchi (강치), widely used by residents of Ulleungdo.
• Physical Traits: Similar in size to the California sea lion, with males reaching up to 2.3 meters in length.
• Behavior: Known for gathering in colonies, feeding on fish and squid, and serving as a key predator in the marine ecosystem.

Why Did the Dokdo Sea Lions Go Extinct?

Despite their ecological importance, the Korean sea lions faced multiple pressures that led to their extinction by the mid-20th century.

Major Causes of Extinction

Cause	Description
Overhunting	Japanese commercial hunters killed tens of thousands of sea lions for fur, oil, and meat during the early 1900s.
Habitat Loss	Frequent human activity and military use of Dokdo reduced resting and breeding spaces for sea lions.
Decline in Food Sources	Overfishing in the East Sea diminished fish stocks, reducing the sea lions’ natural prey.
Colonial Exploitation	During the Japanese colonial period, resource extraction was prioritized over ecological balance.

Last Sightings of the Korean Sea Lion

The last confirmed sightings of Korean sea lions occurred in the 1940s near Dokdo and Ulleungdo. By the 1950s, they were considered functionally extinct. Occasional unverified reports surfaced in later decades, but no scientific evidence confirmed their survival. In 1996, the International Union for Conservation of Nature (IUCN) officially declared the species extinct.

Ecological and Cultural Legacy

The loss of the Korean sea lion was not only an ecological tragedy but also a cultural one. Gangchi held a place in local traditions and diets, and its disappearance severed a long-standing human-wildlife connection.

Pros of Remembering the Lost Sea Lions

• Raises awareness about the consequences of overexploitation.
• Strengthens the argument for marine conservation in Korea.
• Provides a cultural and ecological symbol for environmental education.

Cons and Challenges

• The extinction is irreversible; reintroduction is impossible.
• Limited public awareness means few people know about Gangchi.
• Conservation efforts often prioritize living endangered species, not extinct ones.

Lessons for Modern Conservation

The story of the Dokdo sea lions reminds us that wildlife loss is often silent and gradual until it is too late. Korea now emphasizes conservation of other endangered marine species, such as the finless porpoise and the spotted seal. Protecting these animals ensures that the tragedy of the Gangchi does not repeat itself.

Conclusion

The extinction of the Dokdo sea lions, or Gangchi, is a forgotten chapter in Korean natural history. While they no longer exist, their memory serves as a powerful reminder of the fragile balance between humans and nature. By learning from this loss, Korea and the world can strengthen commitments to protecting endangered species and safeguarding biodiversity for future generations.

References

• Kim, Jong-hak. Ecology of the Korean Sea Lion. Seoul: Nature Publishing, 1998.
• IUCN Red List. "Zalophus japonicus (Japanese sea lion)." https://www.iucnredlist.org
• Lee, Min-ho. "The Forgotten Sea Lions of Dokdo." Korean Journal of Marine History, vol. 12, no. 2, 2005.
• National Institute of Biological Resources (NIBR). Extinct Animals of Korea. Incheon, 2012.
• Stone, Roger. Lost Mammals of the Pacific Rim. Cambridge Wildlife Studies, 2006.

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