Eulsukdo was created by combining Ilwuldo and Eulsukdo, which were the upper and lower halves of the island that was separated by the construction of the Nakdonggang estuary bank. On July 13th, 1996, Eulsukdo was designated as Natural Monument #179 (Bird Sanctuary of the Nakdonggang Estuary). Originally, the island was at high risk of being submerged due to its low elevation. The establishment of Yunjungje (underwater barrier) and active reclamation work encouraged many residents to move to the island. The island even became a horticulture supply center for Busan. With the completion of the Nakdonggang estuary bank in April 1987, however, the whole island transformed into a public park. The increase in the number of visitors resulted in damaged reed fields and intensified ecosystem degradation. In response, Busan nullified the development plan for Eulsukdo and instead designated it as a core preservation area. Effective restoration work over the next six years (1999 – 2005) successfully resulted in creating an ecological park.