Every spring, more than 300 harbor seals are observed in Bigeum Island, located off South Korea's western coast; however, their population is gradually declining, prompting authorities to declare the species as endangered for the month of March. The Ministry of Environment noted that while indiscriminate capture for fur trading previously threatened the species, the current primary factors contributing to its dwindling numbers include accidental bycatch, coastal development, disturbance from ship movements, and habitat destruction.

In light of these pressures, the Ministry elevated the harbor seal's status from Endangered Wild Species II to Endangered Wild Species I in 2022. Under South Korean wildlife protection laws, capturing, harming, or collecting individuals of species categorized as Endangered Wild Species I without permission can result in severe penalties, including up to five years in prison or hefty fines ranging from 5 million to 50 million won. The harbor seal (Phoca largha) is notably the smallest species among seals, characterized by a gray to tawny body adorned with dark spots, giving it its alternate name, spotted seal.

The physical traits of the harbor seal allow it to effectively inhabit rocky islands, sandy spots, and ice floes for resting. Its diet consists of various fish, large crustaceans, squid, and octopus, with a breeding season occurring between January and March, during which it typically gives birth to one pup on an ice floe. Newborn pups are white to provide camouflage on the ice. Globally, harbor seals are primarily found in the northwestern Pacific, around the Kamchatka Peninsula in Russia, and in the Sea of Okhotsk. They typically stay in icy waters from winter to spring, migrating toward coasts from late summer to autumn, with Bigeum Island being a prominent location for the species, sheltering roughly 300 individuals as of 2024.