Through the survey of this area in Juche 108 (2019), scientists of the Zoology Research Institute under the State Academy of Sciences proved that numbers of spotted seals and northern fur seals are living in the area and spotted seals are many more in number.

A spotted seal is 150-200cm in length and 50-100kg in weight, 120kg to the maximum. A young spotted seal is 90cm in length and 11kg in weight.

A bull northern fur seal is 135-200cm in length and a cow one is 110-135cm in length. A bull is 100-175kg in weight with 187kg to the maximum and a cow is 25-40kg in weight with 61kg to the maximum.

Spotted seals and northern fur seals appear in crowds in the area from early autumn to next year's spring.

The area of Uam-dong becomes a habitat of marine animals for its rich fish resources and good marine ecological environment.

The field of their activity ranges from the mouth of the Tuman River to the Bay of Sonbong with waters off Uam as a main area.