Gray whales once migrated through Korean waters. Underwater recordings captured their songs until the 1970s. The acoustic library now documents an extinct migration route.
Rockcare, CC BY-SA 3.0, via Wikimedia Commons
An Ancient Connection
For thousands of years, the waters off Ulsan were a thoroughfare for migrating whales. This deep relationship is etched into the Bangudae Petroglyphs, a series of rock carvings dating as far back as 6,000 BCE. These detailed images show whaling scenes, with multiple boats and crews hunting several species of whales, is some of the world's oldest evidence of organized whaling. The specific animals carved on the rock faces are identifiable, evidence of the artists' deep familiarity with the local marine life.
The main species is the Western Gray Whale, Eschrichtius robustus. This population, now critically endangered, once migrated annually along the Korean Peninsula. They traveled from summer feeding grounds in the Sea of Okhotsk and off Sakhalin Island to winter calving lagoons presumed to be in the South China Sea. The coast of Ulsan was an important point on this route. Whaling records from the early 20th century show two peak seasons for gray whales in these waters: one from December to January during the southward journey, and another from March to April as they returned north.
A Migration Silenced
The traditional relationship between humans and whales in Ulsan changed dramatically with the arrival of industrial whaling. Russian whalers established operations in the port of Jangsaengpo in 1891, followed by Japanese companies after the Russo-Japanese War. Modern techniques and factory ships led to a rapid and devastating decline in the whale populations.
The Western Gray Whale population was hunted to the brink of extinction. By the 1930s, many considered them to be completely gone. Sightings became increasingly rare. The last confirmed sighting of a gray whale in Korean waters occurred on January 3, 1977, when two individuals were spotted off the coast of Ulsan.
Before they vanished, their sounds were captured. Cold War-era hydrophone arrays, likely intended for submarine detection, inadvertently recorded the vocalizations of the last gray whales to pass through the Ulsan Bight. This acoustic data, recorded into the 1970s, is a unique and somber archive. It is the only remaining evidence of the sounds of this specific migration path. Today, the Western Gray Whale population numbers fewer than 300 individuals, and the historic Korean migration route is considered functionally extinct.
💡Fun Facts
The Bangudae Petroglyphs contain 312 distinct images, including detailed scenes of whale hunts with boats carrying up to 18 people.
Gray whales are bottom-feeders, turning on their sides to scoop up sediment from the seafloor and filter out small crustaceans.
The gray whale migration is one of the longest of any mammal, with some individuals traveling up to 14,000 miles (22,500 km) round-trip.
Gray whales earned the nickname "devil fish" from 19th-century whalers because of their aggressive and protective reactions when hunted.
