How a chance discovery in 1918 revealed Taiwan's rarest mountain-dwelling salmon species
In 1918, a graduate student exploring Taiwan’s high-altitude streams stumbled upon a unique red-spotted fish. This discovery, later identified as the Formosan Landlocked Salmon, linked the island’s freshwater ecosystem to distant Japanese counterparts. Today, this rare species remains a symbol of Taiwan’s fragile biodiversity and the history of its scientific exploration.
The story of the Formosan Landlocked Salmon began with Masamitsu Oshima, a graduate student tasked with mapping the freshwater fish populations of Taiwan, which was then a Japanese colony. While surveying the mountainous regions near Taichung, Oshima encountered a specimen collected by his colleague, Takeo Aoki. The fish displayed distinct red spots that immediately reminded Oshima of the trout species found in his native Japan, yet it possessed unique characteristics that suggested it was something entirely different.
Oshima consulted his doctoral advisor, Dr. David Starr Jordan, a prominent ichthyologist and the first Chancellor of Stanford University. Together, they analyzed the specimen and, in November 1919, formally announced the discovery of the Formosan Landlocked Salmon as a new species. This finding was significant not only for the field of ichthyology but also for understanding the biogeographical connections between the island of Taiwan and the broader Asian region, as the fish had become isolated in the high-altitude streams of the mountains.
The salmon is now recognized as one of the rarest fish in Taiwan, serving as a critical indicator of the health of the island's freshwater environments. Its existence highlights the importance of early 20th-century biological surveys in identifying species that might otherwise have remained unknown to science. The legacy of Oshima and Jordan’s work continues to influence how researchers approach the conservation of isolated populations, emphasizing the delicate balance required to maintain such rare species in their natural, high-elevation habitats against the pressures of a changing environment.
