The Formosan Landlocked Salmon: A Glacial Relict's Journey Home — From the Brink of Extinction to Taiwan's Watershed Conservation Miracle

30-second overview: The Formosan landlocked salmon (Oncorhynchus masou formosanus), a species unique to Taiwan, is a rare glacial relict. The Atayal call it "Mnbang." Once driven to the edge of extinction by human development — with only around 200 individuals documented in 1995 — more than two decades of effort by Shei-Pa National Park and conservationists, combining dam removal, artificial breeding, and the innovative "waterless transport of eyed eggs" technique, brought the wild population to a peak of 18,000 in 2023. Though slightly reduced by typhoons and earthquakes in recent years, numbers have remained stably above 15,000 — a successful model for watershed-integrated conservation in Taiwan, steadily returning this national treasure fish to its historical habitat.

In the autumn of 1917, a Japanese police officer in Yilan discovered a young Atayal man selling fresh salmon, which was an unimaginable sight in Taiwan at that time — salmon were cold-water migratory fish available only to the Japanese elite. This "salmon injustice" incident accidentally revealed the existence of a unique salmon in Taiwan's alpine streams, prompting the colonial government to dispatch ichthyologist Oshima Masamitsu for investigation¹.

Living Imprints of the Ice Age: The Origin and Discovery of the Formosan Landlocked Salmon

Oshima Masamitsu confirmed the existence of cold-water salmon in Taiwan's alpine streams and published his findings internationally. The Japanese named this precious fish "Saramao masu," derived from the Atayal place name "Saramao" (former name of the Lishan area) — the species now known as the Formosan landlocked salmon¹. It is a glacial relict unique to Taiwan: having arrived in Taiwan hundreds of thousands of years ago during the Ice Age, when tectonic shifts and warming climates ended its migratory cycle to the sea, it became landlocked, adapting to the freshwater environment of the upper Dajia River — making it the southernmost distribution of temperate salmon globally².

In Atayal culture, the Formosan landlocked salmon is called "Mnbang" (also spelled Bunban, Nbang, and other variants)³, and it was an important food source for the tribe. Artifacts unearthed from the Qijiaewan archaeological site demonstrate that the salmon had already been an important food source for indigenous peoples more than 2,000 years ago, intimately woven into traditional community life⁸.

📝 Curator's note: The Formosan landlocked salmon is a biological miracle and a living fossil of Taiwan's alpine culture — linking the memory of the Ice Age with the traditional wisdom of the Atayal people.

But as times changed, the fate of this national treasure fish came under severe threat from human activity.

Crisis at the Brink of Extinction: The Impact of Human Activity and Environmental Change

As development advanced, the Formosan landlocked salmon's habitat came under serious threat. In the 1960s, the opening of the Central Cross-Island Highway brought unprecedented development pressure to the upper Dajia River. High-altitude agriculture expanded rapidly, with orchards and vegetable farms pressing right to the stream banks; agricultural chemicals and fertilizers washed into streams with rainfall, severely polluting the water. In addition, check dams built for agricultural irrigation and hydropower changed the natural flow dynamics of the streams and blocked the salmon's migration routes, preventing movement between different river sections, causing inbreeding and genetic homogenization that dramatically reduced their viability. At one point, the short stretch of Qijiaewan Creek alone had more than ten check dams, severely fragmenting fish habitat¹. Invasive non-native fish species and early human fishing practices — including fish poisoning and electrofishing — further accelerated population decline.

By the 1980s, the Formosan landlocked salmon population had already plummeted to a few hundred individuals, surviving only in a stretch of approximately six or seven kilometers of Qijiaewan Creek¹. By 1995, field records showed the population had dropped to approximately 200-plus individuals — on the brink of extinction⁴. Research by Professor Lin Hsing-juh, Distinguished Lifetime Chair Professor in Life Sciences at National Chung Hsing University, found that typhoons and floods sweep fish downstream, but the presence of check dams prevents them from migrating back upstream, causing fish unable to tolerate higher water temperatures to die in large numbers — losing approximately one-third of the population each time⁴. During this period, conservationist Lin Yuan-lin lamented when facing the devastated streams: "Saramao masu, I am sorry."¹

📝 Curator's note: When a fish requires a human apology, it is both an ecological collapse and a condensed image of civilization's debt to nature.

Salvation at the Brink: Conservation Action and the Key Figure Liao Lin-yan

Faced with the dire situation of the Formosan landlocked salmon, Taiwan's conservationists embarked on a long and arduous restoration journey. Among them, Dr. Liao Lin-yan — Director of the Wuling Management Station at Shei-Pa National Park and known as the "Salmon Father" — invested more than twenty-five years in Formosan landlocked salmon restoration and stands as the key figure behind this success⁵. He worked in long-term collaboration with scholars such as Professor Lin Hsing-juh of National Chung Hsing University, jointly promoting a "watershed-integrated conservation" strategy that combines habitat improvement, artificial breeding, release management, and environmental education.

The conservation team adopted multiple strategies, including removing check dams to restore the stream's ecological corridor, allowing fish to migrate freely. In 2011, the removal of Qijiaewan Creek's No. 1 Check Dam was a major milestone — Taiwan's first ecological dam removal — after which the fish population in Qijiaewan Creek visibly recovered⁹. The team also constructed sewage treatment facilities to improve water quality, and promoted "farmland-to-forest" conversion policies: working with the Tzu Chi Foundation and corporate partners to acquire private land around Wuling Farm, planting hundreds of thousands of trees, effectively reducing water temperatures and decreasing pollution and sediment⁴.

On the artificial breeding front, in late 2003 the restoration team successfully used captive-bred Formosan landlocked salmon to collect sperm and eggs for the first time, hatching more than 10,000 young salmon — a major breakthrough achieving "complete aquaculture" that ensured the national treasure fish would not go extinct⁶. Liao Lin-yan then drew on experience gained during training in Hokkaido, Japan, to refine the "waterless transport of eyed eggs" technique. This technique allows eyed eggs to remain viable for up to 72 hours out of water. Though the actual survival rate is approximately 20%, its advantage is that it requires no large quantities of water — one person can carry a box (containing over 10,000 eggs, weighing approximately 15 kilograms), making it suitable for hiking into or accessing more remote streams at higher altitudes and lower water temperatures (such as Zhongyangjianjian Creek), effectively diversifying population risk to address rising water temperatures and drought caused by climate change⁴. In 2024, this technique was actually applied for releases at new sites including Zhongyangjianjian Creek; in 2025, the first helicopter release of Formosan landlocked salmon took place, using specially designed fish transport containers to further expand the restoration of historical habitat¹⁰.

Through these unrelenting efforts, the Formosan landlocked salmon population gradually recovered from approximately 200 individuals in 1995. According to Shei-Pa National Park statistics, the wild population reached a historical peak of 18,630 individuals in 2023⁴. Although it dipped slightly to 16,897 in 2024, the 2025 survey (published in January 2026) showed 16,020 individuals — maintaining a level above 15,000 for multiple consecutive years⁷. Despite some fluctuation from typhoons, earthquakes, and other natural disasters in recent years, conservation authorities emphasize this represents normal variation and that the overall restoration remains robust, with no significant decline.

📝 Curator's note: From 200 to 18,000 — behind the growth in numbers lies the arduous practice of Taiwan's society finding a new balance between economic development and ecological conservation.

Cultural Connection and Future Outlook: The Sustainable Path for the National Treasure Fish

The Formosan landlocked salmon is Taiwan's precious ecological asset, carrying rich cultural significance. In Atayal tradition, it is regarded as the gift of the streams, intimately connected to the tribe's life and beliefs. The 1917 "salmon injustice" incident was the catalyst for the salmon's discovery by the scientific community, reflecting the deep bond between indigenous peoples and their natural environment¹.

Despite the significant progress achieved in restoration efforts, the salmon's path to sustainability still faces challenges. The Formosan landlocked salmon is extremely sensitive to water temperature (the survival threshold is approximately 17°C or below), and extreme weather events caused by climate warming — droughts and heavy rainfall — may alter the hydrological conditions of streams and affect fish survival, representing the greatest long-term threat⁴¹¹. In addition, the continuity of habitat protection, the threat of invasive species, and potential human impacts on the environment are all key issues requiring sustained attention in future conservation work. Given the complex terrain, monitoring is difficult; current population surveys mainly rely on snorkeling visual surveys¹². Shei-Pa National Park Management Office states that the future goal is to enable the Formosan landlocked salmon to establish healthy satellite populations in more historical habitat sites and expand into streams at higher elevations to resist the impact of climate change. Beginning in 2026, Shei-Pa National Park will also deepen environmental education to help the public better understand this national treasure fish⁴.

The story of the Formosan landlocked salmon is a microcosm of ecological conservation in Taiwan — from endangered to recovering, witnessing the possibility of coexistence between humans and nature. Its journey home is the migration of a fish population and also Taiwan's shared pursuit of environmental ethics and sustainable development.

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