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Rivers, Salmon, Wetlands: Perspectives on Environmental Change in Kushiro, Hokkaido

Updated: Aug 24, 2023

Human Ecology: Rivers (HER) is a summer practicum course offered jointly by Sophia University’s Faculty of Liberal Arts and Graduate Program in Global Studies. The course began in 2014, and it concluded this year with a final five-day trip into Kushiro, Hokkaido.

The course explores the complex and intertwining relationships between humans and nature. As the name suggests, HER specifically focuses on rivers and how these living bodies of water interact with human society and the natural world in different ways.

These complex interactions are enshrined in Kushiro City. Nestled along the coast of southeastern Hokkaido, Kushiro seems quaint. For many tourists, the city is a rest stop; a gateway to an excursion into the lush nature reserves up north. Those who visit Kushiro recognize it for its preservation of nature, lending to an impressive geographical display of mountains, lakes, rivers and the largest wetland in Japan—Kushiro Shitsugen National Park.

Yet, even these contemporary natural landscapes are the culmination of centuries of transformation: not only from trading posts by the Matsumae clan and the forces of rapid industrialization in the Meiji era, but also from the long-existing Ainu communities along the river, from when the area was once called Kusuri.

Evidence of Kushiro’s industrial transformation emerge in Yonemachi Park (Yonemachi Koen, 米町公園), a small park overlooking the Fisher’s Wharf in the city’s coast. An unassuming observatory, the observation deck is demarcated by only a stout three-story lighthouse which extends into the sky, where visitors can freely view the coast of Kushiro through binoculars.

During the clear September day, we could see the faraway Mt. Mashu and Hidaka mountain ranges. The deciduous trees blanketing the mountains are juxtaposed with the Oji Paper Mill and Nippon Paper Mills that cluster around the much-closer Kushiro port, blending with the lines of fishing vessels which surround the central pier.

Sitting in Minami-Odori 8-Chōme, Yonemachi Park stands in the same location of the Kusuri trading post’s management headquarters during the Edo period. Across eons, the view from the observatory conjures the likeness of an old painting immortalizing the old Kushiro shore by painter and shogunate official Mekata Tatewaki, who surveyed the coasts of the area from 1853-1855.

Fig. 1. Mekata Tatewaki. (1871). 釧路州 釧路川 其3 (Kushiroshuu Kushirogawa Sono-3) [Painting on paper, enclosed in box]. Hokkaido University Library, Hokkaido, Japan.

Were it not for the mountainscapes, this view would be difficult to distinguish: the organic shoreline of the tiny peninsula have mostly been replaced with the geometric outlines of piers and wharves, where fishing vessels dock.

We took these images with us—convergences of the past and the present in Kushiro—as we continued our exploration of environmental change through Kushiro’s rivers, salmon, and wetlands.

Kushiro’s Rivers

Map of Kuhiro’s rivers, edited from Google Maps and OpenMaps

Driving eastward from Kushiro, the cerulean waters of the Pacific Ocean surround the coast of Hokkaido. In Akkeshi and Shibetsu, the wetlands give way to rising altitudes and gradual slopes. Here, Hokkaido’s iconic cow pastures appear in increasing quantities. An idyllic reminder of the dairy industry, these only appeared during the 1868 Meiji Restoration, where Hokkaido came under decrees of Japanese officials and Euro-American influence. Its proximity to the rivers and wetland promised fertile soils and ample supply for irrigation.

Caption: The soft serve ice cream shop and cafe in Akesato Ito Dairy Farm, Nemuro

Jutting out into the Pacific Ocean is Cape Kiritappu, at the far southeastern tip of Akkeshi. By traversing north and following the roads which circle Kushiro into the wetlands northward, we see the expanse of Kushiro Shitsugen National Park and the deep blue caldera lakes of Lake Kussharo and Lake Mashu. Mountain ranges veil the outlines of its clear, brilliant waters. On both sides of the road, perfectly-lined coniferous trees stand tall for many hectares, for use by lumber industries.

Two parallel rivers that travel southward from the larger Lake Kussharo: the naturally-formed meandering Kushiro River (Kushirogawa, 釧路川) and the engineered New Kushiro River (Shinkushirogawa, 新釧路川), which efficiently rallies water away from busy industries in Kushiro City. Kushiro River extends from Lake Kussharo, from where the river is born.

As the river cuts through the wetlands of Tsurui and Shibecha to the south, we encounter the Ashibetsu Hatchery (Ashibetsu Fukajou, 芦別ふ化場), a salmon hatchery that combines natural and artificial methods to supply the Japanese salmon market. The two rivers meet again in the Pacific Ocean, near Yonemachi Park.

South of Lake Kussharo also lies Teshikaga, where Iou Volcano (Iou-zan, 硫黄山; Ainu: Atosanupuri) straddles its border. Fumaroles emanate eternally from sulfur deposits at its foot. A charred cutaway is burned into one side of Mt. Iou, a result of volcanic gasses’ effects on surrounding vegetation. The terraformed depression on Mt. Iou’s facade is a remnant of a sulfur mine which once powered infrastructural development, military expansion and the extended railway system beyond during the Edo and Meiji period.

These tell only part of what affects salmon life cycles through the seemingly distant but interconnected transformations which meet at the Kushiro river.


We were fortunate to be given a step-by-step tour into how salmon are harvested in the Kushiro salmon hatchery, one of ten branches throughout Hokkaido. The manager explained to us that this branch is unique because they utilize both natural and artificial methods. This was not always the case. The HER class of 2015 visited the same site and witnessed the use of now-defunct urai machines along the Kushiro River.

This year, the theme of the course was on rewilding salmon in Eastern Hokkaido so this visit was of particular importance. Studying salmon brings us to their natural habitat: lakes, rivers and oceans. What these living bodies of water pass through gives glimpses of the interaction of human and natural forces which shaped rivers, salmon populations and histories. We are now seeing a sharp decline of wild salmon as a combination of different factors present threats and dangers to their survival. These threats include hatcheries, industrial development, river engineering, climate change, and diseases, to name just a few.

A major reduction in production after years of solely mechanical harvesting prompted the Kushiro salmon hatchery to include natural methods in 2019. This is significant for several reasons. First, the salmon are able to complete their life cycle. This results in benefits to biodiversity and ecosystem health throughout their journeys along the Bering Strait all the way to the Kushiro wetlands. Only salmon that have spawned and reached the end of their life cycles are harvested. Second, it presents the business case for using natural methods in salmon harvesting. Artificial means may provide large returns on investment in the short-term, but are ultimately unsustainable in the long-term. In addition, it is cost-effective because operational costs involving machines and manpower are avoided. Third, it is a novel approach that gives hope for the restoration of the natural environment. At the moment, this mixed natural-mechanical approach is not done elsewhere. The class is hopeful that it will be picked up as a normative practice, enabling benefits not only to the hatchery operators, but to the broader development of nature-society relations and values.

While it is unlikely in the near-future for a total shift to a natural approach, this case nonetheless gives great insight into how food production systems can transition away from over-reliance on artificial designs. It also highlights its necessity, and the need for collaboration and adaptive management in the face of a rapidly changing socio-ecological system. Indeed, this shift was the outcome of dialogue among staff and management, as well as a response to recommendations provided by researchers. Some of these views are reflected in the blogs of previous HER classes, and in the course’s two instructors in a 2020 journal article in Wetland Research.


On our fourth day, we trekked through Kushiro Shitsugen National Park (or Kushiro Wetland). The Kushiro Wetland is the largest marshland in Japan, and it encompasses the Kushiro River and four municipalities, namely Kushiro City, Kushiro Town, Shibecha Town, and Tsurui Village.

The long history of this wetland is deeply intertwined with the history of the Kushiro River. In the 1900s, river engineering projects were conducted extensively to straighten out the meandering river channels of the Kushiro River and to facilitate the economic development of the region. However, channelizing the river had unintended consequences. Following the 1960s, sediment began to flow more rapidly down the straightened river and accumulate in the wetland, causing the wetland to gradually dry up. Over the past six decades, the area of the Kushiro Wetland has decreased in size by approximately 20%-30%. Why is it concerning that the Kushiro Wetland is drying up?

Apart from improving water quality, controlling erosion, and maintaining the flow of water, the Kushiro Wetland provides a valuable habitat for thousands of plant and animal species. Among these is the tancho crane, or the Japanese red-crowned crown. The tancho crane, a now endangered bird that is found primarily in Eastern Hokkaido, is protected as a Special Natural Monument of Japan. Tancho cranes have long-held great cultural significance for people living in Kushiro, including the Ainu (the indigenous people of Hokkaido). In the Ainu language, the tancho crane is called the “Sarurun Kamuy,” which means “God of the marshes.”

The importance of tancho cranes to Kushiro identity became apparent the moment we stepped out of the plane into Tancho Kushiro Airport. Pictures and images of tancho cranes decorated the walls and welcome signs of the airport. During our five days in Kushiro, we learned how these birds give local communities a sense of place and meaning. The fact that tancho cranes are now endangered, largely as a result of the depleting Kushiro Wetland, not only threatens the local environment, but it also threatens the very cultural identity of Kushiro locals.


Our study visit to Hokkaido ended with a shared meal at the local fish market. From there, we could clearly see (and taste) a slice of the area’s political ecology: different kinds of freshly-caught fish species lined vendors’ shopfronts; the famed Hokkaido sweet corn, a product of industrial agriculture introduced only in the last century, was served in different meals; souvenir shops were filled with postcards and trinkets of the tancho crane and shima enaga. We were reminded of a passage in Aldo Leopold’s A Sand County Almanac, one of the first books we read for the course:

“When we hear his call we hear no mere bird. We hear the trumpet in the orchestra of evolution. He is the symbol of our untamable past, of that incredible sweep of millennia which underlies and conditions the daily affairs of birds and men.” [Leopold, p. 96]

Additional References

  1. Mekata Tatewaki. (1871). 釧路州 釧路川 其3 (Kushiroshuu Kushirogawa Sono-3) [Painting on paper, enclosed in box]. Hokkaido University Library, Hokkaido, Japan.

  2. Swanson, H. (2020). Landscapes, by comparison: Practices of enacting salmon in Hokkaido, Japan. In K. Ōmura, G. Otsuki, S. Satsuka, A. Morita (Eds.), The world multiple: The quotidian politics of knowing and generating entangled worlds (pp. 105-122). Routledge.

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