Diadromous fishes such as salmon and freshwater eels suddenly arrive in rivers from the sea at certain times of the year. They are interesting research subjects for scientists and have been valuable food resources for people since ancient times. Long-term fluctuations in salmon catch and eel production in Japan follow a similar pattern. This is because both are heavily influenced by human activities. In recent years, both salmon and eels have been decreasing in abundance and increasing in distribution value. Because these diadromous fish species migrate long distances over a lifetime among different aquatic environments such as oceans, estuaries, and freshwater rivers, even a single environmental disturbance can have an immediate impact on stocks. Therefore, in order to coexist with these fish in the long term, it is first essential for the general public to take an interest in them.

Therefore, we conceived and produced the “Web Dictionary of Salmon and Eels” to learn about the attractiveness of our familiar diadromous fishes and the global environmental conditions affecting them. This web dictionary was made as part of a project for basic marine education research at the Center for Marine Education, Graduate School of Education, the University of Tokyo. The web dictionary contains underwater photographs of swimming fishes, vivid illustrations by artist Yusei Nagashima, and a short animation that introduces the life histories of both salmon and eels. We believe that such web-based educational contents will be useful for educational fields in today’s information-oriented society.

Text: Mari Kuroki (Associate professor)