Translation guide
In Japanese, the concept of a non-native species is expressed through several terms that distinguish between introduced species, invasive species, and foreign species. The most common and neutral term is 外来種 (gairaishu), but context matters: scientific, legal, and everyday usage may call for different words.
The broad, neutral concept of a species introduced from outside its native range, without implying harm or benefit.
The standard term for any species introduced from another region. Used in science, policy, and everyday conversation. Neutral connotation.
There are non-native fish in this pond.
Literally 'introduced species'. Often used in ecological contexts to emphasize human-mediated introduction. Slightly more technical than 外来種.
We investigated the impact of introduced species on native species.
Similar to 外来種 but often used in legal or formal contexts (e.g., Invasive Alien Species Act). Can refer to any non-native organism.
Under the Invasive Alien Species Act, keeping designated invasive alien species is regulated.
A non-native species that causes ecological or economic harm, or threatens human health.
The direct equivalent of 'invasive alien species'. Used in scientific and policy contexts. Emphasizes the harmful impact.
Invasive alien species destroy native ecosystems.
Designated invasive alien species under Japanese law. Refers to species officially recognized as particularly harmful and subject to strict regulations.
Literally 'harmful non-native species'. Less common; used when emphasizing the negative effects without the legal designation.
Highlighting that a species comes from another country, often in everyday or commercial contexts.
Means 'foreign-produced' or 'of foreign origin'. Used for plants, animals, and products. Not necessarily invasive; just indicates non-native origin.
This flower is a non-native species.
Prefix meaning 'foreign' or 'imported'. Often used in compounds like 外来魚 (non-native fish) or 外来植物 (non-native plant).
A non-native species that has established a self-sustaining population in the wild, often without human help.
Species that have become naturalized. Often used for plants that now grow wild. Neutral to slightly negative connotation in ecology.
Dandelions have spread in Japan as a naturalized species.
Literally 'established non-native species'. Used in technical ecology to describe species that have successfully established in a new environment.
外来種 is the broadest term for any species from outside. 移入種 emphasizes human introduction, often intentionally. 帰化種 refers to species that have become established and reproduce in the wild. In everyday speech, 外来種 is sufficient; in scientific writing, choose based on the nuance of introduction and establishment.
Do not translate 'non-native species' word-for-word as 非在来種 or 非土着種. These are not natural Japanese. Use 外来種 or context-appropriate alternatives.
Raccoons are designated as an invasive alien species.
Eradication of harmful non-native species is underway.
外来魚が在来魚を駆逐している。
Non-native fish are driving out native fish.
Management of established non-native species is an issue.