This site is maintained by the Department of Natural Resources . Non-native species are recognized to be a major threat to ecosystem health. However, the impact of any particular introduced species cannot be predicted. Its impact will depend on how it interacts with the local environment.
Introductions can have positive, neutral or negative effects.
Some introductions prove to be catastrophic. The ecological effects of introductions can be even more severe than the economic effects, although they are often more difficult to assess. Species have been introduced to Puget Sound through shipping, aquaculture and other human activities. These species and their effects on the ecosystem are comparatively well understood. In contrast, most alien species in Puget Sound are neither recognized nor known.