Temporal variability of NIS introductions associated with each pathway into Europe's regional seas, since 1949

Note:
The figure shows the variability of NIS introductions associated with each pathway per 6 year period in European Seas, 1949-2017, aggregated by regional sea.

Transport stowaway: moving of live organisms by maritime transport via various vectors: ballast water and sediments (T-S/ballast water), bio-fouling of ships, boats, offshore oil and gas platforms and other water vessels (T-S/hull fouling) and dredging, angling or fishing equipment (T-S/other).
Release in nature: intentional introduction of live alien organisms (e.g. for fishing or hunting in the wild).
Escape from confinement: movement of (potentially) invasive alien species from confinement (e.g. aquaculture).
Transport contaminant: unintentional movement of live organisms as (e.g. pests, through international trade).
Corridor: movement of alien organisms via transport infrastructure (e.g. canals).