tramp species Species that have been spread around the world inadvertently by human commerce. For example, the brown weed Sargassum muticum (japweed or strangleweed) was inadvertently introduced into British coastal waters, probably with the importation of the Japanese oyster (Crassostrea gigas); its common name refers to its effects on pipes and outboard engines. Eichhornia crassipes (water hyacinth), taken to the USA from Venezuela by Japanese exhibitors at the 1884 Cotton Exposition in New Orleans, escaped and is now a serious weed of many rivers in low latitudes throughout the world. The brown rat (Rattus norvegicus), originally from south-east Asia, and the house mouse (Mus musculus), originally from the Russian–Turkish border region, are well known animal examples.

tramp species Species that have been spread around the world inadvertently by human commerce. For example, the brown weed Sargassum muticum (japweed or strangleweed) was inadvertently introduced into British coastal waters, probably with the importation of the Japanese oyster (Crassostrea gigas); its common name refers to its effects on pipes and outboard engines. Eichhornia crassipes (water hyacinth), taken to the USA from Venezuela by Japanese exhibitors at the 1884 Cotton Exposition in New Orleans, escaped and is now a serious weed of many rivers in low latitudes throughout the world.

tramp species Species that have been spread around the world inadvertently by human commerce. See also SUPERTRAMP.