| Example Species
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The term “vector” represents both pathways and mechanisms for introducing a species into a new environment. Nonindigenous species are intentionally introduced by “stocking” ponds, dumping aquaria, and releasing organisms for the purpose of controlling others (biocontrol). Vectors facilitating the unintentional transport or release of species include escapees from aquaculture, live bait and its packing materials, and algae and fouling organisms on boat hulls and anchors. One of the most important vectors for unintentional introduction is ballast water. |
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Nearly
70% of the 160 species that have invaded the Great Lakes originated
in the Ponto-Capsian region of Eastern Europe (Black, Azov, and Caspian
Seas) (5). Reid and Orlova (6)
suggest that this region is an important donor sight because the
endemic
species have wide environmental tolerances (including a wide range
of salinity)
and high phenotypic variability. The arrival of these invasive species
was facilitated by increases in ship traffic, ship speed, and ballast
water discharge (1). Nearly 30% of
the current invasive species became established following the opening
of the St. Lawrence
Seaway
in 1959 and the subsequent intensification of traffic in the Great
Lakes (7). |
