Elizabeta Briski - Invasion Ecology Group

Increase in transport network and demand for commodities have accelerated the unintentional introduction of

non-indigenous species beyond their native ranges in both terrestrial and aquatic habitats worldwide. Commercial vessels

transport over 90% of the world’s trade and are a leading mechanism for spread of aquatic species. Diversified species

are transported fouled on ships’ external surfaces or in ballast water and sediment inside ballast tanks.

Ballast water and sediment contain large numbers of active

invertebrates as well as their viable dormant eggs.

Diversified invertebrate taxa, such as rotifers, cladocerans

and copepods are friquently found in ballast tanks.

Ballast water, typically utilized to control the trim and 

stability of a vessel when a vessel is not fully loaded with

cargo, can contain significant amounts of suspended

sediment that later settles to the tank's bottom. Amount of

sediment carried by ship can vary from < 1 to > 150 tonnes.

Macroinvertebrates, for instance comb jelly Mnemiopsis

leidyi or bloody red shrimp Hemimysis anomala, as well

as chordates such as golden star tunicate Botryllus

schlosseri, may also be transported in ship ballast waters.

The European green crab Carcinus maenas and mud

crab Rhithropanopeus harrisii are generalist predators that

are attributed with the decline of other crab and bivalve

species. Depending on species, female crab may carry

from several thousand up to two million eggs in single

clutch increasing propagule pressure and establishment

success of taxa greatly.   

The fishhook waterflea Cercopagi pengoi and spiny

waterflea Bythotrephes longimanus are non-indigenous

species of global concern. They are notorious predators

and may suppress both invertebrate and vertebrate taxa.

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