59 



We sampled ballast water from 159 

 cargo ships in Coos Bay, Oregon. The 

 ships and their baflast water originated 

 from 25 Japanese ports (9). Plankton from 

 these vessels included 16 animal and 3 

 protist phyla, and 3 plant divisions (Table 

 1). All major and most minor phyla were 

 represented (10), including 47 ordinal or 



higher taxa and a minimum of 367 dis- 

 tinctly identifiable taxa (I/). The su- 

 praspccific diversity demonstrates the wide 

 taxonomic spectrum represented and em- 

 phasizes the broad implications of this 

 phenomenon (12). 



All major marine trophic groups were 

 represented (Table 1) including carnivores. 



herbivores, omnivores, deposit feeders, 

 scavengers, suspension feeders, primary 

 producers, and parasites, although the last 

 were rare. Taxa characteristic of most tem- 

 perate shallow-water marine communities 

 were represented, including those from in- 

 faunal, soft and hard bottom epifaunal, 

 epibiotic, and planktonic habitats. The bal- 



Tabl* 2. Examples of recent invasions probably mediated by tjallast water. 



■Suggested herein as a ballast-mediated invasion tAn alternative means of dispersal includes transport as external fouling on ships' hulls Here v 

 as ephyrae (lor Scyphozoa) and tiydromedusae (tor Hydrozoa) are as fxobabte as transport as louling polyps 



80 SCIENCE • VOL. 261 • 2 JULY 1993 



suggest ttiat transport 



