A global market in seafood disperses many live organisms to distant locations. These organisms can be released into environments of the new locations, where they can establish reproductive populations. The risks of such introductions remain poorly resolved. We therefore surveyed bivalves ( oysters, mussels, and clams ) that are commercially available as seafood in the western United States. Twenty-four of the 37 available marine and estuarine bivalve species are nonindigenous. Eleven of these 24 nonindigenous species have established, self-sustaining populations in northeast Pacific environments. Three of the remaining 13 nonindigenous species have been introduced outside their natural ranges elsewhere in the world. We estimated the risks of some of these species being introduced by performing binomial probability analyses on these data. Our results suggest that there is a significant risk of introducing live seafood species into northeast Pacific ecosystems. Efforts to warn distributors and consumers to screen imported seafood species for invasiveness, to monitor estuaries and coastal ecosystems for early detection, and to develop rapid-response plans for containing new invaders are warranted. |
