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PW17 Control and Regulation of Non-idigenous Species
(PW265) Examination of mesozooplankton present in ballast water of ships entering Puget Sound, Washington.
Cordell, J1, Ferm, N1, Grocock, J1, Perrins, J1, Herwig, R1, 1 University of Washington, Seattle, WA, United States
ABSTRACT- Large quantities of ballast water containing millions of organisms are transported around the world each year by commercial vessels, constituting a major vector for the introduction of non-indigenous aquatic organisms and invasive species. Each year, over 2,000 commercial ships enter Puget Sound, Washington, most of which are bound for the ports of Seattle and Tacoma. Some vessel types, such as bulk cargo ships and tankers, carry and discharge larger quantities of ballast water into Puget Sound than do other types of ships. Often these ships arrive in Puget Sound without cargo and are therefore filled with the maximum amount of ballast water. The discharge of ballast water is regulated in the state of Washington, and all vessels intending to discharge ballast water within Washington waters are required to conduct an open ocean exchange. Vessels making an ocean crossing are required to exchange their ballast water at least 200 nautical miles offshore, and those making a coastal voyage are required to exchange at least 50 nautical miles offshore. Ships may perform an oceanic exchange using either an empty-refill or flow-through exchange. We have boarded over 75 vessels and examined the composition of the mesozooplankton present in a ballast tank for each ship. Zooplankton were classified as being nearshore, offshore, indigenous to the northeast Pacific region, non-indigenous to the northeast Pacific regions, or of unknown origin. We were provided the ship′s information as to the extent and location of their open ocean exchange. The composition and the suggested origins of the mesozooplankton vary between ships. Although we cannot directly determine the percent of the oceanic exchange for each ship, our results suggested that large numbers of coastal and/or non-indigenous organisms continued to be introduced despite the reported attempts to perform oceanic exchanges on ships that enter Puget Sound.
Key words: zooplankton, ballast water, non-indigenous species
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