title: Combining Ballast Water Exchange and Treatment To Maximize Prevention of Species Introductions to Freshwater Ecosystems.
abstract: The most effective way to manage species transfers is to prevent their introduction via vector regulation. Soon, international ships will be required to meet numeric ballast discharge standards using ballast water treatment (BWT) systems, and ballast water exchange (BWE), currently required by several countries, will be phased out. However, there are concerns that BWT systems may not function reliably in fresh and/or turbid water. A land-based evaluation of simulated "BWE plus BWT" versus "BWT alone" demonstrated potential benefits of combining BWE with BWT for protection of freshwater ecosystems. We conducted ship-based testing to compare the efficacy of "BWE plus BWT" versus "BWT alone" on voyages starting with freshwater ballast. We tested the hypotheses that there is an additional effect of "BWE plus BWT" compared to "BWT alone" on the reduction of plankton, and that taxa remaining after "BWE plus BWT" will be marine (low risk for establishment at freshwater recipient ports). Our study found that BWE has significant additional effect on the reduction of plankton, and this effect increases with initial abundance. As per expectations, "BWT alone" tanks contained higher risk freshwater or euryhaline taxa at discharge, while "BWE plus BWT" tanks contained mostly lower risk marine taxa unlikely to survive in recipient freshwater ecosystems.
authors.affiliation: †GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.|‡Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, L7S 1A1, Canada.
authors.forename: Elizabeta
authors.initials: E
authors.lastname: Briski
authors.affiliation: §Gollasch Consulting, Grosse Brunnenstrasse 61, 22763 Hamburg, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Gollasch
authors.affiliation: ∥Dr. Matej David Consult, Korte 13e, 6310 Izola, Slovenia.
authors.forename: Matej
authors.initials: M
authors.lastname: David
authors.affiliation: ‡Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, L7S 1A1, Canada.
authors.forename: R Dallas
authors.initials: RD
authors.lastname: Linley
authors.affiliation: ‡Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, L7S 1A1, Canada.
authors.forename: Oscar
authors.initials: O
authors.lastname: Casas-Monroy
authors.affiliation: ‡Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, L7S 1A1, Canada.
authors.forename: Harshana
authors.initials: H
authors.lastname: Rajakaruna
authors.affiliation: ‡Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, L7S 1A1, Canada.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Bailey
mesh_terms: D000818:Animals; D017753:Ecosystem; D005618:Fresh Water; D058865:Introduced Species; D010839:Phytoplankton; D012767:Ships; D018508:Water Purification / Q000379:methods*; D015048:Zooplankton