Background information and definitions
Non-native, invasive and other problematic species can impact on native subtidal benthic invertebrate species through predation, competition for resources (food & space), contamination (for pathogens and diseases), or hybridization (through reproduction) (Molnar et al. 2008; Bishop et al. 2010). Ballasting is the process by which sea water (ballast water) is taken in and out of the ship when the ship is at port or at sea. Ballast water can therefore contain species from one location taken-up during water intake, which are then accidentally released in a new environment during de-ballasting (water release). Ballast water is one of the major processes of introduction of non-native, invasive and problematic species (Barry et al. 2008; Hewitt 2003; Hewitt et al. 2004; Molnar et al. 2008). Treating ballast waters before exchange can potentially eliminate most or all risks of accidental introduction of non-native, invasive or other problematic species (Reise et al. 1998). Treating ballast waters can be done through either mechanical–physical or chemical processes, for instance using high-performance filters, oxidizing or disinfecting chemicals, or Ultra-Violet radiations (Werschkun et al. 2014).
Related evidence is summarised under “Threat: Invasive and other problematic species, genes and diseases – Limit, cease or prohibit ballast water exchange in specific areas”.
Barry S.C., Hayes K.R., Hewitt C.L., Behrens H.L., Dragsund E. & Bakke S.M. (2008) Ballast water risk assessment: principles, processes and methods. ICES Journal of Marine Science, 65, 121–131.
Bishop M.J., Krassoi F.R., McPherson R.G., Brown K.R., Summerhayes S.A., Wilkie E.M. & O’Connor W.A. (2010) Change in wild-oyster assemblages of Port Stephens, NSW, Australia, since commencement of non-native Pacific oyster (Crassostrea gigas) aquaculture. Marine and Freshwater Research, 61, 714–723.
Hewitt C.L. (2003). Marine biosecurity issues in the world oceans: global activities and Australian directions. Ocean Yearbook, 17, 193–212.
Hewitt C.L., Campbell M.L., Thresher R.E., Martin R.B., Boyd S., Cohen B.F., Currie D.R., Gomon M.F., Keough M.J., Lewis J.A., Lockett M.M., Mays N., McArthur M.A., O’Hara T.D., Poore G.C.B., Ross D.J., Storey M., Watson J.E. & Wilson R.S. (2004) Introduced and cryptogenic species in Port Phillip Bay, Victoria, Australia. Marine Biology, 144, 183–202. Molnar J.L., Gamboa R.L., Revenga C. & Spalding M.D. (2008) Assessing the global threat of invasive species to marine biodiversity. Frontiers in Ecology and the Environment, 6, 485–492.
Reise K., Gollasch S. & Wolff W.J. (1998) Introduced marine species of the North Sea coasts. Helgoländer Meeresuntersuchungen, 52, 219.
Werschkun B., Banerji S., Basurko O.C., David M., Fuhr F., Gollasch S., Grummt T., Haarich M., Jha A.N., Kacan S. & Kehrer A. (2014) Emerging risks from ballast water treatment: The run-up to the International Ballast Water Management Convention. Chemosphere, 112, 256–266.