Ballast water risk assessment: principles, processes, and methods

Abstract

Barry, S. C., Hayes, K. R., Hewitt, C. L., Behrens, H. L., Dragsund, E., and Bakke, S. M. 2008. Ballast water risk assessment: principles, processes, and methods. – ICES Journal of Marine Science, 65: 121–131. Two methods of assessing the risk of species introduction by ballast water are discussed, species-specific and environmental similarity assessments, each for alignment with four proposed principles of risk-based resource management: (i) society accepts that low risk scenarios exist; (ii) risk assessment is capable of identifying low risk scenarios; (iii) risk mitigation strategies exist; and (iv) mitigation costs are less than the cost of performing risk assessment. All four principles were met in some circumstances for both methods. Species-specific ballast water risk assessment is best suited to situations where the assessment can be restricted to a limited set of harmful species on journeys within bioregions where ballast water is a small component of natural genetic exchange. Environmental similarity risk assessment is appropriate for journeys that start and end in locations which have very little or no natural genetic exchange, such as journeys between non-contiguous bioregions. Because a large number of species are not assessed individually, environmental match assessments necessarily will be restricted to fundamental variables such as temperature and salinity. A number of bioregion classifications have been identified in the world’s oceans, some of which at a scale that may be appropriate for ballast water management. The suitability of any particular classification, however, needs further examination.

Temporal development of hull-fouling assemblages associated with an Antarctic supply vessel

“…The ecological and economic impacts of species introduced with ballast water are so extensive that substantial legislation exists to reduce the flow of introductions via this pathway (Ruiz et al 2000, Hewitt & Campbell 2007, Barry et al 2008. Principally, this involves the International Convention on the Control and Management of Ship's Ballast Water and Sediments (IMO 2004).…”

Ballast Water Risk Indication for the North Sea

“…This approach includes species-specific data on the minimum requirements of a species to survive, to reproduce, and therefore to spread in both donor and recipient areas. The species-specific approach requires detailed data, since the risk of single species is being assessed (Barry et al 2008). A detailed approach to risk assessment requires more data, time, and effort.…”

Management strategies to prevent the introduction of non-indigenous aquatic species in response to the Ballast Water Convention in Taiwan

“…It can be seen then, based on the G7 biogeographic region and environmental similarity criteria, that only preliminary risk ranking can be made, and not meticulous ranking of risk levels, since a large percentage of arriving ships came from the same biogeographic regions or similar environment. If all of these ships need to go through the G7 species-specific risk assessment, it will entail great expenses for the port states; considering the financial and manpower burden, it is hardly a feasible practice [38].…”