Risk assessment framework for ballast water introductions

This report describes a quantitative risk assessment framework for ballast water introductions. The framework has been developed to help meet the objectives of the national Ballast Water management Strategy, established by the Australian Quarantine and Inspection Service (AQIS) in 1995. The risk assessment framework is modelled on the internationally endorsed, import risk assessment framework, and the Quantitative Risk Assessment (QRA) paradigm. The risk analysis component of the framework consists of five modules that deal with discrete elements of the ballast water introduction cycle, up to the point of introduction and survival of a non-native species in a new port (the assessment endpoint). The framework is species and vessel specific. In the first instance it will be applied to a target list of marine pests, whose introduction or spread in Australian waters is to be avoided. Species-specific assessments of this kind are appropriate for quarantine purposes, and are the only effective way to approach ballast water risks. The framework allows an assessment of ballast water risk to be made at several levels of complexity, depending on the availability of data. At its simplest level the framework provides a qualitative hazard ranking scheme that will allow AQIS to allocate its vessel sampling resources in the most cost effective manner. At its most complex level the framework estimates the likelihood that a particular vessel is contaminated with a target species, and the probability that these organisms will survive if discharged into a port. The framework can therefore be used to assess the benefits of alternative ballast water management schemes. The framework identifies the conditions under which vessel's ballast water becomes contaminated with target species. This will allow a pro-active response to the marine pest hazard in individual ports in order to minimise the likelihood of vessel infection