Assessing the importance of biological uncertainties to the control of species introductions via ballast water.

摘要

Biological invasions are increasingly altering the ecology and evolutionary processes of biological communities. In marine and coastal environments, commercial shipping ballast water is considered to be the most relevant transfer vector of invasions worldwide. The current regulation of biological invasions rests on risk assessment procedures that are narrowly focused, subjective, often arbitrary and unquantified, and subject to political interference. Here, we present an innovative decision support framework, based on a comprehensive, quantitative, and objective analysis, which can provide coastal managers with the necessary information to reduce biological introductions via ballast water. The traditional deterministic exponential population dynamics model is reviewed and a more suitable population dynamics model for populations entrained in ballast water is proposed. The use of ocean color satellite images to assist in the management of ballast water is explored, and the methodology is used to simulate the allocation of treatment efficacy for vessels that discharged ballast water in the Delaware Bay in the years 2003 and 2004. The resulting analysis identifies the sources of biological uncertainty related to this issue, including the disproportional lenience given to phytoplankton concentrations under the IMO's BWC performance standards, and bounds the problem by characterizing best and worst case scenarios under variable biological and management circumstances.