A Shift Towards Quantitative Cumulative Impact Assessments for Data Poor Marine Mammal Species: A Novel Approach for the Australian Context

Marine fauna are vulnerable to a variety of acute and chronic stressors that act across varying spatial and temporal scales. The evaluation of the effect of these stressors requires consideration of the key threats and impact pathways, and the cumulative effect of anthropogenic pressures from all aspects of a project in concert with projects and long-term environmental change. Migratory species, particularly those that migrate across jurisdictional boundaries, may be exposed to pressures that compromise the recovery or health of the population that are not manageable under any one country’s legislation. Thus, the evaluation of cumulative impacts in a meaningful manner requires careful consideration of pressures at biologically meaningful spatial and temporal scales. Complex models predicting the population consequence of disturbance are increasingly being used to understand the potential significance of anthropogenic pressures on populations. While incredibly valuable, information to parametrize these models are not available for many species and populations. This chapter presents a semi-quantitative framework for the prediction of cumulative impacts on migratory marine mammal populations, with examples of how this may be applied using the Australian legislative and environmental context.