A mosaic-like compendium of information on the marine biotic environment of the North West Shelf has been compiled from a number of different sources. The areas most valued coincide with those most vulnerable to disturbance. Regulatory authorities require some form of impact assessment to be carried out by oil and gas explorers and producers as a condition of operation. Considerable expenditure is incurred annually by these companies in complying with these requirements, but current assessment methods do not always consider the scale of possible impacts nor the scientific validity of the results. Despite acceptance, and therefore implied approval of these assessments by the regulatory authorities, adjustments should be made to the current methodology to improve the cost effectiveness of the assessments and to improve the scientific validity of the results.Design of environmental impact assessment of exploration and production operations should consider the relative weighting given to potential acute versus chronic impacts. Prediction of possible impacts enables quantifiable relevant parameters for impact assessment to be identified. Monitoring of indicator species is a cost-effective method of detecting acute effects. Community census methods can be used to detect chronic effects.Statistical analysis of data is a vital, yet frequently ignored, aspect of environmental impact assessment, as is the depositing of voucher specimens for future reference. Statistical analysis can be based on either changes in the difference between specific parameters at the impact and control sites, or comparison of variance between sites over time. Decisions regarding sample area and number of sample replicates should be made based on the required precision of the assessment.
Multi-project environmental impact assessment: insights from offshore oil and gas development in Brazil
