We reviewed existing guidelines on conducting environmental impact assessments for offshore mining projects, to analyze gaps between the guidance and actual implementation of published environmental impact statements. In cases of benthic fauna, the implementation of survey subjects did not fully correspond to those described in the guidelines. We estimated that these differences mainly stemmed from three elements: maturity of techniques, cost-effectiveness, and usability for evaluation of impacts.
In recent years, as commercial offshore mining has become realistic, there have been moves to implement Environmental Impact Assessments (EIA) and to develop accompanying frameworks, in both internal and external areas of national jurisdiction.
Attempts to develop standards for appropriate EIA started with establishing guidelines on the prospecting and exploration phases at areas beyond national jurisdiction (the Area), issued by the International Seabed Authority (ISA, 2002). More recently, regional and national organizations such as The Pacific Community (SPC) and National Institute of Water and Atmospheric Research, Ltd. in New Zealand (NIWA) have also published guidelines for EIA in national jurisdictions (Swaddling, 2016; Clark et al, 2017). In addition, various considerations related to EIA are being conducted, and efforts are being made to clarify the impacts of offshore mining and to develop the necessary technologies for evaluation (see MIDAS website; SIP website). In particular, benthic fauna, as one of the communities most impacted by offshore mining, have been examined in many reports. However, there are no critical standards that can be applied to EIA in both internal and external areas of national jurisdiction. On the other hand, offshore mining projects are planned in national jurisdictions, some of which have already conducted EIA. However, in the absence of critical standards, organizations may have set their own survey contents. Moreover, EIAs have differed in many aspects, such as their periods of implementation, targeted mineral species, and depth of mining area. These disparities may have also contributed to the differing survey subjects among the projects. Under these circumstances, it is likely that the requirements of EIA differ, between administrators and mining entities. In New Zealand, two offshore mining projects have implemented EIA (CRP, 2014; TTR, 2013). However, in both cases, their initial applications were refused by the Environmental Protection Authority (EPA), as their Environmental Impact Statements (EIS) involved considerable uncertainty, and adequate assessments were not conducted (EPA, 2014; EPA, 2015). It is likely that the rejection of such proposals is a consequence of the differing viewpoints on EIA between the concerned parties. It is conceivable that the views of administrators are reflected in the guidelines, whereas those of the commercial entities are reflected in the resulting EIS. To identify the gaps between administrators and commercial entities, it is necessary to compare the subjects specified in guidelines with those actually implemented in EIS.
