Marine biodiversity offsets: Pragmatic approaches toward better conservation outcomes

Increasing exploitation of marine natural resources and expansion of energy infrastructure, shipping, and aquaculture across the oceans are placing increased pressure on marine life. Biodiversity offsets, as the last stage of the mitigation hierarchy, provide an opportunity to promote a more sustainable basis for development by addressing residual impacts and achieving "no net loss" for biodiversity. Despite debate around their effectiveness, biodiversity offsets are seeing increasing application on land but remain a rarely used tool in the marine environment. We assess how offsets can be applied in the marine environment to achieve better biodiversity outcomes, and identify implications for conservation policy and practice. For instance, spatial conservation planning provides opportunities to move away from a siloed, project-by-project, approach by pooling offsets on a regional scale. There are real differences between marine and terrestrial environments in relation to ecology, connectivity, data availability, management options, and impact perception, and marine offsets are therefore often regarded as challenging. However, fundamental offset principles, types, and approaches apply equally on land and at sea. Marine biodiversity offset approaches can build on the experience of terrestrial offsets but can also innovate to help achieve biodiversity gains and contribute toward global and national biodiversity targets.