Marine seismic surveys are a fundamental tool for geological mapping, including the exploration for offshore oil and gas resources, but the sound generated during these surveys is an acute source of noise in the marine environment. Growing concern and increasing scientific evidence about the potential impacts of underwater noise associated with marine seismic surveys presents an interdisciplinary challenge to multiple sectors including government, industries, scientists and environmental managers. To inform this issue, Geoscience Australia, in collaboration with Curtin University and CSIRO, published a literature review (Carroll et al. 2017) that summarised 70 peer-reviewed scientific studies that investigated the impacts of impulsive low-frequency sound on marine fish and invertebrates. Here we provide an updated, critical synthesis of recently published data to ensure that the Australian governments’ understanding of the potential impacts of seismic surveys on fisheries and the broader marine environment remains current. A significant body of scientific research into the effects of marine seismic sounds on the marine environment has been undertaken over the past four years and scientific knowledge in this area is continuing to improve. This is partly due to increased sophistication of experimental designs that integrate the controlled aspects of laboratory studies, with field-based (before-after-control-impact) studies. However, there remain several research issues and challenges associated with progressing our understanding of the full impact of marine seismic surveys on fisheries and the marine environment. These include the need to broaden the research to cover a wider range of marine species, and to expand our understanding to impacts at the population and ecosystem scale, rather than the individual organism. There is also a continued need for improved standardisation in terminology and measurement of sound exposure. To address the research gaps and issues, Geoscience Australia recommends measures including: 1) undertaking additional multidisciplinary co-designed scientific research to examine short and long term impacts on important life stages of key species (including protected and commercially important species); 2) gathering robust environmental baselines and time-series data to account for spatiotemporal variability in the marine environment and to help inform management and monitoring; 3) continuing to develop and refine standards for quantifying sound exposure; 4) modelling population and ecosystem consequences, and; 5) further studying the interaction of seismic signals with other stressors to better assess cumulative impacts. If applied these recommendations may advance the scientific evidence-base to better inform stakeholder engagement, environmental impact assessment and management of the potential impacts of seismic surveys on fisheries and the marine environment.

Our knowledge of life at the Antarctic sea-bed has increased in the past decades with increasing ship-based surveys and monitoring sites, new technologies and data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that limits our ability to assess the state of the Southern Ocean benthos on larger scales. The seafloor communities that inhabit the Antarctic shelf are often diversity hotspots. These habitats are important in the generation of ‘blue carbon’ and habitat for commercial fish species, for this reason we focus on these habitats. Many Southern Ocean seafloor habitats and their communities seem to be especially vulnerable to certain drivers of change including increasing ocean temperatures, iceberg scour, sea-ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include those experiencing rapid regional warming and increased iceberg-scouring e.g. the West Antarctic Peninsula; where human activities and environmental conditions increase the potential for the establishment of non-indigenous species e.g. sub-Antarctic islands and tourist destinations and areas with fishing activities e.g. around South Georgia, Heard and MacDonald Islands. Vulnerable species include calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat forming species that can be damaged by fishing gears e.g. sponges, bryozoan and coral species. Management regimes can protect seafloor habitats and key species from fishing activities but only if they consider specific traits, such as longevity, food availability, their physiological adaptation and rare or common occurrences. Ecosystem-based management practices and long-term protected areas may be the most effective in the preservation of vulnerable seafloor habitats. However, action is needed to reduce carbon emissions to limit the impact of increasing ocean temperatures and ocean acidification. We focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change and fishing pressures. <b>Citation:</b> Brasier MJ, Barnes D, Bax N, Brandt A, Christianson AB, Constable AJ, Downey R, Figuerola B, Griffiths H, Gutt J, Lockhart S, Morley SA, Post AL, Van de Putte A, Saeedi H, Stark JS, Sumner M and Waller CL (2021) Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change. <i>Front. Mar. Sci.</i> 8:622721. doi: 10.3389/fmars.2021.622721