Maritime traffic connects Antarctic fragile coasts with ecosystems around the world

Importance

The movements of vessels related to fishing, tourism, research and supply expose the Antarctic continent to human impacts. Until now, only rough estimates or industry-specific information have been available to inform evidence-based policies aimed at mitigating the introduction of non-native marine species. The Southern Ocean of Antarctica is home to a unique biota and is the only marine region in the world without any known biological invasion. However, climate change is removing physiological barriers to potentially invasive alien species and increased vessel activity is increasing propagule pressure. The successful conservation of Antarctic iconic species and environments relies on combating climate change and direct, localized human impact. We have identified high risk areas for introduced species and are providing critical data that will underpin better evidence-based management in the region.

Summary

Antarctica, an isolated wilderness long considered pristine, is increasingly exposed to the negative effects of human activity carried by ships, and in particular the introduction of invasive species. Here, we provide a comprehensive quantitative analysis of vessel movements in Antarctic waters and a spatially explicit assessment of the risk of introducing non-native marine species into all Antarctic waters. We show that ships cross the natural insulating barriers of Antarctica, connecting it directly via a vast network of maritime activities to all regions of the world, in particular the ports of the South Atlantic and Europe. Ship visits are more than seven times higher in the Antarctic Peninsula (particularly east of Anvers Island) and the South Shetland Islands than elsewhere around Antarctica, together accounting for 88% of visits in the Southern Ocean ecoregions. Contrary to expectations, we show that while the five recognized ‘Antarctic carrier cities’ were important last ports of call, especially for research and tourist vessels, 53 additional ports had ships leaving directly to the Antarctica from 2014 to 2018. We identify ports outside of Antarctica. where biosecurity interventions could be most effectively implemented and the most vulnerable places in Antarctica where surveillance programs for high-risk invaders should be established.

Footnotes

    • Accepted November 1, 2021.
  • Author contributions: research designed by AHM, LSP and DCA; AHM has done research; AHM analyzed the data; and AHM, LSP and DCA wrote the article.

  • The authors declare no competing interests.

  • This article is a direct PNAS submission.

  • This article contains additional information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2110303118/-/DCSupplemental.

Data availability

Data supporting the conclusions of this study are available from LLI, but restrictions apply. The data has been used under license for this study and is therefore not publicly available. The processed and summarized data may be available from the authors upon reasonable request and with the permission of LLI. The code used to analyze the data from this study is kept in a GitHub repository; access and code are available on request.

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