The Western Mediterranean Sea found to be one of the areas with the highest reduction in marine traffic during the COVID-19 pandemic

  • Researchers monitor and map for the first time the response of shipping to the COVID-19 sudden global disruption in near real-time using satellite data.
  • Published in Nature Communications, this study provides a comprehensive overview of how mobility restrictions have impacted marine traffic, particularly in the Western Mediterranean Sea, where shipping activities drop by 62.2% during mid-April 2020, compared to the same period in 2019.
  • Quantifying the changes in human activities at sea paves the way to research the impacts of COVID-19 on the blue economy and ocean health.

The coronavirus disease pandemic has resulted in unparalleled global health and socio-economic impacts, with many countries implementing mobility restrictions to control the spread of the virus. Current research shows that it has led to reductions in transport, energy consumption, and consumer demand resulting in significant changes in the scale and extent of human impacts on the natural environment. In the ocean, these restrictions on human mobility have impacted ship-based activities.

Now, researchers from the University of Exeter (UK), the Balearic Islands Coastal Observing and Forecasting System (SOCIB), and the Mediterranean Institute for Advanced Studies - IMEDEA (CSIC-UIB), (both in Spain), have published a work showing the impacts of COVID-19 on global and Mediterranean Sea’s marine traffic. This study paves the way for future research on the potential effects of mobility restrictions on the blue economy and ocean health.

Marine traffic changes

“In order to provide a comprehensive overview of the impacts of the multiple lockdowns, we have monitored and mapped for the first time the response of shipping to such a sudden global disruption in near real-time using satellite data,” explains Joaquín Tintoré, director of SOCIB, Research Professor from CSIC at IMEDEA (CSIC-UIB) and co-author of the study. “Our data-driven approach shows that this has led to an unprecedented impact at global and regional scales across all sectors, leading to a general decrease in marine traffic, especially in the Western Mediterranean Sea, one of the areas with the highest reduction,” he adds.

Published in the journal Nature Communications, the study shows that “in global terms, there were decreases in 70.2% of Exclusive Economic Zones (up to 200 nautical miles offshore) of the 124 countries included in the study, but changes varied spatially and temporally in alignment with confinement measures during the first half of 2020, relative to the same period in 2019,” according to David March, researcher at the University of Exeter and first author of the study. Overall, “global declines peaked in April, with a reduction in traffic occupancy of 1.4% and decreases found across all ship categories (i.e. cargo, tankers, fishing, service, recreational and passenger vessels), showing a more marked and longer-lasting decrease in passenger vessels,” he adds.

An in-depth look at the Mediterranean

In addition, the researchers have conducted a regional assessment in the Western Mediterranean Sea (i.e. Spain, France, Italy). “To capture short-term responses due to lockdown effects at the finer temporal resolution, we used real-time, long-term data from land-based antennas,” says Tintoré. Also, “in contrast to our global analysis, we considered recreational boats, which constitutes an important sector in one of the world's tourism hotspots,” he adds.

Temporal variation of all vessel types in the Western Mediterranean during COVID-19. Daily data of vessels underway within the coastal zone (24 nautical miles) of EU countries present in the study area (i.e., Spain, France, Italy). The shaded area represents the difference between 2019 and 2020 (from 1st January until 30th November). The vertical dotted line represents the World Health Organization pandemic declaration on the 11th March 2020.

Temporal variation of all vessel types in the Western Mediterranean during COVID-19. Daily data of vessels underway within the coastal zone (24 nautical miles) of EU countries present in the study area (i.e., Spain, France, Italy). The shaded area represents the difference between 2019 and 2020 (from 1st January until 30th November). The vertical dotted line represents the World Health Organization pandemic declaration on the 11th March 2020.

According to the researchers, when comparing the 2020 (January 1-November 30) period to the equivalent in 2019, the number of vessels sharply decreased in the first days of restrictions, reaching an overall median drop of 51% during the initial lockdowns (March-June). Reductions were rapid and profound for all categories other than cargo and tankers vessels, for which reductions were not apparent until May. In particular, “maximal reductions ranged from 22.2% (tankers) to 93.7% (recreational boats), with a maximal overall drop across all categories of 62.2% during mid-April, while passenger vessels presented the highest median drop (47.5%),” highlights March. Regarding the recovery rate, the study found that cargo, tanker, and fishing vessels showed a relatively swift recovery in vessel activity. In contrast, passenger and recreational vessels remained at low levels throughout the lockdown period. After easing restrictions, merchant and fishing vessels were close to pre-lockdown values. Recreational boats exhibited a fast recovery and rebounded their activity from mid-July until mid-September, while passenger vessels remained at low levels despite a recovery during the summer months.

Temporal variation of vessels in the Western Mediterranean during COVID-19. Daily data of vessels underway within the coastal zone (24 nautical miles) of EU countries present in the study area (i.e., Spain, France, Italy) per vessel category: (a) cargo, (b) tanker, (c) passenger, (d) fishing, (e) recreational, and (f) others. The shaded area represents the difference between 2019 and 2020 (from 1st January until 30th November). The vertical dotted line represents the World Health Organization pandemic declaration on the 11th March 2020.

Temporal variation of vessels in the Western Mediterranean during COVID-19. Daily data of vessels underway within the coastal zone (24 nautical miles) of EU countries present in the study area (i.e., Spain, France, Italy) per vessel category: (a) cargo, (b) tanker, (c) passenger, (d) fishing, (e) recreational, and (f) others. The shaded area represents the difference between 2019 and 2020 (from 1st January until 30th November). The vertical dotted line represents the World Health Organization pandemic declaration on the 11th March 2020.

Overall, these results provide guidance for large scale monitoring of the effects of COVID-19 on marine traffic that may subsequently influence the blue economy and ocean health.

  • Reference article

March, D., Metcalfe, K., Tintoré, J., & Godley, B. J. (2021). Tracking the global reduction of marine traffic during the COVID-19 pandemic. Nature Communications, 12(1), 1-12.
http://dx.doi.org/10.1038/s41467-021-22423-6