Study uses AIS data to investigate how ships affect underwater wildlife

/ Author: Karel Feenstra
Coral reef on Bonaire
© © Stephen Frink/Corbis
Some 90% of all the products traded around the world are transported by ship. As international shipping traffic continues to increase, it becomes ever more important to investigate what impact ships have on the creatures that live along the busiest shipping routes. Hannah Langerveld, a researcher at Tilburg University, used her time as an intern at Statistics Netherlands (CBS) to interpret international Automatic Identification System (AIS) data through a combination of methods. Her findings, which are described in her bachelor’s degree thesis, are of great interest to actors both in the Netherlands and around the world.

Partnering with universities and universities of applied science

‘This study brought several different things together,’ says CBS Innovation Manager Barteld Braaksma. ‘At CBS we research various external data sources, such as the AIS data from the United Nations’ (UN) Global Data Platform. That helps us familiarise ourselves with new datasets, but most of all it lets us investigate how we can use that information in combination with relevant knowledge to tackle social issues. We were also keen to work with data in the Dutch Caribbean, as we also operate there from our Caribbean office.’ The research was conducted in the form of an internship assignment that brought together both the UN’s Global Data Platform and Tilburg University. CBS is increasingly joining forces with universities in collaborative relationships that attract talented scientists to work at CBS. This ‘outsider perspective’ boosts the development of innovative research methods and helps improve existing statistics.

Fascinating and relevant

The research into AIS data was conducted by Hannah Langerveld, a student at Tilburg University, together with CBS researcher Henk van de Velden who lives and works on the Caribbean island of Bonaire. Langerveld was given the freedom to formulate her own research question and do the research she was interested in. ‘I really wanted to study underwater wildlife,’ she explains. ‘I’m fascinated by shipping and its effect on the maritime ecosystem of coral, and that’s a relevant topic. We know that the noise from shipping, especially intensive shipping, affects underwater life, but we don’t know the exact nature or extent of that impact. You can do underwater research using a hydrophone, but that’s a very intensive method that can only be used in localised studies, and it doesn’t even generate much information. AIS gives us a lot of information about shipping. The question we asked ourselves was: can we use those data to form conclusions about the underwater noise caused by shipping?’

Hannah Langerveld conducted research at CBS into the impact of ships on underwater wildlife

Hannah Langerveld conducted research at CBS into the impact of ships on underwater wildlife

Up-to-date information on ships

AIS is a global data system that provides up-to-date information on ships’ locations. The system is based on transponder technology and aims to increase the safety of maritime and inland shipping. AIS has been the standard for marine navigation since 2003, with the system being installed on all ships above a certain size. As Ivo Havinga explains, the UN’s Global Data Platform unlocks these data, making them accessible to statistical offices around the world. Until his retirement in October 2021, Havinga was the Head of Economic Statistics at the UN in New York and his portfolio included international statistical standards for national economic and environmental accounts, the use of digital data for official statistics, and research into broader well-being accounts. ‘We have a range of ways to try to promote the use of those data,’ he adds. ‘For example, we organise hackathons and help researchers get comfortable with using the data.’

Shipping and underwater noise

Langerveld studied the AIS data in relation to factors such as source level, ‘path smoothing’ of underwater sound waves, the wide variety of ship models and the specific sound characteristics associated with those models. She concluded that the variables remain within the margin of error. This means that AIS data can serve as an indicative source when identifying areas with a high level of underwater ship noise. Although she initially intended to research the impact of ship noise on underwater wildlife, the complexity of the subject matter forced Langerveld to significantly scale back the study to focus on the relationship between AIS data and underwater noise. After processing the first datasets using a new method, she discovered that a slight reduction in average sailing speed was associated with a relatively larger reduction in underwater noise. This finding could have great relevance to global shipping practices. Van de Velden praised both the quality of Langerveld’s research and her methodology. ‘She’s very self-sufficient, and she wrote all the code for her research herself. That’s a big deal.’

International importance

‘Small island development states’ are of specific interest to the UN. The UN aims to help these states develop good statistical knowledge about the economy, goods transport, employment and CO2 emissions. ‘This knowledge will help them make long-term policy choices,’ Havinga explains. For example, AIS data can tell us a lot about maritime transport both to and between islands, whether for cargo or for tourism. When these data are combined with import and export data from the customs service, they provide a better understanding of local economic trends and developments. ‘And there are other concerns in the Antilles,’ says Van de Velden. ‘Both Greenpeace and local people themselves are going to court to demand better climate policies. Human actions have a big impact on nature, both on land and in the water. Viewed in that light, this study has the potential to be a treasure trove of new factual information.’ Havinga fully endorses the importance of the research. ‘This study by Langerveld and CBS is of great interest, on an international scale. That importance is mainly due to the research methods they developed, which can now be used by other countries to do similar studies.’