Ocean News

Space Race

10th February 2022

The ancient art of tracking has taken a technological turn, changing the way that scientists follow animals around our planet. Lauren De Vos explores how technology is being harnessed to change our trajectory towards one of sustainability in our seas.

Finding stillness

It’s a counterintuitive start for a talk by a travel writer. But when Pico Iyer, British essayist and the author of the book The Art of Stillness: Adventures in Going Nowhere, ruminates, ‘I found that the best way that I could develop more appreciative and more attentive eyes, was, oddly, by going nowhere. Just by sitting still,’ I pause. Revisiting Iyer’s 2014 TED Talk in the year 2020 found me listening to his well-worn words anew.

Pop-up tags are attached to animals that don't often surface and they record things like depth and temperature before detaching, floating to the surface and transmitting their data. Photo © Brendan Talwar

If any year is going to give credence to the counterintuitive, it’s 2020. The global Covid-19 pandemic forced more people into an uncomfortable stillness than any we have collectively known before. But Iyer’s gentle assertions are more pertinent now than ever. He reminds us that ‘still’ isn’t necessarily the same as ‘static’ or ‘stationary’ and that meditation doesn’t preclude movement. Instead, reflection ‘allows you to bring stillness into the motion and connection of the world’. As a biologist, I have long grappled with the idea that with movement comes momentum. And increasingly, much of our work is to understand what this unchecked momentum of humanity’s innovation has meant for biodiversity and our sustainable future.

At some point in this forced global moment of pause, many of us reflected for the first time on what our connected and hugely consumptive lives mean for the earth. For most, it was a first glimpse at how the absence of a human footprint might appear. Photographs and reports abounded of wildlife reclaiming urban spaces, of wildness flooding back to fill the space vacated by human beings who had taken themselves hostage in their homes. Fanciful, false and often downright foolish, such claims seldom had any scientific basis.

And yet, there was an undeniable hopefulness that underscored the reports. Could it be that by removing ourselves from the wilderness for the equivalent of a geological blink of an eye, our momentary absence from many places had forced us to look with new eyes at the scale of our footprint? And perhaps we had started imagining where animals might move when the barriers to their movements are removed. Listening to Iyer again against the backdrop of a pandemic, I found myself revisiting the results of a marine study that had done precisely this exercise one year previously. Where do we find ourselves spreading our impact across our oceans and what does this mean for sharks?

Many species are resident to a particular coral reef or a certain sea-grass bed. But many other animals, especially sharks, are wide-ranging, open ocean nomads that move outside the safe bounds of MPAs. Understanding their movement patterns is key to protecting their populations. Photo © Ryan Daly

The Global Shark Movement Project

In July 2019, Dr Nuno Quieroz from Universidade do Porto in Portugal and Professor David Sims from the Marine Biological Association Laboratory in Plymouth, United Kingdom, published a paper in the journal Nature that made media headlines worldwide. Their research formed part of the Global Shark Movement Project (GSMP), a collaborative effort to understand how sharks are moving around the seas relative to changing patterns in climate, increasing pollution levels and how humans use the oceans for shipping, fishing and mining. Its findings were decided and divisive. According to the study, there is little refuge left for pelagic sharks, those mobile predators of the open ocean, because the footprint of industrial longline shark fisheries overlaps with critical pelagic shark habitats. Concerned reports flooded out and there was some quibbling with rebuttals on the niceties of grid cell sizes and statistical calculations. However, it was undeniable that Nuno Quieroz, David Sims (who heads the GSMP) and more than 150 scientists from 26 countries who had submitted their data for the study had forced us to reckon with the widespread nature of our footprint on the ocean.

Simultaneously, their results highlighted the global scale at which we need to be working to manage our impact on the ocean and its biodiversity. In Sims’s own words for an interview with the Save Our Seas Foundation when the publication was released:

‘The only way we can answer questions about shark ecology and the impacts of fisheries on shark hotspots globally is to work collaboratively on a global scale. No single research group could hope to collect sufficient data to undertake the analyses that are needed to provide sound scientific evidence to inform shark conservation on the high seas. It’s something for which we all need to work together.’

The occupancy and mean straightness of movement for shark 7 (384 cm male) for the first and second year of its track (measured from tagging date). Data from Lea et al. 2015 https://doi.org/10.1038/srep11202. Maps created in ArcGIS, using GSHHG coastline data and ETOPO2v2 bathymetry data.

Tracking sharks from space

But how does one begin to grapple with collecting data about where sharks – and shark fisheries – are moving around the globe? For this, the scientists turned to space. Using the data collected from satellite transmitter tags placed on 1,804 individual sharks representing 23 species across the Atlantic, Pacific and Indian oceans, they mapped ocean ‘hotspots’ – areas that sharks were using frequently or where they were aggregating. To figure out the extent to which these shark hotspots overlapped with the areas worked by longline fishing vessels, the researchers needed to overlay information on where the fishing vessels were – in ocean space, that is. For this they used information beamed from ship Automatic Identification Systems (AIS). These systems transmit a ship’s position to satellites orbiting the earth and are mandatory for vessels over 300 tonnes in size that traverse international waters. Their use? To prevent ship collisions at sea. Their incidental value to conservation science? Researchers can use these ‘satellite tracks’ in the same way they use the data transmitted from shark tags.

By effectively overlaying two transparencies – one showing where sharks were moving and the other where fishing vessels were moving – David Sims and his team were able to calculate the percentage overlap of fishing with their identified shark hotspots. To his disappointment, the level of overlap was more than David had anticipated. ‘We didn’t realise the sheer scale of the overlap and fishing effort centred on shark hotspots, resulting in a near entire overlap of the tracked range of two species, the blue and shortfin mako sharks, which are commercially important and account for more than 90% of the pelagic sharks caught by longline fisheries,’ he explained.

SPOT tags are attached to animals that come to the ocean’s surface. Dolphins, seals and turtles all come to the surface to breathe, and a shark’s dorsal fin often sticks out above the water. Photo © Chelle Blais.

The art of tracking

The art of tracking is certainly nothing new; it’s as ancient as our own human histories and is a fundamental part of how we’ve always related to other animals. But it’s only since the 1960s that scientists have been tracking animals to answer ecological questions on a larger scale, and they’ve been using different kinds of tags and receivers. Acoustic tags send a signal to underwater receivers, usually set up over a set area as an ‘array’ that records a ‘ping’ each time a tagged animal swims within range. The results give scientists insight into where, when and over what distances different sharks or rays are moving. This was how Dr Chantel Elston from Rhodes University in South Africa was able to identify a potential nursery site for porcupine rays (Urogymnus asperrimus) by tracking 22 individual rays around St Joseph Atoll in Seychelles. And how Dr Lauren Peel figured out just how important D’Arros Island and the very same St Joseph Atoll are for reef manta rays (Mobula alfredi).

However, many sharks and rays range widely across the oceans and several species undertake phenomenal migrations. When the Russians launched Sputnik into space on 4 October 1957, the potential opened for a very different kind of ‘array’ to track movement patterns on earth. By employing a different kind of tag, one that uses the constellation of satellites that now orbit our planet, researchers like Dr Tristan Guttridge could work out that a great hammerhead shark (Sphyrna mokarran) he called Gaia swam from Bimini in The Bahamas to South Carolina and back, a round trip of 1,600 kilometres (994 miles). Uncovering the story of Gaia and other great hammerheads like her who call The Bahamas their home revealed that these sharks make epic journeys of up to 3,030 kilometres (1,883 miles).

Satellite tags zoom our vision of animal tracks out to the widest possible extent; they are used to follow the large-scale movements of ocean animals from whale sharks to tiger sharks and giant trevally fish to manta rays. Pop-up satellite archival tags (PSATs, or PAT tags as scientists dub them) transmit data to scientists via the Argos satellite system. The tags are attached externally (usually to the dorsal fin in the case of sharks) and there they log information about location, water depth, sea temperature and oxygen levels as the animals swim across the ocean. After a specific period, the release section of the tag is popped off or corroded, releasing the PAT tag to the sea’s surface for retrieval.

And so, the GSMP team is using satellite tagging to compile a database that holds information about the ocean-wide movement patterns of 23 shark species over more than 280,000 tracking days. Other researchers around the world deploy satellite tags to add to our growing awareness of the scale of connectedness across our oceans. Dr Ryan Daly from the Oceanographic Research Institute, for example, tracked a tiger shark called Sereia a staggering 6,500 km (4,039 miles) from Mozambique to Indonesia. The finding set the record for the longest known transoceanic journey for her species and changes the face of how scientists recommend managing sharks that clearly flout international borders drawn in faint lines on maps spanning our seas.

As the dorsal fin of a great white shark breaks the sea's surface, signals of its travels are sent to a satellite. Photo © Alessandro De Maddalena | Shutterstock

But what should we do with these data and how best can they contribute to changing policies and improving protection?

This was the question posed by a recent assessment published in Trends in Ecology and Evolution, written by Graeme Hays and a host of contributors, including Ana Sequeira, a lead researcher on the GSMP project. Satellite tracking is expensive and a necessarily more invasive research method initially than more remote methods like underwater cameras and photo identification. Nuno Quieroz and David Sims’s study reminds us that we need to be thinking about the movement patterns of sharks in relation to our own. Tangible evidence of policy shifts makes a stronger case for continued investment in research and technology that should not only astound us and challenge our thinking, but help change the trajectory of our future.

In 2001, David Sims embarked on a different kind of study using PSAT tags that ultimately showed that basking sharks (Cetorhinus Maximus) can move thousands of kilometres in mere weeks, but return faithfully to the local feeding grounds that sustained them. These landmark findings helped re-interpret what the impact of fishing could be on these populations and helped to make the basking shark one of the ocean’s most protected sharks. It is now listed on Appendix II of both the Convention on International Trade in Endangered Species (CITES) (a first for a commercially fished species) and the Convention for the Conservation of Migratory Species of Wild Animals (CMS).

Graeme Hays, Ana Sequeira and the other authors of the paper ‘Translating Marine Animal Tracking Data into Conservation Policy and Management’ unpack cases where tracking seabirds, marine mammals, fish and sharks have changed the ways we relate to them in policies, laws and protocols. But one of their most interesting suggestions speaks to a concept that undoubtedly resonated in our collective consciousness in the year 2020. The word ‘connection’ has taken on new gravity during a pandemic that saw us leaning heavily on our technological crutch to relate to everyone from family and friends to colleagues and schoolteachers. And yet it is precisely this concept – connection – that underscores so much of what we still need to achieve in conservation.

Hammerhead sharks are among the ocean’s greatest nomads and tracking the journeys they make is especially important for two Critically Endangered species: the great hammerhead and the scalloped hammerhead. Photo © Sarah Dauphinee

The researchers suggest that tracking data can change decision-making through what is called ‘the web of influence’. Open your smartphone, connect to any social networking app and you’ll see neon lines spread like veins across ocean maps to keep us connected to the unfolding stories of sharks like Sereia and Gaia. Satellite-tagging scientists increasingly share their research, often in near real-time, on their social media pages and on project apps like the Guy Harvey Research Institute’s Shark Tracker and Ocearch. The celestial array that tracks all our movements connects all of us: sharks, those of us who follow their stories and the ships that traverse the seas in search of them. The increasing transparency of these satellite tracks and the ease with which we can all connect to the different components of this story – of people and of sharks – might help us to visualise a world where we share ocean space. Perhaps this is exactly what the GSMP and projects like it are prompting us to see. It’s not our absence from the wilderness that should encourage us to reimagine our impact, but rather a continued reminder of just how we move across this planet alongside the myriad other species that call it home.

Whale sharks may cross paths with fisheries, where they risk being caught, or traverse shipping lanes, where they are in danger of being struck by a ship. Tracking the movements of these Endangered sharks helps scientists to tailor conservation strategies specific to their needs. Photo © James Lea

Where to from here?

So as much as tracking animals has been about knowing where to find resources or how to hunt food, there has always been a more ethereal element that keeps us entranced. Perhaps it lies in a bid to gauge our place on this planet as part of a matrix of life. And it is in conversation with Lauren Peel about the range of findings her tracking has yielded about manta rays that an interesting idea crops up. While it is undoubtedly important to understand how sharks and rays are moving relative to us in the ocean, it’s equally important to know how they move independently of us – to give flight to our imagination and perhaps rekindle in us a sense of awe at what we can still learn from the stories that ocean creatures have to tell.

‘Animal tracking breaks the water barrier. It gives us a unique way of connecting to ocean creatures in today’s world without necessarily getting underwater or even speaking the same language as the researcher who is trying to describe that animal’s story,’ reflects Lauren.


I pause to imagine what her words are painting, remembering the stories that satellite tracks etched onto computerised maps can tell us about the secret, but spectacular lives that sharks lead.

‘To understand where these huge animals are going takes serious technology,’ Lauren continues, her voice earnest. ‘We can’t simply chase after a manta ray; as soon as it swims away from a cleaning station, our diving fins and even our boats can’t keep up.’ With satellite tracking, she has visualised how manta rays are moving in order to manage them better, ‘to get a feel for the scale of movement that we’re looking at; to get an idea of whether small marine protected areas around key islands are sufficient or whether we need to investigate protection across the whole Amirantes Bank in Seychelles.’

There is exciting potential in what every technology offers us. Databases logging information from space that come from shark tags, from vessel monitoring systems and from AIS provide the momentum to propel us towards whichever future we choose to imagine. But momentum is not the same as direction, and if there is anything we might have learnt from 2020, it is that technology is not the end in itself. Rather, it is a means to an end. Where we go from here depends on how wisely we learn to harness its power as a tool. ‘Almost everybody I know has this sense of overdosing on information and getting dizzy living at post-human speeds,’ Pico Iyer reminds us. Perhaps this is our chance to reflect on those little digital tracks that blink back at us from our computer maps and the speed at which we race to overlap in space. If this could help us notice what our presence means and not what our absence suggests, a new direction might bring renewed hope of shared ocean space.