The world’s oceans cover more than 350 million square kilometres of the earth’s surface. In their most remote areas lurk an unknown number of ‘dark vessels’ – fishing boats that have turned off their transponders so that they can carry out illegal fishing undetected.

This practice is a major threat to the marine environment. Illegal fisheries deplete fish stocks, drastically affecting local economies and marine habitats. Unregulated boats often use illegal long-line fishing techniques which endanger dolphins, seabirds and other animals that become entangled in the lines.

Authorities have struggled to curb illegal fishing because it is difficult to detect boats operating without permission. To meet this challenge, researchers in the ERC-funded OCEAN SENTINEL project have developed the world’s first ocean-surveillance system by enlisting the help of an unlikely ally: the albatross.

When albatrosses search for food, they embark on foraging trips that can last up to 15 days and cover thousands of miles. By successfully developing a data-logger small enough to be attached to the birds, the project team was able to turn these journeys into illegal fishing patrols. While the albatrosses foraged for food, their 10-cm long data-loggers simultaneously scanned the ocean, using radar detection to identify boats and transmit their location back to analysts in real-time.

‘A system using animals as surveillance at sea has never been created before but we have been able to use the birds to locate and instantly inform authorities about the location of vessels, and to distinguish between legal and illegal fishing boats,’ says principal investigator Henri Weimerskirch of the French National Centre for Scientific Research (CNRS).

‘We were proud we could work with the albatross because they are the family of birds most threatened by illegal fishing,’ he adds. The curious birds can become caught in illegal lines when they swoop down to investigate the fishing boats and their baits.

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Surveillance for statistics

During the project, Weimerskirch and his colleagues visited albatross breeding grounds on French island territories in the Southern Indian Ocean. Here, they attached data-loggers to 169 albatrosses to track the birds as they flew out to sea to find food.

As the albatross foraged, they recorded radar blips from 353 vessels. However, only 253 of the boats were broadcasting their identity, position and speed to the relevant authority, leading the team to conclude that the remaining 100 ships (37 %) were a mix of illegal and unreported vessels.

‘This is the first time the extent of illegal and unreported fisheries has been estimated by an independent method,’ says Weimerskirch. ‘This information is essential for the management of marine resources and the technology we developed is already being used by the authorities to improve management in these vast, difficult to manage regions.’

An army of animals

The project’s success has encouraged other countries, including New Zealand and South Georgia – a UK territory – to use OCEAN SENTINEL data-loggers to spot illegal fishing in their own waters. South Africa and Hawaii are also considering deploying the technology in the near future.

Researchers are also working to adapt the data-logger so that it can be attached to other animals, such as sea turtles, which are also under threat from illegal long-line fishing.

As animals are turned into undercover surveillance systems designed to spot illegal boats, they are equipping humans with the knowledge they need to combat this problem effectively. ‘I hope our technology, alongside other efforts, spells the beginning of the end for these illegal vessels,’ concludes Weimerskirch.

Bio

Henri Weimerskirch is Director of Research at the French National Centre for Scientific Research (CNRS). He works on the impact of climate change and human activities on marine ecosystems, using seabirds and marine mammals as indicators of these changes. He pioneered the use of bio-logging to study the foraging ecology of seabirds at sea.

This article was first published in the European Commission Research and Innovation Info centre