Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Envisat radar surveillance protects endangered prehistoric fish

18.11.2005


A satellite surveillance zone within the southern Indian Ocean is helping protect the endangered Patagonian toothfish from pirate fishing vessels.



Perched between Africa, India, Australia and Antarctica, the windswept French territory of the Kerguelen Islands is one of the remotest places on Earth. Even so, fishing vessels are lured there by the prospect of catching one valuable species found in its surrounding waters – the Patagonian toothfish, also known as Chilean sea bass, or else ’white gold’ for the high prices it commands on the black market.

However a radar satellite surveillance system based on Envisat and Radarsat-1 imagery has cut the number of illegal fishing incursions in the vicinity of Kerguelen Island by nine-tenths. Run for the benefit of the French maritime authorities by the firm CLS (Collecte, Localisation Satellites), a subsidiary of the French space agency CNES, the system is up and running at a time when overfishing has left the 40-million-year-old Patagonian toothfish species on the verge of extinction.


Also found off South America, the toothfish has evolved anti-freeze components in its blood, making it one of a small number of species to colonise the sub-Antarctic waters of the Southern Ocean, playing an important role in the ecosystem there, providing sustenance to whales and seals.

Toothfish dwell in deep waters on the edge of coastal shelves and sea mounts. Individual toothfish can live for 40 years but take a decade to reach adulthood: their slow-maturing character makes them especially vulnerable to overfishing.

As toothfish numbers have crashed in heavily fished waters off Chile and Argentina, fishermen are increasingly drawn to Southern Ocean fisheries. However strict quotas have been set to preserve numbers. France maintains an economic exclusion zone (EEZ) extending 360 kilometres offshore from Kerguelen Island, along with its nearby Crozet and St-Paul Amsterdam territories.

Only French-owned ships are authorised to fish in the combined French Southern and Antarctic Territories EEZ, mostly working out of the French territory of Réunion Island, around 3000 kilometres west of Kerguelen. However this region has proved increasingly popular with pirate vessels intent on defying the law.

Réunion is the second largest producer of Patagonian toothfish behind Chile. So the toothfish is very important to it, earning in the region of 40 to 60 million euros for its economy annually. However in recent years the toothfish has fallen prey to illegal uncontrolled fishing. It is estimated that pirate vessels have been fishing up to 26 000 tonnes a year – nearly four times the legal quota.

In the last few years authorities have introduced measures to limit illegal fishing in the EEZ, defend France’s economic interests, protect ecosystems and stamp French sovereignty on their territorial waters. A surveillance system using French naval vessels has achieved some success, however the number of vessels fishing illegally continued to rise, and they proved adept at slipping through the surveillance net.

The EEZ totals nearby one million square kilometres of ocean – too great an area for naval vessels to police effectively. So the French maritime authority turned to satellite surveillance – employing ESA’s Envisat satellite in conjunction with Canada’s Radarsat-1.

The radar sensors aboard these spacecraft can monitor the region during both day and night and in all weathers, including cloudy conditions. The metal corners of ships make good radar reflectors, sending back distinctive signal echoes. Using the two spacecraft together means updated images become available daily, downlinked to a dedicated ground station located on Kerguelen Island.

"Kergulen is a remote and inaccessible place, but it has the advantage of being at the centre of the area we want to survey," explained Philippe Schwab, Technical director of CLS. "New images are received in real time, then automatically processed to discriminate radar echoes from vessels in the zone. Each vessel is then sent with its position via a satellite link to the French authorities on Réunion, where they are analysed to identify legal and illegal vessels.

"Authorised vessels are mandated to have an Argos satellite transmitter aboard, so they can be located and identified. Vessel positions are sent to the French authorities by CLS, the Argos system operator. Argos positions are then matched with radar echoes to discriminate illegal vessels, whose locations are then sent for action to French Navy patrol boats."

The system has been operational since February 2004. It had an early success on 25 June 2004 when French Navy patrol boat Albatross intercepted the Apache, a fishing vessel sailing under the Honduran flag. First identified southeast of Kerguelen Island, the operations centre on Reunion tracked the vessel for three days. The patrol boat fired a warning shot across its bow then boarded it to seize an illegal catch of 60 tonnes of Patagonian toothfish.

"Usually the system is more dissuasive than repressive," Schwab concluded. "Today, illegal fishing has almost disappeared. It seems that the unscrupulous fishermen have understood the efficiency of the system."

Satellites for ship detection

Satellite radar sensors detect ships well because their metal surfaces and sharp angles have a high signal return, in contrast to that of the surrounding water.

Envisat ASAR imagery is therefore being utilised for ship detection in a growing number of activities worldwide, including the protection of Icelandic fisheries through the Improving fisheries Monitoring through integrating Passive and Active Satellite-based Technologies (IMPAST) project run by the European Commission’s Joint Research Centre (EC-JRC).

Mariangela D’Acunto | alfa

More articles from Ecology, The Environment and Conservation:

nachricht Minimized water consumption in CSP plants - EU project MinWaterCSP is making good progress
05.12.2017 | Steinbeis-Europa-Zentrum

nachricht Jena Experiment: Loss of species destroys ecosystems
28.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

Im Focus: A transistor of graphene nanoribbons

Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."

Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

Making fuel out of thick air

08.12.2017 | Life Sciences

Rules for superconductivity mirrored in 'excitonic insulator'

08.12.2017 | Information Technology

Smartphone case offers blood glucose monitoring on the go

08.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>