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 International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>