Efforts on to revive Galapagos tortoises once thought extinct

Updated 18 June 2013
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Efforts on to revive Galapagos tortoises once thought extinct

Scientists will try to revive two species of giant Galapagos tortoises thought to have been extinct by breeding genetic relatives in captivity, experts leading the effort said.
The Galapagos Islands, located 1,000 kilometers (600 miles) off Ecuador’s Pacific coast, are famed for the large number of species that have developed there in isolation.
New research techniques have revealed that at Wolf volcano on Isabela Island, 17 hybrid giant tortoises have been found with genes from the extinct Pinta Island tortoise, and about 280 hybrids have been found with genes from the extinct Floreana Island tortoise.
Among those with Pinta genes, at least one pair has 80 percent of the original species’ genes, while among the Floreana hybrids, many have up to 90 percent of the original species genes.
“That gives us the possibility, literally, of bringing back these species which at the moment are considered extinct,” Galapagos National Park applied sciences chief Washington Tapia told AFP.
Giant tortoises have life spans of up to 180 years, growing to 1.8 meters (five feet nine inches) long and nearly 400 kilograms (880 pounds) in weight.
Last year the body of “Lonesome George,” a giant Galapagos tortoise once believed to be the last of its kind, was sent to New York after its death to be embalmed and then returned home.
A rare Pinta Island giant tortoise discovered in 1971, George was estimated to be a century old when he died June 24, 2012. At the time, he was believed to be the last of his kind.
The Floreana Island tortoise was widely thought to have been extinct for more than 100 years. One of their last sightings was by British naturalist Charles Darwin when he visited the Galapagos in 1835.
Darwin studied the tortoises, which evolved in isolation, as he developed his theory of natural selection.
Now Tapia’s team is eyeing something of reverse natural selection: bringing back to life animals technically considered to have died out.
He said that experts will soon start trying to get pairs in captivity to produce offspring close to their genetic origin. But due to the lengthy lifespan of the animals, Tapia said that he will not live to see the results: true to the slow pace tortoises are famous for, it should take about 120 years to get all the data in.
The female tortoises reach sexual maturity at around 20-25 years, and males at around 25-30. Tapia said that mating a female and male with 80-90 percent Floreana genes should produce offspring with about 95 percent of the genes of the original species.
With the Pintas, “there is a chance, albeit remote, that we could end up with a male being produced with only original-species genes,” Tapia said.
For now, the future of the Floreana lies with about 92 animals born in captivity since 2012. More testing has to be done to determine which have the greatest original-species genetic content so that those males and females can be bred.
Tapia said that one of the main goals is for the tortoises to be released back into their natural habitats as soon as possible, even as hybrids, so that they can help bring the ecosystems of the islands back into balance after they were disturbed by imported species, such as goats.

The Wolf hybrids have a salty story of their own: park officials believe the tortoises were taken to Isabela Island in the 17th and 18th century by pirates who picked them up to eat, but then decided they were no longer needed as a source of meat and tossed them overboard.


Greek researchers enlist EU satellite against Aegean sea litter

Greek university students gently deposits a wall-sized PVC frame on the surface before divers moor them at sea at a beach in the island of Lesbos on April 18, 2019. (AFP)
Updated 22 April 2019
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Greek researchers enlist EU satellite against Aegean sea litter

  • “All the targets were carried into the sea, the satellites passed by and we’re ready to fill out the first report”
  • Satellite data is provided free from the European Space Agency (ESA) and hours after the overpass targets should be detected from the Sentinel-2 satellite

LESBOS ISLAND, Greece: Knee-deep in water on a picture-postcard Lesbos island beach, a team of Greek university students gently deposits a wall-sized PVC frame on the surface before divers moor it at sea.
Holding in plastic bags and bottles, four of the 5 meter-by-5-meter (16 foot-by-16-foot) frames are part of an experiment to determine if seaborne litter can be detected with EU satellites and drones.
“This was the first big day,” says project supervisor Konstantinos Topuzelis, an assistant professor at the University of the Aegean department of Marine Sciences, said of the scene from last week.
“All the targets were carried into the sea, the satellites passed by and we’re ready to fill out the first report.”
The results of the experiment — “Satellite Testing and Drone Mapping for Marine Plastics on the Aegean Sea” — by the university’s Marine Remote Sensing Group will be presented at a European Space Agency symposium in Milan in May.
“Marine litter is a global problem that affects all the oceans of the world,” Topouzelis told AFP.
Millions of tons of plastic end up in the oceans, affecting marine wildlife all along the food chain.
“Modern techniques are necessary to detect and quantify marine plastics in seawater,” Topouzelis added, noting that space agencies have already been looking into how drones and satellites can help with the clean-up.
“The main advantage is that we are using existing tools,” which brings down costs and makes it easier to scale up, says Dimitris Papageorgiou, one of the 60 undergraduate and postgraduate students who worked on the experiment.
To prepare, the team gathered some 2,000 plastic bottles and lashed them to the frames. Other targets were crafted with plastic bags, as these are even harder to spot in the water and usually constitute the deadliest threat to Aegean marine life such as dolphins, turtles and seals.
In 2018, a first phase in the experiment was able to detect large targets of around 100 square meters from space.
This year’s experiment uses targets a quarter that size to test the smallest detectable area under various weather conditions.
“It was a crazy idea,” laughs Topouzelis.
“We knew that the European satellite system passes at regular intervals with a spatial resolution of 10 meters.”
In theory, then, the satellites should be able to detect the floating rafts of plastic the team pushed out to sea.
The University of the Aegean is working on the project with Universidad de Cadiz in Spain, CNR-Ismar in Italy and UK environmental consultants Argans Ltd.
Satellite data is provided free from the European Space Agency (ESA) and hours after the overpass targets should be detected from the Sentinel-2 satellite.
The project acts as a calibration and validation exercise on the detection capabilities of the satellites.
But even if relatively small patches of plastic garbage can be spotted from orbiting satellites, the problem of how to remove it from the sea remains.
Last year, a giant floating barrier five years in the making was launched off the coast of San Francisco, as part of a $20-million project to clean up a swirling island of rubbish between California and Hawaii.
But the slow speed of the solar-powered barrier prevents it from holding onto the plastic after it scoops it up.