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Giant hammerhead worms from Asia have invaded French gardens

Giant tropical worms from Asia have been conducting a stealthy takeover of French gardens, putting local wildlife at risk, a new scientific study has revealed.

Giant hammerhead worms from Asia have invaded French gardens
Hammerhead worm. Photo: നവനീത് കൃഷ്ണന്‍ എസ്/Wikicommons
The creatures in question are brightly coloured, muscular giant hammerhead flatworms — so-called because of their hammer shaped head. 
 
Usually found in the tropical climates of Asia, the invaders, which can reach up to a sizeable 40 centimetres in length, have somehow wormed their way into the ecosystems of French gardens. 
 
But this isn't a recent phenomenon.
 
In fact, they've been at it for 20 years but have managed to carry out their invasion almost unnoticed. 
 
That is until amateur naturalist Pierre Gros photographed the unidentified worm in 2013 and sent it on to scientists. It eventually made its way to Professor Jean-Lou Justine, a zoologist at the French National Museum of Natural History.
 
“Blue” hammerhead worm found in Mayotte. Photo: Laurent Charles
 
“This photograph was sent from email to email to email and finally it came to me,” Justine told The Independent this week.
 
“I looked at it and said 'Well, this is not possible – we don’t have this kind of animal in France'.”
 
Justine then decided to investigate the species and over four years has amassed a collection of recorded sightings in France, as well as tropical French territories including Guadeloupe, Martinique and French Guiana, dating back to 1999. 
 
A hammerhead worm killing an earthworm. Photo: Pierre Gros
 
This led the professor and his team to draw the conclusion that hammerhead worms, which eat earthworms and other invertebrate prey and pose a threat to the ecological processes in general, are present almost everywhere in metropolitan France. 
 
The study also showed that two of the flatworm species found — one black, spotted in France, and one a blue colour, found on the island of Mayotte, a French territory in the Indian Ocean — are probably newly discovered. 
 
However what he still doesn't understand is how the creatures managed to become so prolific without the general population or the scientific community at large noticing. 
 
“I am still amazed – I don’t understand how this is possible in a developed country,” he said.
 
A species of hammerhead flatworm now discovered to be living in France. Photo: Pierre Gros
 
So, how did they get here?
 
Well, it seems most of the Asian worms currently living in France are likely to have originated from populations transported over in tropical plants.
 
And while a system has now been put in place to control their movements between countries — the UK also has its own population of hammerhead worms — they are an incredibly robust species. 
 
In fact when bits of them are amputated, they can regrow into complete worms and in one known case, a flatworm sent into space grew a second head after its tail was cut off.
 
They can also reproduce asexually and produce chemicals that make them taste unpleasant, making them unappealing to predators. 

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SCIENCE

What you need to know about the hundreds of dead dolphins washing up on French beaches

Since the beginning of the year alone, a record number of up just over 1,000 dolphins have washed up on France's Atlantic coast. So what's going on?

What you need to know about the hundreds of dead dolphins washing up on French beaches
Illustration photo: AFP
What's the story?
 
Since the start of 2019, around 1,080 have washed up on beaches along France's Atlantic coast. 
 
“We've had around 1,200 small cetaceans along the coast” of the Bay of Biscay, of which more than 90 percent were common dolphins, biologist Olivier Van Canneyt told AFP.
 
The observatory he works for said the number of dead dolphins had set a record each year since 2017, and warned that the species could be wiped out in the area.
   
“There were two peaks in mid-February and mid-March linked to currents that are stronger at that time owing to low-pressure conditions,” noted Van Canneyt, a specialist in sea mammals and birds.
 
Illustration photo: AFP
   
The observatory said that around 85 perecent of the dolphin carcasses that could be examined bore traces of accidental capture, while noting that almost three times as many dead dolphins had likely not even reached the coast.
   
Dolphins and porpoises can be caught in fishing nets and suffocated when they hunt for sea bass and whiting at the same time as fishing fleets, especially during winter months in the region.
   
The number of dolphins that wash up on the coast has increased this year despite efforts by the observatory to warn the mammals of a human presence by using acoustic “pingers”.
 
Environment Minister Francois de Rugy said in March that he would unveil a plan to limit such deaths “by the end of the year”.
 
The dolphins have been washing up on the stretch of Atlantic coast running all the way from southern Brittany to the Spanish border with large numbers of carcasses found in the departments of Vendée and in the Charentes Maritimes. 
 
Scientists say these numbers are only the tip of the iceberg as many when dolphins die, many just sink to the bottom of the ocean or are washed out to sea rather than ending up on the beaches.
 
These deaths could also threaten the dolphin populations in the years to come, researchers say.
 
 
 
 
 
Why is this happening?
 
Although hundreds of dead dolphins wash up on French beaches every year, this is a record number so early on in the year. 
 
Most of the dead dolphins found bear injury marks which researchers say are caused by big fishing boats and the large fishing nets they use. 
 
“Among the carcasses found, 93 percent show signs that they have been captured by fishing vessels and their equipment such as mutilations, amputations and fractured jaws,” according to the French environmental charity France Nature Environnement (FNE). 
 
The dolphins get caught in the vast nets used to catch fish like hake and sea bass, which the dolphins like to eat. Some of these nets are fixed in the sea bed and when dolphins get stuck in them, they can't come up for air to breathe and they suffocate. 
 
Trawlers are also a problem as they drag large fishing nets behind them which dolphins also get caught in and suffer injuries and die. When they get stuck, dolphins panic, and the stress can also kill them.
 
 
 
 
 
Is there a solution?
 
An obvious solution would be to reduce the number of large fishing vessels.
 
Environmental organisations want the number of big trawlers and other large fishing boats – which belong mainly to French and Spanish fleets – allowed to fish in those waters to be cut immediately. They are calling for a better coordination between the French and Spanish governments to find a solution to the problem. 
 
They also want observers to be allowed to board these vessels to control the fishing practices, but in practice, they say this isn't happening as the boats are reticent to do so.
 
Other solutions include putting acoustic 'repellents' on boats to keep the dolphins away. These are called 'pingers' and this year, for the first time all the large-scale French pelagic trawlers, which drag a net called the trawl at the stern of the vessel until the net is full, were equipped with some.
 
But given the record numbers of dolphin deaths this year already, the pingers seem to have little effect. 
 
FNE has pointed out that one of the problems could be that the pingers are not attached to the large nets on the sea beds, where many dolphins get caught.
 
by Emilie King
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