It would be easy to overlook the marbled crayfish. If it is not already there, it will be coming to a pond or river near you soon. The all-female freshwater crustacean has become a focus of fascination for scientists in recent years due to its unique ability to clone itself and quickly adapt to new environments, as well as the fact that it has spread.
A biology student bought a bag of crayfish from American traders at a pet fair in Germany in 1995 and used it as his own. After becoming a burden to their new owner due to their rapid rate of reproduction, he distributed them to friends who dumped them in rivers, lakes and toilets from where they spread rapidly, throughout Germany, much of mainland Europe and most profusely, the island of Madagascar.
When he first came across the creatures, called marmorkrebs, he was astonished by their ability to reproduce from a single cell, like cancer tumours.
The swamps of Florida have been the site of a search for marbled crayfish. Noam Lyko is photographed.
He says that all marbled crayfish have the same genome. They adapt to different environments in a hurry, which makes them scientifically remarkable and similar to a tumours, which also adapt to its environment.
The genome study led to the discovery that all of the marbled crayfish are descended from a single female. They reproduce without sex. The all-female crustaceans were given a species name in 2015.
Q&A show.
Invasive plant and animal species can disrupt the natural balance of the environment and cause their own populations to explode. Rapid growth, fast reproduction and high resilience are some of the common traits of non-native species.
In South Georgia in the Atlantic ocean, the accidental introduction of rodents by whalers devastated bird populations for 250 years and required a huge mouse and rat eradication programme to protect native wildlife.
Why are they a problem?
Invasive species can cause large-scale economic and environmental damage if they are introduced into an area. Japanese knotweed damages building foundations and flood defences in the UK, costing hundreds of millions of dollars a year.
The European wild boar, the North American grey squirrel, and the South American water hyacinth are some of the highly problematic invaders.
How do they spread?
Large-scale redistributions of plants and animals around the world have caused local extinctions of native organisms. A recent study warned that the spread of non-native plant and animal species around the globe could lead to a loss of biodiversity.
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In the course of his research, he recalls driving to a lake with his students. He says they waited until it got dark, then suddenly they emerged in their hundreds and thousands. We put them in buckets with a hand net. It was very exciting. We started experimenting with eating them and found them to be quite tasty.
The more we eat, the better.
The authorities in Germany have adopted a strict approach to the marbled crayfish.
The environment department of the Berlin senate asked Klaus Hidde, a retired bank clerk turned hobby fisher, to set traps for the crayfish. The crayfish are in danger of killing off native species and can also carry a disease that wiped out the European market 150 years ago.
Four years ago, Hidde was contracted by the department to catch armies of red swamp crayfish that had broken out of ponds in parks, including the central Tiergarten, after heavy rain. I caught 42,000 of them in one year. He says he was seen as a bit of a saviour even if he said it himself. He received a top-up of 7 from the senate. Berlin restaurants served the crustaceans as a novel, "Berlin lobster".
In Berlin's Tiergarten park, a red swamp crayfish was taken out of the water. The picture is by Carsten Koall.
Hidde believes that officials are reluctant of creating demand for cloned animals, which could promote their breeding and make the problem worse. He admits that he has yet to develop a taste for the meat, and that he may give up unless they are prepared to make it worth his time. I like to eat gambas when I go to Spain.
The co-founder of Holycrab! hopes the marbled crayfish will convince Germans to look for sustainable alternatives to meat. The company is teaming up with top Berlin chefs to make Chinese mitten crabs, Egyptian geese, and other non-native species into gourmet delicacies. They are experimenting with turning the animal's high-value protein into rich fish stew and stocks, and already sold the meat tails of the animal on bread rolls.
Berliners can take on that role as the crayfish have no natural predator. Rather than giving up meat, we should eat more of it.
We need to learn to live with it.
Ranja Adriantsoa, a freshwater ecology student, first came across the marbled crayfish in Madagascar. She delicately lifts one out of a tank in her lab, which is 12 cm from the tip of its tail. She points to the animal's large appendages on its tail, which can hold between 200 and 700 eggs. One female can create a population of millions of genetically identical females if she reproduces four times a year.
You would not want to import these but the attitude is how to live with them.
Ranja Adriantsoa is a biologist.
The department of Invasive species control at the University of Antananarivo in the Madagascan capital was focused on stopping the spread of the marbled crayfish, which are highly destructive, eating fish larvae and destroying the nation.
Adriantsoa says that the perception has changed over time. The fact that they are here and established makes it easier to live with them.
Adriantsoa and a team of scientists launched the Perfect Invader to look at the impact of the marbled crayfish on human health. The crayfish can be an important source of cheap, high-quality protein for the poor of the world, where 42% of children are affected by stunted growth.
The red swamp fish was popular in Berlin. The researchers are looking at the food potential for the marbled crayfish. Fabrizio Bensch is pictured.
The research looked at the potential for the marbled crayfish to help tackle the transmission of schistosomiasis, which affects an estimated 290 million people worldwide. The hypothesis is that the freshwater snails that host the parasites that cause the acute and chronic disease are preyed on by the crayfish.
In Germany, the largest research institute in the country, the Helmholtz Association, is working with a company called Lyko to turn the shells of the marbled crayfish into plastic. He says that the first ever crayfish drinking straws will be this month.
Jones says that she and other scientists have learned to see the big picture.
While we need to understand the negative impact of the marbled crayfish in Madagascar, we also need to understand that people have to live with it.
She wanted to stress that all measures should be taken to stop the marbled crayfish from coming anywhere else. The animals are not allowed in the EU and UK.
Jones says that they will be in the UK eventually, and that they were in Poland the last time he looked. The zebra mussel, cane toad, and grey squirrel are some of the famous invaders that have gone down in history.
If you are reading about this for the first time, you will hear a lot more about the marbled crayfish.
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