How are snakes said to help catch crabs in Darmstadt |

They multiply rapidly, transmit crayfish plague and eat offspring: thousands of swamp crabs threaten the biological balance in a lake in Darmstadt. Now, of all things, snakes are supposed to support the hunters in their search for the unwanted guest.

Oh Geritz

They are small, bright red, sometimes gray-green, and they taste very good. However, the thousands of marsh crabs in the Prinz von Hessen pit, a bathing lake east of Darmstadt, are a problem for the local fishing club. Because the species, originally from North America, puts native species at risk.

“The swamp crab visualizes its environment,” explains Nils Boehmer, Fishing Club water monitor and himself a trained biologist. “It eats plants, fish, and amphibians.” It also transmits lobster plague that does not harm itself but kills native species such as the noble lobster. The entire food web is crumbling.

Aal should help – if everyone agrees

In addition to trapping, an animal assistant is now used to eradicate the swamp crabs population: the European eel. “Eels eat crabs,” Bohmer explains. “They come to breeding caves, where female animals carry their offspring on their stomachs.”

The method is not new, but it is rarely used. Some bureaucratic obstacles must be removed. Since eels are not allowed to be placed in stagnant water, a special permit is required, explains Patrick Heinz of the High Authority for Fisheries in Darmstadt Regional Council.

In addition, all relevant authorities must agree,” Haynes says. “After all, this is vital manipulation.” The Environment Agency and the City Green Space Agency of Darmstadt participate here. Only when they also agree to agree can they start the campaign.

He helped Offenbach

Examples from the past show that it can work. A few years ago, eels were placed in the Schultheisweiher Pond in Offenbach to eradicate swamp locusts there. “Inventory can be reduced significantly at that time,” Haynes says. However, the population density at that time was not nearly as high as it is now in Prinz von Hessen crater.

Snakes intended for storage have a lifespan of about three to four years and a length of about 20 cm. These are small snakes that come from wild catch and cannot be bred. The European eel breeds in the Sargasso Sea in the eastern United States. To do this, it migrates thousands of kilometers across the Atlantic Ocean when it is in its sexual maturity.

When the eels in Lake Darmstadt have reached a certain size and have already eaten a few crabs, they are caught again and released into the Rhine and Main. The eel is an endangered species, and last but not least, this summer’s drought and low water levels have hit it hard.

hit the list

In addition to the use of eel, the catch of swamp crabs will also be increased. About 50 additional traps were purchased, and many members of the association received special training in cancer biology and how to deal with it. Even when catching crabs, animal protection regulations must be observed.

To date, about 3,000 crabs are taken out of the lake each year. “They are especially consumed,” Bomer says. In Odenwald, swamp crawfish caught as part of a scientific study were once given to restaurants for free. “I was very welcome.”

American red swamp crab

It is not known how Procambarus clarkii, its scientific name, got into the Prinz von Hessen mine. According to a study, it was first discovered in Hesse in 2005 at the Mönchwaldsee near the airport. Patrick Hines of the regional council thinks he may have been put out of business. Marsh crabs are very popular among aquarists. “Perhaps someone wanted to get rid of their crab.”

It is expected to start in the spring

To start special control measures, it was planned to breed 800 baby eels. Haynes explains that spring is the best time to buy them. By then, he hopes, all permits will be ready. “I think we’ll start that in March and April next year.”

Boehmer, the Water Watcher, doesn’t think swamp crab will ever be eliminated. Even with extensive hunting, the stock has only been cut in half so far. It is now hoped that the use of snakes will reduce the number of cancers.

No danger to swimmers

“We’ll probably have to live with swamp cancer,” Bohmer says. “But we have to try to keep the stock to a minimum with all the available measures.” This also includes storing the mini zander. Domestic predatory fish such as pike and perch also hunt swamp crabs.

By the way, bathers do not have to worry about swamp crab. “The most that can happen is you step on someone near the shore,” Bohmer says softly. But this is somewhat unlikely. “Marsh crab is basically nocturnal.”

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