In a shaded stream in the middle of Berlin's rambling Tiergarten park, fisherman Klaus Hidde lowered himself into the water recently. Several children stood on a platform above him and watched him wade in, wearing high rubber overalls. Hidde pulled a netted trap out of the water and shook it in the air.
"There's too few," Hidde says, shaking his head.
Hidde and his son are the only people licensed to catch thousands of Louisiana crawfish that have invaded the waters of two parks in Berlin. The goal is to solve the problem by selling the catch to chefs and businesses. But on this day, there are a scant 100 crawfish between three nets.
"They're not even a hundredth of a percent" of the solution to the problem, Hidde says, as he shakes the dark red crustaceans into a black bin.
This is the third year Louisiana crawfish have been seen in Berlin. City wildlife officer Derk Ehlert says when crawfish first appeared, the city released eels into the waterways, hoping they'd catch the crawfish and eat them. But then the next year, there were still 3,000 crawfish in the parks. This year there are 10 times as many and they seem to be spreading. At one point, hundreds of crawfish clambered out of the lake and ambled along the Tiergarten's shaded paths.
"It's normal for them but [ab]normal for the people in Germany," Ehlert says.
Crawfish are not entirely foreign to Germany. But the Louisiana crawfish, Procambarus clarkia, crowd out the native Astacus astacus European variety and carry a disease that kills them, Ehlert says.
"The home animals and plants must be saved," he says.
Louisiana crawfish have become a familiar problem elsewhere in the world, too: They have scarfed down freshwater fish and other animals in Egypt, Kenya and South Africa. They turned up in Michigan. And a species of Washington State crawfish threatens trout in Scotland. There, authorities caught and killed the crawfish, to avoid creating a market for them.
Berlin's experiment with eating the invasive crawfish is still a work in progress. To the west of the Tiergarten, in the Spandau borough, Olaf Pelz cracked the shell of one of Hidde's red crawfish in his restaurant, called Fisch Frank. Across town, the trendy Markthalle Neun food market hosted a Louisiana-style crab boil in mid-July, cooking the crawfish in a piquant broth and serving them on trays with corn and potatoes. But Pelz said most of his customers are older and prefer a simple recipe.
"When we serve it here we make it with salad and bread and typical sauce," he says. He puts dollops of mayonnaise and cocktail sauce on the plate, and tops the crawfish with a thin slice of lemon.
Despite his efforts, customers are skeptical. Erika Klugert rises from her outdoor table to watch Pelz uncover the soft tail meat of the crawfish.
"This food requires too much work," Klugert says. She says she just ordered shrimp from Pelz and ate it. And it was much easier. "Without a shell, but it was delicious."
Hidde, the fisherman, notes another challenge: matching supply with demand. When he caught thousands of crawfish earlier this year, he says he struggled to find buyers. In late July he got an order for about 100 pounds of crawfish, but he could only find a few of the creatures in the one stream he checked in the Tiergarten. He guessed the rest were hiding from a Berlin heat wave.
"It gets on your nerves," he says of the uncertainties he faces on the job. "I raise expectations with people for a lot of crawfish, and I can't always fulfill them." He says he has about 25 traps strung across the Tiergarten and Britzer Garten, and hopes some of the others might help make up the order.
He has also bought a few more days of flexibility by using a swimming pool in his backyard as a holding tank.
Hidde acknowledges it may be impossible to clear all the invasive crawfish out of the waters of the two parks he has targeted. He finds five Louisiana crawfish for every Berlin crustacean, he says.
"There are so many that the effect is very small," he said. "It's like a hamster race."
Still, he says, he hopes his culinary fishing mission might at least hold the line and protect the rest of Germany's waters.
RACHEL MARTIN, HOST:
OK. We're switching gears now over to Berlin, where there is a strange invasion of Louisiana crayfish. The problem reportedly stems from some Berlin residents who bought the fish as pets, only later to dump them in public waters. Here's reporter Daniella Cheslow.
(SOUNDBITE OF WATER SPLASHING)
DANIELLA CHESLOW, BYLINE: Fisherman Klaus Hidde eases into a stream in the Tiergarten, a rambling oasis of trees and grass in the middle of Berlin. His rubber overalls keep him dry as he pulls a trap for crayfish up above the surface of the water and shakes it.
KLAUS HIDDE: (Speaking German).
CHESLOW: He guesses he caught about 30 creatures in each of three netted traps.
UNIDENTIFIED CHILD: (Speaking German).
CHESLOW: Kids watch as Hidde works. He and his son are the only fishermen with a license to catch the animals. He sells them to local chefs and businesses. Hidde says the challenge is matching supply with demand. He's got an order for 50 kilograms - just over a hundred pounds of crayfish. But he thinks the animals are hiding from the heat.
Do you have 50 kilos here?
HIDDE: No. (Speaking German).
CHESLOW: He hopes to make up the order from his other two dozen traps across the Tiergarten and another park. He uses a swimming pool in his backyard as a holding tank. The idea for catching and serving the crayfish, also known as crawfish, came from the Berlin government as a way of controlling the invasive species. Derk Ehlert is with the city's department of the environment.
DERK EHLERT: 2016 was the first time when people ring up and told us about the crawfish in Tiergarten.
CHESLOW: That first year, the city released eels into the waterway, hoping they'd catch the crayfish. But then in 2017, there were still 3,000 in the parks. And this year, there are 10 times as many, and they seem to be spreading.
EHLERT: The crawfish come out of the lake and runs out of the water through - over the ways.
CHESLOW: Ehlert says the Louisiana crayfish crowds out the endemic European variety and carries a disease that kills them.
EHLERT: The home animals and plants must be saved because they grow up in this country more than thousand years.
(SOUNDBITE OF CRAWFISH SHELL CRACKING)
CHESLOW: Olaf Pelz cracks the shell of one of Hidde's red crayfish in his restaurant in western Berlin. In mid-July, there was a Louisiana-style crayfish boil in the trendy food market in the city. But Pelz keeps his recipe simple.
OLAF PELZ: When we serve it here, we make it with salad and bread and typical sauce.
CHESLOW: He says it takes a strong hand to break off the shell and reveal soft tail meat underneath. While we talk, customer Erika Klugert takes a look.
ERIKA KLUGERT: (Speaking German).
CHESLOW: She says, "this food is too much work." She just ate shrimp that was served with no shell. It was easy, and it was delicious.
For NPR News, I'm Daniella Cheslow in Berlin.
(SOUNDBITE OF EEVEE'S "HOLD UP") Transcript provided by NPR, Copyright NPR.