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")