More than 600 Indian softshell turtles, some of them dead, were seized from the courtyard of a fish trader’s house in Naihati, North 24-Parganas, on Tuesday morning.

The trader’s son has been arrested. The Wildlife Crime Control Bureau and the forest department are trying to track down the other members of the racket.

A team of officials of the Wildlife Crime Control Bureau and the North 24-Parganas forest division raided the house after they received a tip off.

On searching the house, the team found the turtles crammed inside plastic crates that were stacked up and covered in plastic sheets, a forest department official said.

“The rescued turtles were Indian softshell turtles that are protected under Schedule I of the Wildlife Protection Act,” Agni Mitra, deputy regional director of the Wildlife Crime Control Bureau, an agency under the ministry of environment and forests, said. “The killing, hunting or selling turtles is illegal.”

Mitra was monitoring the raid.

The turtles are of various sizes. Several had died because of improper transportation, a forest department official said.

The arrested man has told forest officials that the turtles were headed to markets in Barasat and Bongaon, the official claimed.

“The Indian softshell turtle is in high demand for its meat,” another official said.

Mitra said the turtles had been smuggled in from Uttar Pradesh. “The turtles were put on a mini-van which drove to Naihati.”

The turtles that have survived have been kept in the forest department’s Barasat office.

“We will monitor their health for a few days before releasing them,” the forest official said.

The International Union for Conservation of Nature (IUCN) lists Indian softshell turtle as “vulnerable” in its Red List of threatened species.