Diamondback terrapin turtles, which harvesters used to snap up as the main ingredient for soup, will be banned by the state for capture for food, officials said.

Diamondback terrapins, which occupy waters in and around the Long Island Sound, Peconic and South Shore bays, now can be harvested in unlimited amounts. Trappers need only purchase a license for $10 to harvest “as many turtles as they can,” according to state documents seeking to close the loophole.

The state Department of Environmental Conservation, citing a decline in the turtle population, plans to end legal commercial harvest of the terrapins, beginning in May. The ban applies statewide, including the lower Hudson River, where terrapins also are found.

Terrapins in the early 20th century were actively harvested for turtle soup, a practice encouraged by the lack of regulations on their capture.

The DEC said the final diamondback terrapin season will close April 30, and licenses will expire May 4.

“I’m thrilled New York’s conservation leaders followed the science by ending collection of these beautiful little turtles,” Elise Bennett, an attorney for the nonprofit Center for Biological Diversity. The group, along with the New York Turtle and Tortoise Society, HerpDigest and other turtle experts, pushed for the trapping closure.

“Closing the hunting season is an important step in the conservation of diamondback terrapin populations in New York,” said DEC Commissioner Basil Seggos.

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Despite the apparent urgency of the rule change, few terrapin hunters exist, and the official legal harvest is zero, according to state figures.

This year, DEC has issued seven special licenses for the commercial harvest of diamondback terrapins, including two from Island Park.

While there is no population estimate, the DEC agency said, “Populations have not rebounded from 20th century overharvesting.”

Robert Zickmund, 61, a veteran lobsterman from Mount Sinai, received one of the few terrapin licenses issued in 2014, he said, partly as an act of protest against the state, which manages fisheries.

“I never caught a turtle,” said Zickmund, whose license has since expired. Declines in lobsters and an inability to get a much-coveted whelk license led Zickmund to give up fishing, he said.

Terrapins face a greater threat from accidental capture by crab trappers and other fishers than by dedicated hunters. The DEC in 2014 first proposed measures to require commercial crabbers to retrofit their traps to prevent terrapins from getting caught and drowning. The measure was passed by a marine advisory council, and the DEC was moving to enact it this year.

Terrapins were identified as a “Species of Greatest Conservation Need” in the DEC’s 2015 New York State Wildlife Action Plan “due to documented threats from habitat loss, nest predation, and incidental capture.”