Chappy, the underweight gray seal pup who was found on its stomach on a street in New Haven, Conn., last month, drawing nationwide attention and local police affection, has died, the aquarium that was caring for him announced on Monday.

The Mystic Aquarium in Mystic, Conn., which was treating Chappy in its animal rescue clinic, said in a statement that he had severe digestive problems.

No one knows how Chappy, who was only a few weeks old, wandered about a quarter- or half-mile away from water. But he was suffering from dehydration, malnutrition, and a mild case of pneumonia when New Haven police officers rescued him on Feb. 16, after someone had called 911 to report that a seal was “running back and forth” near a bridge underpass.

Although Chappy responded well to his initial treatment, aquarium officials said, he started to have digestive issues as he transitioned into a whole fish diet, after a diet of diluted fish formula and fluids intended to fatten him up to a normal 35 pounds. The aquarium did not say when he died.

A necropsy performed on Chappy showed that he had died of mesenteric torsion, a twisting of the intestines that cuts off blood supply to a large portion of the gastrointestinal tract.

“This condition can be challenging to diagnose and has a poor prognosis,” the aquarium said in a statement. It said that its staff members were “devastated” by his death.