The metal gates were pulled shut on Sunday, and confused patrons, some thumbing New York City guidebooks, had to look elsewhere for their smoked-fish fix. A bright yellow sign that said “Closed by the order of the commissioner of the Department of Health and Mental Hygiene ” was placed prominently in the window.

Inside Barney Greengrass, the 111-year-old restaurant and Jewish deli, whose sturgeon was mailed to President Franklin D. Roosevelt, chairs were stacked on tables, lights were shut off and a plate of black and white cookies sat uneaten, encased in plastic wrap.

Health inspectors conducted an unscheduled inspection and shut the Amsterdam Avenue establishment on Thursday, the day after Yom Kippur, and following one of the busiest periods of the year for smoked-fish purveyors .

The health department said they closed the store to protect public health.

The health department conducted a routine inspection of Barney Greengrass and observed food not held at the correct temperature; close to 300 mouse droppings, including droppings in the kitchen and food storage areas; live roaches in the kitchen; and “conditions conducive to pests and other food safety concerns,” Danielle De Souza, a spokeswoman for the department, said in a statement.