The owner of a shuttered Los Angeles-area sushi restaurant has pleaded guilty to allowing meat from the endangered sei whale to be served at the upscale establishment, in a case that outraged animal rights activists, a federal prosecutor said on Tuesday.

Brian Vidor pleaded guilty in federal court in California on Monday to one count of illegally selling whale meat at his Santa Monica restaurant, The Hump, according to assistant U.S. Attorney Dennis Mitchell.

The restaurant, which was located at the Santa Monica Municipal Airport, closed in 2010 as a result of an undercover federal investigation. A sister restaurant, Typhoon, remains open.