A reward of up to $20,000 is being offered for information that leads to a conviction in the shootings of California sea lions around West Seattle, the National Oceanic and Atmospheric Administration (NOAA) announced Wednesday.

Since September, more than 12 sea lions have been confirmed shot in King and Kitsap counties, according to NOAA.

“We are concerned about a number of recent reports of marine mammal deaths caused by gunshots in the greater Seattle area. OLE investigates all reported unlawful takes of sea lions,” said Greg Busch, Assistant Director of the West Coast Division of NOAA Fisheries’ Office of Law Enforcement.

RELATED: 12 sea lions shot in Puget Sound area since September

Anyone with information is asked to call 206-526-4300, or the 24/7 hotline for reporting marine resource violations at 1-800-853-1964.

Sea lions are protected by the Marine Mammal Act. The fine for killing a sea lion can be up to a year in prison and penalties of up to $28,520. The illegal killings often have no witnesses, so it's rare anyone is prosecuted for the crime.

Pinnipeds like seals and sea lions have come under mounting pressure for lethal removal as they compete for salmon with Southern Resident killer whales.

NOAA said the number of confirmed shootings this winter are “substantially greater” than in years past.