After a devastating oil spill earlier this month, several marine animals who were saved died this week.

According to The San Diego Union-Tribune, two sea lions and one elephant seal were brought to SeaWorld San Diego last week when an oil spill occurred near Santa Barbara, CA.

Jennicca Taylor, a spokeswoman for the park, said that one of the lions had to be euthanized after being found unresponsive for seizures.

The three mammals came to the park covered in oil and were malnourished. Necropsies are to be performed to find the exact causes of their deaths.

Since the spill, SeaWorld’s Oiled Wildlife Care Center has received 17 sea lions and five elephant spills. On Thursday, three more sea lions were brought to the center to be cleaned, hydrated and stabilized.

Fox 5 San Diego reports that three specialists with SeaWorld’s team are remaining at the beach along with a bird specialist to help clean up oil-drenched birds affected by the spill.