(NEWPORT, Ore; September 22, 2023) – Public calls reporting sick or dead sea lions on the coast typically increase this time of year as male California sea lions leave California breeding grounds and move north along the West Coast in search of food.
Each fall, some California sea lions die of leptospirosis on Oregon beaches.
Leptospirosis is a naturally occurring bacteria that can sicken sea lions, dogs, people, other wildlife, and livestock. The disease can spread when an animal or person is in contact with urine or other bodily fluids of an infected or dead sea lion.
Beachgoers are urged to leash their dogs and keep dogs and horses at least 150 feet away from live or dead sea lions. Dog and horse owners should discuss the merits of vaccination for leptospirosis with their veterinarian.
The Oregon Marine Mammal Stranding Network is receiving several reports daily of sick or dead sea lions, particularly on the central and northern coast. Many of the sick animals reported are malnourished and very lethargic which is consistent with leptospirosis symptoms. One sea lion was necropsied and tested positive for the disease.
In 2022, an outbreak of leptospirosis occurred. Leptospirosis outbreaks occur sporadically in marine mammals and can result in increased stranding and mortalities among sea lions. While it is too early to know if this will evolve into an outbreak, the Oregon Department of Fish and Wildlife, Oregon State Parks, and the Marine Mammal Stranding Network will monitor the situation. Overall, the California sea lion population is healthy and increasing.
Sick or injured seals, sea lions, whales or dolphins can be reported to the Oregon State Police (OSP) TIP line at 1-800-452-7888.
All marine mammals are protected by the Marine Mammal Protection Act, and it is a violation to disturb, harass, feed, or touch any marine mammal. Marine mammals on the beach are often just resting or are sick and should be left alone.
For more information on leptospirosis, visit ODFW’s fact sheet or the Center for Disease Control website. For more information on wildlife diseases, contact ODFW’s wildlife health hotline at 1-866-968-2600.
