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Increase in reports of sick sea lions linked to domoic acid toxicosis, experts say

Posted at 4:36 PM, Jun 14, 2019
and last updated 2019-06-14 20:21:40-04

Marine wildlife rescue groups have been responding to an increase in sick sea lions over the past few weeks.

The Channel Islands Marine & Wildlife Institute (CIMWI), which covers Santa Barbara and Ventura counties, says the animals are showing signs of domoic acid toxicosis.

The domoic acid neurotoxin is the result of a naturally-occurring algae. CIMWI explains that filter-feeding animals, including shellfish and small fish like sardines and anchovies, can consume the algae without any ill effects. However, when marine mammals eat the fish and shellfish, it can make them sick.

The toxin targets the central nervous system and brain. Symptoms of domoic acid poisoning in sea lions include lethargy, disorientation, head bobbing and weaving, muscle spasms, seizures, foaming at the mouth, eye bulging, and the inability to move out of the rising tide. Severe cases can result in death.

A California sea lion suffering from domoic acid toxicosis. (Photo courtesy Channel Islands Marine & Wildlife Institute)


CIMWI says that while there is no known cure for domoic acid poisoning, depending on the level of illness, symptoms typically subside after 72 hours as the toxin is eliminated from the animal’s body, and affected marine mammals have been known to recover.

Ronnie Glick, Senior Environmental Scientist with California State Parks, says in the Pismo Beach and Oceano areas, they’ve been coming across three to five sick sea lions per day. Lately, they’ve been mostly large adult females.

On Friday afternoon, The Marine Mammal Center’s facility in Morro Bay had already rescued five sea lions and had calls for at least six other animals in distress.

Sick animals are stabilized at the Morro Bay facility before they can be moved to The Marine Mammal Center’s main location in Sausalito.

Diana Kramer, Operations Manager for The Marine Mammal Center in San Luis Obispo County, says just this week they started seeing sea lions exhibiting symptoms including disorientation and seizures.

She says while it’s too early to say for sure that the animals are suffering from domoic acid toxicosis, the symptoms are similar and domoic acid is typical in the summer.

Kramer says they are extremely busy right now because it is also the middle of sea lion breeding season. In fact, The Marine Mammal Center says more than half of all California sea lions are born in June.

Younger sea lions that are just starting to head out on their own are coming onshore after being unable to find the food they need or they may be sick, Kramer says.

On June 6, Morro Bay Police came across a young, sick sea lion that had wandered into the street. The pup, named “Gunther,” was reportedly malnourished and had abscesses. She is currently receiving care at The Marine Mammal Center’s Sausalito facility.

Kramer says if you see a marine mammal in distress in San Luis Obispo County, call The Marine Mammal Center’s hotline at (415) 289-SEAL. She says it’s best to give the animal space and allow the center’s volunteers to handle the situation. While it may be tempting to want to comfort the animal, Kramer says having people around can actually cause it more stress.

The Morro Bay facility has two staff members and volunteer crews of 4-8 people each day who respond to calls and care for the animals.

If you reported a sick or injured animal to The Marine Mammal Center, you can check its status on the center’s website. Kramer says it typically takes a couple of days for the animals to show up online.

If you come across a distressed marine mammal in Santa Barbara County, call the CIMWI Rescue Hotline at (805) 567-1505.