Hundreds of marine mammals on Central Coast beaches sickened by toxic algae bloom

The Channel Islands Marine & Wildlife Institute, which serves Santa Barbara and Ventura counties, has been overwhelmed with an influx of sick or deceased marine mammals with domoic acid poisoning during the past two weeks.

The harmful algal bloom event has been affecting sea animals in Santa Barbara and Ventura counties since May 21, with CIMWI then receiving about one report of a domoic acid-affected animal per day, but the situation worsened on June 8.

The institute reported receiving 250 to 350 reports per day, and as of Tuesday, CIMWI has responded to more than 300 live sea lions showing signs of domoic acid and more than 100 dead sea lions. It also has responded to more than 20 strandings of live dolphins, which can succumb to the neurotoxin quickly, and the death toll for dolphins locally is up to 100.

“We thought last year’s domoic acid event affecting Santa Barbara and Ventura was tragic. This year’s event is even more horrific,” Ruth Dover, managing director for the Channel Islands Marine & Wildlife Institute, said in a recent update. “The number of live and dead stranded marine mammals suspected of having domoic acid rises by the hour.”

Being a small nonprofit organization receiving a large volume of reports each day, CIMWI volunteers have been working nonstop for “10 hours a day in the field and more hours each day behind the scenes for 14 consecutive days,” Dover said.

“Our team members are physically tired and emotionally drained. It is really difficult to watch an animal suffering from domoic acid, and we want to help each and every one of them,” Dover said in the statement. “Our people are volunteering because they care and want to help marine mammals and our ocean. They are investing time, heart, skill and patience. … They are ‘working’ harder and giving more than any one person and team should have to in order to do all they can to help these animals. There are just too many animals suffering from domoic acid with this algal bloom event.

“There are cases we cannot get to and this is not because we don’t care. It is because there are too many animals stranding with domoic acid for us to physically respond to in a day.”

Dover added that many of the animals are being kept under observation with safety perimeters and educational signs.

According to CIMWI, domoic acid is a neurotoxin produced by Pseudo-nitzschia, a microscopic marine algae.

“This phytoplankton grows when our coastal ecosystem provides favorable conditions, such as when upwelling of water causes the nutrients from deeper water to rise to the surface where sunlight is present which proliferates algal growth,” Dover said. “This typically occurs during transitional periods in the spring and fall.”

The toxic algae does not affect filter-feeders — such as small fish, shellfish and bivalves — who consume it, but predators such as sea lions and sea birds who eat these filter-feeders are negatively impacted by the toxin accumulated in the prey. As these predators consume larger amounts of prey, they ingest a higher level of domoic acid.

California sea lions are most frequently exposed to domoic acid because of their habitats and the location of their foraging sites. Signs and symptoms of domoic acid poisoning in sea lions include lethargy, disorientation, head bobbing or weaving, foaming at the mouth, unresponsiveness, vomiting, seizures, inability to move, eyes twitching or bulging, and even death.

According to CIMWI, symptoms typically subside within 72 hours as the toxin is eliminated in urine, and in many cases these sea lions can recover and successfully forage in the wild. However, the degree of domoic acid impact depends on the amount of contaminated fish the sea lion consumes, as consuming too much can result in death.

More information on domoic acid is available on CIMWI’s website.

CIMWI’s response to the reports of sea lions and dolphins stranding and exhibiting signs of domoic acid include dispatching the next available volunteer to drive to the location, walk the beach to find the animal — which can be a mile or more — and conduct physical assessment with photo and video documentation with GPS, tide and beach condition information.

Depending on the size and condition of the animal, as well as the location, level of skill needed, rescue equipment and transport requirements, rescue teams can consist of one to six volunteers.

The rescued animals then receive immediate treatment of aggressive fluid therapy to flush out the toxin, anti-seizure medication if needed, anti-inflammatories to decrease brain swelling from the neurotoxin, and feeding them with fish not contaminated with the domoic acid toxin.

“This is a very physical effort, and with domoic acid, there is an added emotional component on the part of the public and our compassionate volunteers,” Dover said.

The harmful algal bloom events have occurred in Southern California in 2002, 2006, 2007, 2017 and 2022.

“The harmful algal bloom events have increased in frequency and severity in recent decades and increased nutrient pollution and climate change may play a part in this,” Dover said. “Monitoring toxic blooms as well as sick and deceased animals help researchers with enhancing early warning systems to protect wildlife, marine ecosystems and even prevent human illness.”

The Channel Islands Marine & Wildlife Institute advised that people who find a stranded marine animal in distress stay away from and not touch the animal as they are easily stressed by humans and pets, and crowding may cause them to act aggressively or feel threatened and return to the ocean.

People should instead observe the animal from a minimum of 50 feet and call the Channel Islands Marine & Wildlife Institute’s Rescue Hotline at 805-567-1505, providing their name, phone number, specific information about the animal and its condition, and its location — noting any landmarks that can help rescue teams easily find the animal.

Animals in distress can also be reported on CIMWI’s online report form on its website at cimwi.org/online-rescue-form, where they can even include photos of the animal. CIMWI said that is its preferred method for reporting animals in distress.

While Dover said CIMWI has been receiving many duplicate reports about the same animal, community members should still report any animals in distress as it may not have been reported yet.

Noozhawk staff writer Serena Guentz can be reached at sguentz@noozhawk.com .