Algal Bloom: Domoic Acid Poisoning Hits Santa Barbara Sea Lions, Hundreds Treated

In Ventura and Santa Barbara counties, a harmful algal bloom is to blame for the domoic acid poisoning of hundreds of sea lions that are washing up on the shore.

Since then, environmentalists have cared for the stranded wildlife.

Harmful Algal Bloom

A harmful algal bloom, or HAB, is when certain types of algae rapidly multiply and have a negative impact on both people and marine life.

Domoic acid, a neurotoxin made by the algae that build up in shellfish and causes seizures in marine mammals, particularly affects Central Coast sea lions.

Maggie Broadwater, a research scientist from the National Centers for Coastal Ocean Science (NCCOS), said that the presence of high levels of toxins in their food and environment can cause acute exposure in sea lions.

They are given a clean source of food when they are taken to marine rehabilitation centers because they process the toxin and eliminate it through feces and urine.

According to Clarissa Anderson, the executive director of the Southern California Coastal Ocean Observing System, due to the diatom pseudo-high nitzschia's levels of domoic acid production, marine ecosystems are at risk.

Anderson said that it becomes a crisis when an acute event occurs that has persisted for several weeks and causes the algae to continue to bloom and proceed to produce this toxin that enters the base of the food chain.

Domoic Acid Poisoning

Fish eat the toxin, which then spreads to sea lions as well as other marine mammals.

It may even present a risk to people in certain situations.

Amnesic shellfish poisoning is an illness that causes short-term brain damage, memory loss, and, in extreme cases, death.

It can be contracted by eating contaminated shellfish.

Anderson added that it can be fatal, and in fact, the existence of this toxin in the environment was discovered in 1987 when 10 people who ate wild-caught mussels on Prince Edward Island, which is located in Canada, have died as a result.

The risk of domoic acid poisoning in humans is currently low, however, because the state strictly checks seafood for biotoxins.

Climate Change and Extreme Weather

Weather patterns and "overfeeding" from nutrients from land that enter the ocean are the main causes of harmful algal blooms.

Anderson claimed that a HAB event of this size happening on the Santa Barbara Channel this close to the end of the year is unusual for the Central Coast.

This late-September toxic bloom's origin is still a mystery to scientists.

Although it is difficult to determine, recent heat waves and climate change may make the issue worse.

HABs are caused by a variety of factors.

It is not a simple question to answer, according to Quay Dortch, a senior HAB scientist from NCCOS. The growth rate rises as the temperature rises, but eventually, it becomes too hot and stops growth.

He went on to say that a variety of factors, including rainfall and the number of nutrients that enter the coastal zone with it, can have an impact on toxicity.

There are good years and bad years when it comes to HAB events. A domoic acid outbreak in 2015's marine heat wave, which swept from California to the coast of Washington, was one of the worst.

Dortch said that the toxin was ingested by a wide range of organisms, not just sea lions, and it had significant effects on all of them.

The long-term closure of the Dungeness crab fishery had significant negative economic effects.

According to Anderson's team's research findings, domoic acid events appear to be getting worse in California, indicating that they have undoubtedly grown larger and more toxic.

The toxins just appear to be produced in greater quantities when they bloom.

Although there is little that humans can do to stop HABs from occurring, scientists have become more adept at foreseeing them.

C-HARM is a domoic acid forecasting system that was developed by NASA and the National Oceanic and Atmospheric Administration.

To assess the potential for marine domoic acid poisoning in their region, marine rescue centers refer to C-HARM maps.

Anderson said that a real-time forecasting system that resembles a weather map can be made using a variety of data sources, including satellites, models, and water sampling.

The non-profit Channel Islands Marine and Wildlife Institute is rehabilitating sea lions on the Central Coast and is currently accepting donations to support their work, KCBX FM Central Coast Public Radio reported.