DEMYSTIFYING DEMOIC ACID: UNDERSTANDING ITS ORIGIN, IMPACT, AND RISKS

The oceans are vast and teeming with life, but they can also harbor hidden dangers. One such danger is domoic acid, a naturally occurring toxin that can have detrimental effects on both marine life and humans. In this article, we will delve into what domoic acid is, its sources, how it affects sea creatures, who should stay away from it, and what happens when humans consume it.

WHAT IS DEMOIC ACID?

Domoic acid is a potent neurotoxin produced by certain species of phytoplankton, which are microscopic algae found in marine environments. This toxin belongs to a group known as the amnesic shellfish toxins and is particularly notorious for its harmful effects on marine ecosystems and organisms.

SOURCES OF DEMOIC ACID

Domoic acid is primarily produced by diatom species, such as Pseudo-nitzschia. These diatoms can multiply rapidly, forming harmful algal blooms (HABs) when environmental conditions are conducive. HABs are often triggered by factors like warm water temperatures, nutrient runoff, and changes in ocean circulation patterns.

HOW DO SEA CREATURES GET DEMOIC ACID & WHAT SOME RESCUE CENTERS ARE DOING ABOUT IT?

Filter-feeding marine creatures, such as shellfish (e.g., mussels, clams, and oysters), can accumulate domoic acid when they ingest the toxic phytoplankton as part of their diet (read the list of creatures to avoid coming up in a later section). These shellfish do not metabolize the toxin efficiently, leading to its accumulation in their tissues.

This toxin can have detrimental effects on sea lions, among many sea life, along the California coast, including those at the Pacific Marine Mammal Center in Laguna Beach. Here's how it impacts these marine mammals:

1. Neurological Symptoms: Domoic acid poisoning primarily affects the neurological system of sea lions. When sea lions ingest fish contaminated with domoic acid, it can lead to a condition known as amnesic shellfish poisoning (ASP). This toxin binds to receptors in the brain, leading to various neurological symptoms.

2. Disorientation: Sea lions exposed to domoic acid may become disoriented and exhibit abnormal behaviors. They can appear lethargic, confused, and may have difficulty navigating their environment.

3. Seizures: One of the most distressing effects of domoic acid poisoning is the occurrence of seizures in affected sea lions. These seizures can be severe and life-threatening.

4. Respiratory Distress: Some sea lions exposed to domoic acid may experience respiratory distress, which can be a secondary effect of the neurological symptoms.

5. Stranded Sea Lions: Due to the neurological impairment caused by domoic acid, sea lions may become stranded on beaches or in unusual locations. They are unable to forage effectively or care for themselves.

6. Human Health Concerns: Domoic acid can also pose a health risk to humans who consume contaminated seafood. Health authorities closely monitor the levels of domoic acid in seafood to prevent human consumption of contaminated products.

7. Environmental Impact: The presence of domoic acid in marine environments can disrupt the food chain. It can harm not only sea lions but also other marine life that feed on contaminated fish and shellfish.

Efforts are made by organizations like the Pacific Marine Mammal Center and government agencies to monitor and rescue affected sea lions. When sea lions are found in distress due to domoic acid exposure, they are rehabilitated and, if possible, released back into the wild once they have recovered.

It's important to recognize the role of domoic acid in affecting the health of sea lions and the broader ecosystem along the California coast. Monitoring and research efforts are ongoing to better understand and mitigate the impact of this toxin on marine life.

WHO SHOULD STAY AWAY FROM DEMOIC ACID-CONTAMINATED SEAFOOD?

Consumption of seafood contaminated with domoic acid can be dangerous, especially for vulnerable populations. Pregnant women, nursing mothers, young children, and individuals with compromised immune systems are at a higher risk of experiencing severe effects from domoic acid exposure. It is advisable for these groups to avoid consuming seafood sourced from areas with known algal blooms or domoic acid contamination.

SEA CREATURES TO AVOID EATING

In regions prone to HABs and domoic acid contamination, authorities often issue advisories to warn against the consumption of specific seafood. Commonly affected species include mussels, clams, scallops, crabs, and certain types of fish, such as anchovies and sardines. It is essential to heed these advisories to minimize the risk of domoic acid poisoning.To reduce the risk of domoic acid poisoning, it's advisable to avoid or limit the consumption of the following foods:

1. Mussels: Mussels are filter-feeding shellfish that can accumulate domoic acid if they feed on contaminated algae.
2. Clams: Like mussels, clams are filter feeders and can accumulate domoic acid if they ingest contaminated algae.
3. Razor Clams: Razor clams, which are often found along sandy shorelines, can also accumulate domoic acid and should be avoided during closures or when warnings are issued.
4. Scallops: Although scallops are not as commonly associated with domoic acid poisoning as mussels and clams, it's still advisable to exercise caution and check for local advisories.
5. Crabs: Some types of crabs, particularly those that feed on contaminated shellfish or algae, can contain domoic acid. Be cautious when consuming crabs from areas with known contamination.
6. Anchovies and Sardines: These small fish can sometimes contain domoic acid, as they feed on plankton and algae. However, the risk is generally lower than with shellfish.
7. Squid: Squid can accumulate domoic acid in their tissues, so it's wise to be cautious when consuming them, especially during algae bloom events.
8. Fish that Feed on Affected Species: Larger predatory fish that feed on smaller fish or shellfish with domoic acid may also carry traces of the toxin. Be aware of potential risks, especially if you consume fish from areas with known contamination.
9. Fish Roe (Caviar): Roe from fish like herring and salmon can sometimes be contaminated with domoic acid. Check for advisories before consuming.

It's important to note that not all seafood is contaminated with domoic acid, and the risk can vary by location and time of year. To stay safe, always check for local advisories and closures issued by health authorities or fisheries agencies. Additionally, if you're unsure about the safety of seafood, it's a good idea to consult with local experts or health officials for guidance.

EFFECTS OF CONSUMING DEMOIC ACID

When humans consume seafood contaminated with domoic acid, they can experience a range of symptoms collectively known as amnesic shellfish poisoning (ASP). These symptoms can vary in severity and may include nausea, vomiting, diarrhea, abdominal cramps, headache, dizziness, and confusion. In severe cases, ASP can lead to seizures, coma, and even death.

Domoic acid primarily affects the central nervous system, leading to memory impairment and, in extreme cases, permanent brain damage. Prompt medical attention is essential if someone exhibits symptoms of ASP after consuming contaminated seafood.

WRAPPING IT ALL UP

Domoic acid serves as a stark reminder of the intricate balance within marine ecosystems and the potential risks associated with seafood consumption. While regulatory agencies and monitoring programs work diligently to safeguard public health, it is crucial for individuals to stay informed about local advisories and exercise caution when enjoying seafood harvested from areas prone to algal blooms and domoic acid contamination. By understanding the origins and consequences of this toxin, we can better protect both our oceans and ourselves from its harmful effects.