Shellfish poisoning occurs when people consume shellfish contaminated with harmful toxins produced by certain algae. These toxins can accumulate in shellfish like clams, oysters, and mussels, making them dangerous to eat. Symptoms of shellfish poisoning can include nausea, vomiting, diarrhea, and in severe cases, neurological issues. There are different types of shellfish poisoning, such as paralytic shellfish poisoning (PSP) and amnesic shellfish poisoning (ASP), each caused by specific toxins. Monitoring and testing of shellfish populations are essential to prevent outbreaks and protect public health, especially in coastal areas where shellfish harvesting is common.