Marine toxins are naturally occurring chemicals that can contaminate certain seafood. The seafood contaminated with these chemicals frequently looks, smells, and tastes normal. When humans eat such seafood, disease can result. The most common diseases caused by marine toxins in United States in order of incidence are scombrotoxic fish poisoning, ciguatera poisoning, paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnesic shellfish poisoning.
Marine toxins are produced by algae or bacteria and are concentrated in contaminated seafood. Substantial increases in seafood consumption in recent years, together with globalization of the seafood trade, have increased potential exposure to these agents. Marine toxins produce neurological, gastrointestinal, and cardiovascular syndromes, some of which result in high mortality and long-term morbidity. Routine clinical diagnostic tests are not available for these toxins; diagnosis is based on clinical presentation and a history of eating seafood in the preceding 24 h.
There is no specific antidote for ciguatoxin or maitotoxin poisonings. Treatment is generally for specific symptoms and includes supportive care. Intravenous mannitol has been reported in uncontrolled studies to reduce the severity and duration of neurologic symptoms, particularly if given within 48 hours of the appearance of symptoms.
Overfishing is significantly increasing due to the global food crisis, caused by an increasing world population. Organic matter (OM) pollution and global warming (GW) are key factors that exacerbate these challenges (e.g. algal blooms), to which acidification in marine waters should be added as well. Sources, factors, mechanisms and possible remedial measures of these challenges to marine ecosystems are discussed, including their eventual impact on all forms of life including humans.