Recently released statistics show that 2005 was one of the worst years ever for Florida’s manatee population. One of the leading causes of death was “Red Tide”. Scientists have now linked the effects on the manatees to the human population. Red Tide, or blooms of the algae Karenia brevis, release toxins which cause respiratory effects as well as immune depression. The red tide events seem to be increasing, especially on Florida’s west coast. One controversial theory for this increase says that nutrient pollution from runoff may contribute to the widespread growth of the algae. The National Institute of Health began studying the problem in 2000. Their study looked first at the effects of the red tide toxins on mice. The mice surprisingly did not show any respiratory effects, but did show signs of immune suppression. This evidence supports recently documented new illnesses in dolphins and other marine animals, and causes concern for the far reaching implications on the exposed human population. The research team also reviewed health records for local emergency rooms, which showed that respiratory problems such as asthma and bronchitis increased during the red tide events. When the team investigated further they found that while red tide events were thought to mainly affect the respiratory system, research showed that the manatees were also killed by eating sea grasses that contained the toxins long after the blooms were gone. This caused them to believe that humans may also be affected by eating seafood exposed to the red tide toxins. Although “Red Tide” has always been thought to affect mainly marine life, these recent studies have shown it to affect the human population also. The far reaching implications could be enormous, especially for the people who live in often infected areas, as well as for the seafood industry. Further research is necessary to determine how the brevotoxins may be controlled, and how
Cited: Harbor Branch Oceanographic Institution. “Red Tide Impacts Increasing for Endangered Manatees and Humans.” Biology News Net (Feb 26, 2006): 1-3.