Researchers presented critical findings on microcystin exposure and its effects on marine life during the Fall 2024 CCHAB Network Meeting held by the California Water Quality Monitoring Council on December 5, 2024. The study, conducted in the Indian River Lagoon (IRL) of Florida, highlights the alarming presence of microcystin, a biotoxin produced by blue-green algae, which poses significant health risks to both wildlife and humans.

The Indian River Lagoon, recognized for its rich biodiversity, has been grappling with declining water quality and increasing harmful algal blooms since microcystin was first detected in the area in 2005. The research focused on two sentinel species—bottlenose dolphins and North American river otters—examining samples collected from 2005 to 2024. The study revealed that 6% of the dolphins tested positive for microcystin, with liver lesions observed in 50% of the dolphins and 18% of the otters examined.

The findings indicate that while microcystin was detected predominantly in the northern section of the lagoon, the health implications for local wildlife are concerning. The lesions observed in the liver tissues of these animals could be linked to microcystin exposure, although other factors such as infectious agents and heavy metals were also considered potential contributors to liver dysfunction.

The researchers emphasized the need for routine monitoring of microcystin levels in both marine wildlife and humans, particularly during algal blooms. They recommended further studies to validate the use of respiratory swabs as a screening tool for microcystin in free-ranging dolphins and to explore the potential health impacts on the local human population.

As the Indian River Lagoon continues to face environmental challenges, the study underscores the importance of ongoing research and monitoring to safeguard both wildlife and public health in the region. Future efforts will focus on expanding toxin screening and understanding the broader implications of harmful algal blooms on the ecosystem.