Scientists Puzzled by Mass Fish Deaths and Unusual Behavior in South Florida

In South Florida, scientists are investigating a perplexing occurrence where hundreds of fish, including the endangered smalltooth sawfish, are washing up dead on the shores. The fish have been observed spinning and whirling before ending up on the shoreline, prompting the Florida Fish and Wildlife Commission (FWC) to classify the event as an abnormal fish behavior incident.

Investigating the Cause

Researchers from various organizations, such as the Water School at Florida Gulf Coast University, the FWC, and the Florida Department of Environmental Protection, are collaborating to uncover the reason behind this unusual behavior. Despite comprehensive testing, no indications of a communicable pathogen have been discovered in the fish necropsies. Furthermore, factors like dissolved oxygen, salinity, pH, temperature, and red tide toxins have been eliminated as potential causes.

Theories

Although the precise cause remains unknown, researchers are considering several possibilities. The presence of a different type of harmful algal bloom or neurotoxin is one potential explanation. The fact that affected fish stopped spinning when placed in clean water suggests that the cause may be environmental. However, additional testing is necessary to identify the specific source of the problem.

Endangered Species at Risk

The critically endangered smalltooth sawfish is of particular concern among the fish deaths. NOAA Fisheries has launched an unprecedented emergency response effort to rescue sick sawfish. The agency has received reports of at least 28 confirmed sawfish mortalities and 265 fish deaths in the affected regions.

Public Involvement and Safety Measures

As the investigation progresses, health officials are recommending that residents refrain from eating any spinning fish or fish caught in areas where spinning fish have been observed. NOAA Fisheries is encouraging the public to report any unusual fish behavior to their hotline or via email. 

Continuing Investigation

The FWC has sent numerous fish samples, including smalltooth sawfish, to the University of South Alabama for further examination. Although several theories are being explored, researchers emphasize that it is premature to speculate on the cause of this unusual fish behavior.