Fishermen in Florida have been reporting strange behavior from fish in the Florida Keys since October 2023, with fish seen spinning upside down and circularly swimming near the bottom. At least 47 critically endangered smalltooth sawfish have died.
Scientists have been investigating the cause but initially found no issues with water quality or red tide. Removing affected fish from the water led to some recovering quickly.
Testing has found elevated levels of Gambierdiscus algae in the water and seafloor. Toxicology research identified a number of natural algal toxins present in both water and fish tissue samples.
A leading hypothesis is that a combination of toxins from benthic algae, possibly from multiple species, are interacting and causing neurological effects in the fish. However, the trigger for the algal bloom and toxin proliferation is still unknown.
Efforts are underway to rescue sawfish, with some stabilized in clean water initially but later deteriorating. The death of one sawfish that underwent treatment is being analyzed for clues.
The crisis adds pressure to local scientists and has wide-ranging economic and ecological impacts if not solved, but many key fisheries seem presently unaffected. Continued research aims to confirm causes and mitigation strategies.
Source: NBCNews
