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Florida Keys Abnormal Fish Behavior Event Fall 2023 - Present

Updated July 17, 2024

Sawfish Mortalities Fish Kill Hotline Reports Fish Samples Collected Water Samples Collected





Table contains number of samples (water, fish) collected by or submitted to FWC. Number of hotline reports includes partner submissions from Bonefish & Tarpon Trust, Lower Keys Guides Association, and the Sawfish Hotline.
View a breakdown of sample collection.


Reports of spinning fish from the Florida Keys started in the fall of 2023 and smalltooth sawfish mortalities were first reported in January 2024. It is possible that these two events could be related.

Spinning Fish Update

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  • Dissolved oxygen, salinity, pH, and temperature are not suspected to be the cause of the fish behavior or kills.
  • DEP has conducted water testing for more than 250 chemicals within the area of interest. All parameters were either not detected or were below any biological thresholds, with most being below minimum detection limits. Sediment sampling results for heavy metals are pending.
  • Based on fish necropsy data to date (excluding sawfish), there are no apparent signs of a communicable pathogen, and tested specimens do not support bacterial infection. Histological examination is ongoing.
  • Testing of water and fish tissue did not indicate that red tide (Karenia brevis) was the cause.
  • Other harmful algal species have been observed in benthic and water samples examined by FWC and Florida Gulf Coast University (FGCU). Associated toxins have been detected in water and benthic samples, and fish tissues, by the University of South Alabama, but more work is needed to determine if this is the cause of the unusual behavior.
  • Elevated levels of the HAB, Gambierdiscus spp., were observed in water and benthic samples early on in the response by FWC and FGCU. However, samples (water and benthic) from March 2024 had lower levels and were more in line with densities measured in pre-event sampling from Monroe County. 
  • FWC has sent >300 fish tissue samples to the University of South Alabama for toxin analyses.

Sawfish Update

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  • FWC has sent 12 smalltooth sawfish tissue samples as well as sawfish blood samples (including pre-event samples) to the University of South Alabama for toxin analyses.
  • The smalltooth sawfish rescued by Mote Marine Laboratory and FWC on April 5 unfortunately had to be euthanized at Mote's facility on May 2.
  • Additional information on deceased rescued sawfish.
  • FWC staff have conducted necropsies on recovered smalltooth sawfish, blood and tissue samples are currently under analysis.
  • Social media posts:

About this Event

A man and two women are standing outside next to a large metal table that is holding a large dead sawfish.

The Florida Fish and Wildlife Conservation Commission (FWC) is documenting reports of abnormal fish behavior (spinning) in the Keys. There have also been reports of small-scale fish mortalities in these areas. More recently, there has been a series of smalltooth sawfish mortalities that could be related to this event. Some sawfish have exhibited spinning behavior before dying. At this time, the cause of this abnormal behavior and these mortalities is not known. Ongoing efforts involve the collection and analyses of water and tissue samples and coordinating the recovery of endangered smalltooth sawfish carcasses for necropsy, and initiating a rescue and rehabilitation response for smalltooth sawfish.

The FWC is working collaboratively with the Florida Department of Environmental Protection (DEP), Florida Gulf Coast University, University of South Alabama, Bonefish & Tarpon Trust, and the Lower Keys Guides Association as well as other federal, state, local agencies, non-government organizations, stakeholders and the community to actively investigate this abnormal behavior.

Working with NOAA Fisheries, the FWC is participating in the emergency response effort with partners to rescue and rehabilitate smalltooth sawfish affected by this mortality event. On April 5, 2024, the first rescue of a 11-foot male smalltooth sawfish from Cudjoe Key was transported to Mote Marine Laboratory’s facility for rehabilitation. Additional participants in this rescue include: Havenworth Coastal Conservation, Ripley’s Aquariums, Mote Marine Laboratory, and Dynasty Marine Associates, Inc.


How You Can Help

Public reports are an essential resource for our investigation into this event. 


Over 50 species impacted including Atlantic Needlefish, Atlantic Stingray, Ballyhoo, Barracuda, Bigeye Scad, Blacktip Shark, Blue Crab, Blue Runner, Blue Striped Grunt, Bonnethead Shark, Boxfish, Dog Snapper, Eagle Ray, Flying Fish, French Grunt, Glass Minnow, Goliath Grouper, Gray Snapper, Gray Triggerfish, Grunt, Jack Crevalle, Key Silverside, Leatherjacket, Lemon Shark, Lane Snapper, Lionfish, Lookdown, Mangrove Snapper, Mojarra, Mutton Snapper, needlefish, Nurse Shark, Permit, Pilchard, Pinfish, Pipefish, Porkfish, Remora, Sand Perch,  Sargent Major, Scaled Sardine, Silver Jenny, Silver Mullet, Smalltooth Sawfish, Snook, Spanish Mackerel, Southern Stingray, Spider Crab, Stone Crab, Striped Mullet, Stoplight Parrotfish, Tarpon, Toadfish, unidentified snapper, unidentified baitfish, unidentified stingray, White Grunt, Yellowfin Mojarra.

Updated 5/22/2024

All fisheries in the Florida Keys that are open, remain open. Please be sure to follow all rules and regulations when you head out on the water.

Harvesting distressed or dead animals is not advised under any circumstances. For more advice on consumption or to report a suspected fish-related illness, please contact your local county health department or call the Florida Poison Information Hotline 1-800-222-1222.


Swimming where there are dead fish is not recommended. Please report any fish kills to the Fish Kill Hotline, 800-636-0511 or