Spinning Fish in the Florida Keys

Over 60 species have exhibited these abnormal behaviors, including silver mullet, tarpon, permit, snook, bonefish, pinfish, bigeye scad, ballyhoo, jack crevalle, yellow jack, blue runner, southern stingray, mutton snapper, mangrove snapper, cubera snapper, lane snapper, leatherjacket, yellowfin mojarra, scaled sardine, toadfish, goliath grouper, blue striped grunt, redfish, lemon shark, Atlantic sharpnose shark, smalltooth sawfish, and spadefish.

An inter-institutional research study to identify the cause of these symptoms began on January 11, 2024. Partners include Bonefish & Tarpon Trust, Lower Keys Guides Association, Florida Gulf Coast University (FGCU), University of South Alabama (USA),  Florida International University, Woods Hole Oceanographic Institute (WHOI), Florida Department of Environmental Protection (FL DEP), and Florida Fish and Wildlife Conservation Commission (FWC).

Symptomatic fish continue to be observed consistently and are more frequently observed at night.  As of mid-March 2024, BTT and the Lower Keys Guides Association had received 182 reports of symptomatic fish, with almost all reports from inshore seagrass and flats systems. This stressor has affected forage fish, game fish, sharks and rays—and everything in between. Only two reports have been from the reef, Hawks Channel or shallow and deep gulf waters. The remainder have occurred in our inshore seagrass and flats systems. In mid-February, most of the reports occurred west of Big Pine Key and east of Sugarloaf Key, but have now expanded to the east and west.

BTT is working closely with over 65 local professional fishing guides and captains across the Florida Keys to track the spread and intensity of the spinning fish phenomena through a Rapid Response Network launched in April 2024. This has allowed BTT to track the phenomenon into the Upper Florida Keys, and target collections of fish and water samples from these new zones.

Local fishing guides are supporting BTT in weekly research trips to collect fish and water samples for toxin and algal cell analysis and provide a platform for researchers with BTT to conduct field studies on fish recovery.

Helpful Links

• FWC Sawfish Hotline
• Report a Fish Kill or Abnormal Fish Behavior Reports to FWC
• Report Unusual Fish Behavior to the LKGA
• Florida Department of Health Fish Consumption Advisories
• Florida Department of Health Swimming Advisories

Initial Research Findings

In the collaborative study led by BTT and LKGA, four lines of inquiry are being explored. These include: contaminants and synthetic compounds (FL DEP, FIU), water column harmful algal blooms (FWC), benthic harmful algal blooms (FGCU, WHOI, USA/DISL), and fish health (FWC). BTT and LKGA have coordinated and executed multiple sampling events to collect symptomatic fish and paired water samples.

Research to date has found that:

• All sampled fish showed no known viruses, parasites, or organ abnormalities.
• No red tide was detected in surface water samples, and FL DEP have not detected common contaminants.
• Water parameter readings (oxygen, salinity, and temperature) are typical.
• Analyses have been conducted by USA/DISL including cyanobacterial toxins, saxitoxins and domoic acid, but were not detected in water, algae, or fish samples to date. Other algal toxins, however, have been detected.
• Benthic algal samples from the Lower Keys were shown by FGCU to have elevated concentrations of a dinoflagellate in the genus of Gambierdiscus occurring in areas where symptomatic fish are present. Gambierdiscus can produce multiple types of neurotoxins that can cause behavioral effects in fish. These toxins and others produced by other benthic dinoflagellate taxa are being targeted for further analysis by USA/DISL.

Ongoing toxin testing and sampling of various fish tissues will determine its overall impact and potential impact to fisheries. As we learn more, we will provide information on BTT’s social media channels and update this page.

Watch the May 2024 Live Update