From January 30 to February 3, a cold snap swept across South Florida, impacting the region's fisheries. Bonefish & Tarpon Trust responded by partnering with Florida International University (FIU) to document the event. What follows is a summary of the findings to date.
Positioned in subtropical latitudes, episodic cold spells can act as an important structuring force for our marine fish and wildlife communities in South Florida. (A structuring force is an environmental condition or event that dictates which species are present or absent in our marine environment.) Many of us remember the impact of the 2010 cold spell that resulted in a 95% loss of snook in Everglades National Park (ENP), killed over 100 crocodiles and over 70 manatees, and was the final nail in the coffin to kill the historic Keys bonefish fishery. The 2010 event held water temperatures at stressful levels (below 60°F) for 12 days, and at lethal levels (52°F) for many tropical species for four days at the Marathon bayside hydrostation. Similar large-scale fish kills impacting tarpon, snook, and other species occurred in other regions, including Charlotte Harbor, Tampa Bay, and Indian River Lagoon. These temperatures marked the most severe cold snap South Florida experienced in over 100 years.
The weather forecast 10 days ago reminded us of the conditions 2010 brought and the catastrophic losses it caused to our fisheries. In anticipation of this event, BTT organized a scientific response effort to characterize its impacts in partnership with FIU. The response effort involved seven teams of scientists and fishing guides who executed search patterns from Biscayne National Park to the Marquesas on Tuesday and Wednesday this week (February 4th and 5th). Teams measured water temperatures and water quality parameters, identified and counted all dead species, and collected dead bonefish, goliath grouper, permit, and tarpon for necropsy.
Our teams found that this event, though a once in a 15-year episode, was considerably less severe than the 2010 event. It kept water temperatures at stressful temperatures for four days, and did not reach lethal levels at the Marathon bayside hydrostation. However, our teams observed similarities between 2010 and 2026. The species communities and areas affected were the same, consisting of tropical species, with mortalities being highest in the shallow waters of Florida Bay and Islamorada, tapering off west of Channel 5. On the water, our teams noted water temperatures in central and upper Florida Bay that were 11 degrees °F colder than temperatures in the Lower Keys and Key West.
Unlike the 2010 event, snook, tarpon and bonefish populations resisted catastrophic mortalities. Only 10 bonefish were recovered by our seven teams. And guides only reported six additional bonefish mortalities, which we were unable to recover. In comparison, over 100 bonefish were collected at white marlin beach (Lower Matecumbe) alone in 2010. All bonefish that perished in the recent cold event were juveniles or subadults. Surprisingly, few snook were reported dead; our teams recorded less than 20 dead snook in central and upper Florida Bay. Aerial surveys conducted by ENP staff also identified a small pocket of snook mortality near Garfield Bight. In 2010, there were thousands of dead snook observed in Florida Bay and ENP.
Though the resistance of snook and bonefish populations to this episodic event is optimistic, two other fisheries, barracuda and goliath grouper, suffered mortalities that will be noticed by anglers. Our teams recovered 26 dead goliath groupers, with many more reported dead. Similarly, barracudas across the archipelago experienced mortalities particularly in central Florida Bay.
Farther north in Indian River Lagoon and Charlotte Harbor, BTT staff and collaborators reported low to moderate levels of snook and tarpon mortalities, with most in the subadult and juvenile size categories.
From a conservation perspective, this event did reveal a point of vulnerability for our bonefish fishery in Biscayne Bay. Bonefish use the warm waters of canals as wintertime refuges. We commend the Florida Fish and Wildlife Conservation Commission (FWC) and Biscayne National Park (BNP) law enforcement for committing additional officers to monitor these canals for illegal fishing activity. As extreme cold events impact our fisheries, there is a strong need to be proactive and vigilant to ensure the sustainability of our tropical resources.
We thank the scientists and fishing guides who committed time to this effort.
Scientists: FIU Santos Seascape Ecology Lab @santos_seascape_ecology, FIU Fisheries Lab @fiu_fisheries_lab, FIU Marine Biology @fiumarinebio, FIU Institute of Environment @fiuenvironment, FIU Biology @FIUBiology, Ocean First Institute @oceanfirstinstitute, Sophia Costa, Jennifer Rehage, Alia Jones, Camille Demaire, Gina Badlowski, Jose Trujillo, Chris Malinowski, Ross Boucek, Jessyca Labadie.
Fishing Guides: Shawn McKay, Dave Perkins, Chris Wilson, Rich Hastings, Greg Dini, Will Benson, Will McCabe, Nate Weinbaum, Eric Rodriguez, Adam DeBruin, Chris Perez.