Sawfish mortalities and fish kill reports faltering

Sawfish mortalities and bizarre fish behavior have been reported in the Florida Keys and other parts of Florida as far back as Fall 2023. Scientists aren’t sure exactly what is causing the event but are beginning to piece together the difficult puzzle.

From fish swimming in an endless loop to endangered smalltooth sawfish flailing ashore and thrashing their rostrum.

Florida Fish and Wildlife Conservation Commission updated the Florida Keys Abnormal Fish Behavior Event statistics on Wednesday. And the numbers may lead you to believe the tide may be turning in favor of the fish.

“Almost basically 10% of the population died within a couple of months. That’s just not sustainable,” said Mike Parsons the director of Florida Gulf Coast University’s Water School.

That’s how the sawfish mortality and abnormal fish behavior event started. Numbers began dropping off since FWC began weekly updating reported sawfish mortalities.

Adam Brame, the recovery coordinator for the Southeast regional office of the National Marine Fisheries Service (NOAA FISHERIES) told WINK News one reason that may be.

“This time of the year makes these migrations up the up the coast,” said Brame. “Even if there was something in the water that was causing this, they’re no longer there in the same density that they were earlier the year.”

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Even though the trend seems to be swinging in favor of the fish, Brame did note that the total mortality count may not tell the whole story.

“At this point, I think there’s 54 confirmed mortalities of sawfish, we expect that number to be quite a bit higher,” said Brame.

Parsons explained how the event may be associated with a harmful algae bloom.

“It seems to be related to toxins that are produced by benthic micro algae,” said Parsons. “We saw a lot of them they were elevated over the wintertime, and now their numbers are starting to decrease.”

Since FWC began tracking the abnormal event at the end of January, 54 sawfish mortalities have been reported. The good news is that that number has only grown by eight in the last two months. That is a considerable drop off to the 26 mortalities from the two months prior.

“Sawfish that have died to this point are the adults or young juveniles that are actively involved in the reproduction of sawfish,” said Brame. “And so when you’re removing those from the population, what kind of impact does that have on the species’ ability to recover?”

Despite the bad news, the good news is that reported fish kills are also dropping. 508 fish kill reports have been made since the end of January, but only ten fish kills have been reported in the last month. That makes the last four weeks the fewest one-month fish kills reported to date.

Florida Fish and Wildlife sent WINK News a statement related to the fish kill and sawfish mortalities. You can see that below.

“FWC and partners continue to investigate the cause of spinning fish and sawfish mortalities in the Keys. This event was first identified in the Fall of 2023, with the first sawfish mortality in December of 2023. As of July 17th, 54 sawfish have been found deceased. A number of Harmful Algal Bloom (HAB) species endemic to the area have been identified in water samples and their associated toxins have been detected in water samples and fish tissues, 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 Florida Gulf Coast University, but research is ongoing.”

Click here to learn more about smalltooth sawfish from FWC.

Click here to see FWC’s smalltooth sawfish mortalities listed for each week.

Click here to learn more about sawfish from NOAA Fisheries.