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Sarasota Bay is a local exception to bad news on Florida manatee populations

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Director's Note from David Tomasko, Ph.D., Sarasota Bay Estuary Program Executive Director

2021 was the worst year on record for Florida manatees, with over 1,000 deaths – likely more than 10% of the state’s population. What you may not know is that in the first three months of this year, we are not that far behind what happened last year. During January to March 25th of 2021, we had lost 565 manatees, statewide. Over the same period of time this year, we’ve lost an additional 465 manatees, according to the FFWCC. That is a smaller number than last year, but it is still more than twice as high as the average for the years 2017 to 2020. And because of the hit last year, a slightly smaller number of deaths can be a greater percent decline, due to the reduction in the overall population.

About 3% of the deaths so far this year are “perinatal” and about 39% are females, so this year’s die-off seems to be mostly males and typically not the very youngest manatees. We lost an awful lot of females last year, so it may be that males are disproportionately the survivors of last year’s events.

Sarasota County has only one reported death so far this year, while Manatee County has had three. In contrast, Indian River County has 12, and Brevard County has 290 of the 465 deaths (62%) recorded this year.

Of the 465 dead so far this year, 67% have not been necropsied – most likely due to FFWCC and USFWS staff again being overwhelmed with the number of dead manatees. But the fact that manatee die-offs are centered around Brevard County – as was the case last year - suggests that the manatee die-off is continuing mostly due to starvation, due to a lack of seagrass, due to inadequate water quality in the Indian River Lagoon (IRL). My colleague at the IRL NEP told me that they are starting to see more reports of emaciated dolphins in the IRL, most likely due to the loss of habitat for their major prey species, again due to the collapse of the seagrass ecosystems in the IRL.

A local version of what is happening in the IRL is not out of the realm of possibility, as Sarasota Bay’s seagrass coverage is down by more than 20%, compared to 2016. Tampa Bay has lost 16% of its seagrass acreage since 2018. Charlotte Harbor has lost more than 20% of its seagrass meadows since 2018. In the stretch of Florida between Tarpon Springs and Boca