FWC reporting 17 manatee deaths in Sarasota County so far this year

by

July was worst month, with five cases

Image courtesy FWC

On Nov. 17, the Florida Fish and Wildlife Conservation Commission (FWC) released a report saying that 1,003 manatees — more than 10% of Florida’s estimated population — have died since the start of this year.

The preliminary data, covering the period from Jan. 1 through Nov. 12, listed 17 incidents in Sarasota County, The Sarasota News Leader found in reviewing FWC’s materials. July had the largest number — five. Three incidents were reported in October. The others occurred in January (one); April (one); June (two); August (two); September (two); and this month — one on Nov. 10.

The first death was reported on Jan. 10 in Phillippi Creek, the FWC report said, and the manatee was perinatal, meaning it either was close to birth at the time of its death or it died shortly after birth. Three other perinatal cases were noted throughout the following months.

Natural causes were listed in four cases, while the cause of death was not determined in the remaining incidents.

The deceased manatees were found in water bodies all around the county, FWC pointed out: Phillippi Creek, Lemon Bay, Little Sarasota Bay, Blackburn Bay, Roberts Bay, Sarasota Bay, Cranes Bayou on Longboat Key, Shakett Creek in Nokomis, Forked Creek in Englewood, Midnight Pass on Siesta Key and the Gulf of Mexico.

In three of the Sarasota County cases, the FWC reported, red tide was suspected as the cause of death. Those incidents were included on the list whose heading said, “Manatee Carcasses Collected Within the Known Red Tide Bloom Boundary.”

Since 1976, the highest number of manatee deaths the News Leader found in a single year in Sarasota County were reported in 2018, 52. Of those, 37 were classified as natural deaths, FWC pointed out.

This is part of the FWC data about manatee deaths in Sarasota County in 2018. Image courtesy FWC

In 2018, Sarasota County endured a significant red tide event, as documented by Mote Marine Laboratory and FWC.

This is a sampling of manatee deaths in 2018 in Florida that were linked to red tide. A “+” indicates that red tide toxin was detected by analysis of the manatee’s stomach contents, liver, urine or other sample. A “%” indicates that a low level of the toxin was detected. An asterisk indicates that the carcass was recovered within the known bloom boundary and no other cause of death was apparent. Image courtesy FWC

That year was followed by 2017 with 26 deaths; of those, FWC pointed out, 17 were attributed to natural causes.

The next highest death figures, by year, follow: 2013, 24; 2005 and 2016, 20; 2006, 19; 2003, 18; 2009, 17; 2002, 15; and 1999, 14.

On its Florida Manatee Program webpages, FWC notes that manatees “are considered one of the state’s keystone species whose behavior can alert researchers to the environmental and habitat changes that may otherwise go unnoticed in Florida waterways for extended periods of time.”

As herbivores, the webpages explain, manatees “feed on a variety of submerged, emergent and floating plants. These plants not only provide food to Florida’s manatees, but are also an important component of marine and freshwater ecosystems.

The webpages add, “Manatees are known to consume all species of seagrass found in Florida …”

Seagrass is the primary food for manatees, FWC points out. Image courtesy FWC

Among the threats to aquatic vegetation FWC lists are the following:

  • “Excessive nutrient run-off from land,” which can lead to phytoplankton blooms.
  • “Dredging of waterways.”
  • “Removal of shoreline vegetation and construction of seawalls.”
  • “Shading from docks.”
  • Increased sediment from shoreline and offshore construction.

People can help manatee conservation by reporting injured, distressed or dead manatees to the FWC Wildlife Alert Hotline at 888-404-3922, an FWC news release says.

Additional opportunities to assist the mammals may be found at MyFWC.com/Manatee. Click on “Support Manatee Conservation.”