Tagging Manatees In Cumberland Sound
Catch & Release
In local waters here at the Florida-Georgia border, just off two barrier island shorelines — Cumberland on the Georgia side of the Cumberland Sound, and Amelia on the Florida side of the waterway — marine biologists and veterinarians have been catching manatees. These large marine mammals are being electronically tagged and released for a research project to learn more about their movements. This particular project was first launched in 2015, with this the third season tagging manatees in the Cumberland Sound.
Kings Bay Submarine Base
This study’s goal is to gain knowledge about their activity, especially near the Navy’s Kings Bay submarine base bordering St. Marys, GA. The project is led by Sea to Shore Alliance, the Georgia Department of Natural Resources and Georgia Aquarium. Kings Bay Navy subs and their escort ships travel through the deep channel between Cumberland Island and Amelia Island. The massive black Trident submarines, flanked by their Navy ship escorts, can sometimes be seen in the waterway from along the Fort Clinch State Park shoreline.
According to a news release from the Georgia Department of Natural Resources, Wildlife Resources Division (ST. MARYS, GA 6/14/2017):
“Staff from wildlife agencies and organizations in Georgia and Florida netted the eight manatees in Cumberland Sound May 31-June 2. With a DNR helicopter helping spot the animals, a custom manatee capture boat from Clearwater Marine Aquarium was used to encircle them with a net. They were then pulled onto the boat or a bank to tag and examine. Biologists and veterinary staff, led by veterinarians from Georgia Aquarium and the University of Florida, examined the six male and two female manatees caught, took samples, fitted each animal with a transmitter and released all unharmed.” See their Facebook page below.
DNR Sea 2 Shore Alliance and the Georgia Aquarium are tracking more manatees to understand how these gentle marine…
So far, most of the recently tagged manatees have been hanging around. “As of this week, seven of the manatees were still within 10 miles of their capture site, near Cumberland Island and Florida’s Amelia Island. One had ventured north to the Brunswick area,” according to the Georgia Department of Natural Resources, Wildlife Resources Division news release.
The “Manatee Highway”
In general, scientists are keenly interested in the travels of manatees in the Intracoastal. “The Intracoastal Waterway is like a manatee highway,” according to Georgia Department of Natural Resources’ wildlife biologist Clay George. “But the ICW is also a primary passageway for boats moving up and down the coast, so this behavior may place manatees at added risk of boat strikes.”
Manatee Migration North
The manatee, dubbed the “gentle giant,” was officially designated as Florida’s state marine mammal back in 1975. They migrate seasonally, arriving around the FL-GA border in the springtime when the water warms up, and prefer shallow waters 6 to 7 feet deep. The Florida manatee’s tolerance to cold is limited. They cannot survive prolonged exposure to water temperatures below 68 degrees Farenheit (i.e. 20 Celsius). They depart their spring/summer habitat in northeast Florida and southeast Georgia and return south when water temps drop, usually in October.
How Far Do Manatees Migrate?
A previous long-term manatee study by the U.S. Geological Survey and U.S. Fish and Wildlife Services provided some interesting insights. The study monitored Florida and Georgia seasonal manatee migratory behavior over a dozen years (1986-1998) along the Atlantic East Coast. The data collected over the 12-year study indicated “regions heavily utilized by tagged manatees included Fernandina Beach, FL to Brunswick, GA in the warm season.” Also of interest, the report concluded that “most manatees returned faithfully to the same seasonal ranges year after year.” The research abstract reported that seasonal long distance manatee migration was “a median one-way distance = 280 km (i.e. 174 miles), max 830 km (i.e. 516 miles).”
Spotting Manatees Around Amelia Island
Local islanders know that manatees can be spotted from the Amelia Island shoreline. Boaters often see them while out on the water but also right at Fernandina marina docks. The manatee is attracted to fresh water (known to enjoy being hosed from docks). However, watering is detrimental to the manatee’s safety since attracting manatees to marina docks means they are swimming in areas with heavier boating traffic. Risk of boat strikes is one of the man-made causes of manatee deaths, both “blunt force impacts” and “propeller cuts,” according to the FWC.
“Sea Cows” in Egans Creek
Manatees are herbivores, and migrate to northeast Florida and southeast Georgia in spring for a buffet of marsh grass and other vegetation growing in tidal waterways. Egans Creek is a local foraging habitat attracting manatees into Amelia Island.
We recall an interesting encounter, observing half a dozen manatees feeding in Egans Creek, just off Egans Creek Park on the north side of Atlantic Avenue. Murky water makes it harder to see what’s swimming underneath. The first indication of their presence was seeing the signature water swirls they make, literally circles on the creek’s surface. Since manatees do have to breathe air every three to five minutes when swimming, there is opportunity to catch a glimpse of their heads or hairy snouts protuding the water’s surface.
How Big Are Manatees?
According to the FWC, the typical adult manatee is 9 to 10 feet long (snout to tail), weighs around 1,000 pounds, and consumes 40 to 90 pounds of aquatic vegetation a day (4% to 9% of body weight).
Florida’s Fish & Wildlife Conservation Commission is a state government gatekeeper of manatee information, including mortality data. According to the FWC:
“Don’t feed manatees or give them water. If manatees become accustomed to being around people, they can alter their behavior in the wild, perhaps causing them to lose their natural fear of boats and humans, which may make them more susceptible to harm…The manatee is protected under federal law by the Marine Mammal Protection Act of 1972 and by the Endangered Species Act of 1973, which makes it illegal to harass, hunt, capture or kill any marine mammal. The manatee is also protected by the Florida Manatee Sanctuary Act of 1978, which states: “It is unlawful for any person, at any time, intentionally or negligently, to annoy, molest, harass, or disturb any manatee.”
Florida Manatee Counts Over 6,000
Earlier in 2017, the FWC reported a preliminary count of 6,620 manatees in Florida waters, 3,488 were around Florida’s east coast and 3,132 on the west coast. “The FWC is encouraged by a third straight year of a minimum count higher than 6,000 manatees in Florida waters.” The FWC conducts aerials surveys and also has an ongoing state research project tagging and releasing manatees in Florida.
Florida Manatee Mortalities
In 2017 thus far (Jan. 1 – June 9, 2017), 301 manatee mortalities have been recorded around the state of Florida by the FWC’s Marine Mammal Pathobiology Lab. Boating collisions, red tide and occasional cold snaps are some of the causes of death. For the full calendar year 2016, 520 manatee mortalities were recorded (20% were due to watercraft). Back in 2010, an unusually large number of manatees died from Florida cold snap when, 282 perished from cold stress.
When boating, carefully follow posted speed signs in waterways, also learn more about Guidelines For Boating, Diving, Snorkeling Around Manatees.
Recovery From Brink of Extinction
The manatee in 2017 was reclassified from “endangered” status to “threatened” by the federal government, see the U.S. Fish and Wildlife Service (Southeast Region) news announcement on this action. Florida manatees have made a remarkable recovery from the brink of extinction, with reported estimates of only a few hundred back in the 1970s. Current population counts indicate a positive outcome of protections put in place and overall conservation efforts.
Next 100 Years, Long-term Trends
The future of manatees for the next century has been forecast, the findings of a study by the U.S. Geological Survey Geological Survey and Florida Fish and Wildlife Research Institute (released in March 2017). According to the study, “The probability of the Florida manatee population falling below 500 adults on either the Gulf or East coast within the next 100 years was estimated to be 0.42 percent” [i.e.less than one percent].
Best Place To See Florida Manatees?
A place created to protect the Florida manatee, the Crystal River National Wildlife Refuge, is one of the top spots to view manatees in the less murky waters of Florida’s clear springs on the state’s west coast. The best time to see Florida manatees congregating in the Crystal River is during winter months (Nov. – March), a time when hundreds are in close proximity. They are also attracted to artificially warm water, congregating in winter around power plants.
Want to Help?
Give an online donation at the Sea to Shore Alliance (www.sea2shore.org). Florida residents can help support Manatee research and conservation efforts by purchasing a specialty license plate (i.e. “tag”). Also find out more online about Georgia’s conservation efforts at Georgia DNR’s Nongame Conservation Section (www.georgiawildlife.com/conservation).