MIAMI, Florida – The U.S. Fish and Wildlife Service (FWS) announced on Thursday that the West Indian manatee is proposed to be downlisted from endangered to threatened status under the Endangered Species Act (ESA).
The minimum known manatee population is estimated to be at least 13,000, with more than 6,300 in Florida. When aerial surveys began in 1991, there were only an estimated 1,267 manatees in Florida, meaning that over the last 25 years there’s been a 500 percent increase in the species population in the Sunshine State.
The ESA defines an endangered species as one currently in danger of extinction throughout all or a significant portion of its range, and a threatened species as one that is likely to become endangered within the foreseeable future. FWS proposes that the West Indian manatee no longer falls within the ESA’s definition of endangered and should be reclassified as threatened after its review of the best scientific and commercial information available, including analyses of threats and populations.
“The manatee’s recovery is incredibly encouraging and a great testament to the conservation actions of many,” said Cindy Dohner, the FWS’s Southeast Regional Director in conjunction with an event at the Miami Seaquarium to announce the proposal.
In 2012, wildlife management officials recommended changing the status of manatees from endangered to threatened. But FWS did not act on that recommendation which prompted a lawsuit in 2014 from the Pacific Legal Foundation (PLF).
The proposal to downlist the manatee to threatened will not affect federal protections currently afforded by the ESA. The manatee also remains protected under the Marine Mammal Protection Act. These protections by FWS, the Florida Fish and Wildlife Commission, the Commonwealth of Puerto Rico, other state and federal agencies, and industries, resulted in the establishment of over 50 manatee protection areas, retrofitted water control structures, and power companies working cooperatively with federal and state conservation managers to address warm water outflows at wintering manatee congregation sites.
On Florida's East Coast, the manatee count has more than doubled in just the last eight years from 1,414 in 2007 to 3,333 in 2015, according to the Florida Fish and Wildlife Commission's annual survey.
Many waterfront property owners, boaters, and anglers on Florida's Space Coast blame the effect of the increased manatee population for the Indian River Lagoon's plight, especially when it comes to the inability of seagrass to regrow after the 2011-2012 Superbloom die off.
That's because an 800 to 1,200 pound adult sea cow can eat up 10% to 15% of its body weight daily in aquatic vegetation which mostly consists of seagrass. According to a FWS Manatee Recovery Plan, manatees sometime graze on seagrass which leaves the possibility for regrowth - but manatees also "root" seagrass - meaning the entire plant is pulled and the underwater sediment is disturbed.
In addition to food for manatees, seagrass supports the food web in the Indian River Lagoon which includes juvenile fish, sea turtles, dolphins, the American Bald Eagle, migratory birds, and other threatened or endangered species.
For the fist time in the decades-long debate between manatee activists and the boating community, the Florida Department of Environmental Protection (FDEP) acknowledged that the increased manatee population does have an effect on nutrient load and seagrass loss in the Indian River Lagoon following a Brevard Times investigation in 2014.
"At the time the seagrass TMDLs were developed [in 2009], manatees were not considered as major nutrient contributors to the Indian River Lagoon because not all the data needed to quantify the manatee nutrient contribution were available. It is worth noting that manatees have been part of the Indian River Lagoon ecosystem for a long time," FDEP stated in an email to Brevard Times.
"Based on the Department’s Nutrient and Dissolved Oxygen TMDLs for the Indian River Lagoon and Banana River Lagoon report (FDEP, 2009), the long-term annual average TN [Total Nitrogen] and TP [Total Phosphorous] loads entering the Indian River Lagoon system are about 1511 tons and 216 tons, respectively. The 25 to 109 tons of TN and 2 to 7 tons of TP contributed by manatees only account for about 1.7% to 6.7% of TN loads and 0.7% to 3.0% of TP loads entering the Indian River Lagoon system."
Photo credit: FWC