2014 Florida Manatee Count 3rd Highest On Record

The Banana River with NASA's Vehicle Assembly Building at Kennedy Space Center in the background.                    Brevard Times / File photo.

UPDATE: The County Commission voted 4 to 1 to increase the stormwater fee from $36 to $52 for the next two years, followed by an increase to $64 in the third year.  A proposal to raise the minimum stormwater fee to $5 did not pass.  Commissioner Trudie Infantini was the sole no vote.

VIERA, Florida -- On the Brevard County Commission Agenda at 5:00 p.m. on Thursday, April 3, is a proposal to raise the stormwater fee assessed on properties in Brevard County from $36 to $64.  

The proposed sewer fee increase comes during the same year when there is also a proposal to increase fire fees. Later in 2014, voters will decide in November whether to add a half-cent sales tax for schools.


"Should we build a tourist welcome center at a cost of $3,000,000; pay the Washington Nationals $29,000,000 to stay; pay $6,500,000 toward the construction of a shopping mall/office building/movie theater or spend the money to reduce runoff to the lagoon?" Brevard County Commissioner Trudie Infantini wrote in an email.  "Prioritization is the problem in my opinion.  So I will NOT support taxing individuals more when we, as a Board, cannot prioritize the spending of funds we already have."

In a memo to Brevard County Commissioners, County Manager Howard Tipton wrote:

"Should the Board approve the proposed increase, these funds will be applied toward efforts to restore the Indian River Lagoon.  These funds will be applied using proven technologies and programs to provide results by reducing future pollution, removing existing pollution and sources of much; and restoring the ecosystem; all of which will be guided by the best available research."

But according to the Saint John's River Management District's Indian River Lagoon 2011 Superbloom Investigation, stormwater and wastewater discharges were unlikely causes for the algal superbloom:
 

"It was more surprising that the event even happened at all given the long-term drought conditions during the 2009 – 2011 period [and the] decreasing trend in treated wastewater discharges... drought means comparatively little rainfall-runoff...The other major external sources – atmospheric and groundwater – are similarly affected by rainfall and would be diminished during the same period. Therefore; notwithstanding some unreported nutrient-laden discharge, an internal flux of nutrients may be the primary mechanism that fueled the bloom. " (Emphasis added).

Background:

Two events marked the decimation of the Lagoon's environment.  First, there was the loss of over 60% of seagrass coverage from 2009 through 2012.  Second, there was the Indian River Lagoon Algae Superbloom that lasted from April 2011 through March 2012.   Both events were extraordinary because no events of that scale had ever been recorded in the Lagoon's history.  


Those extraordinary events were followed by an unusually high number of manatee deaths beginning in 2012 and continuing throughout 2013.  Unusually high dolphin and pelican deaths were also recorded during 2013.


Despite those events being historically extraordinary statistical outliers, many environmentalists blamed the Lagoon's demise on causes that have otherwise remained constant (or even dropped) such as fertilizers, sewage, muck, grass clippings, runoff, pet waste, and even global warming.  

But the strongest evidence against those particular human-related common causes was the geographical location of the start of the Superbloom in the northernmost portion of the Banana River that is bordered by sparse populations because the Kennedy Space Center, Cape Canaveral Air Force Station, Canaveral National Seashore, and the Merritt Island National Wildlife Refuge make up most of that area's landmass as shown in the above graphic.

In fact, a 2003 scientific research paper titled Impacts of Reduced Salinity on Seagrasses in Indian River Lagoon published in the Journal of Phycology, an International Journal of Algal Research, stated that the northern Banana River is "an area of IRL considered the least anthropogenically impacted."  That's scientific jargon meaning that humans have little impact on that area of the Indian River Lagoon.

Graphic Credit: SJRMD - Federal Lands coloration added by Brevard Times

Ignoring the 1,500 Pound Sea Cows in the Lagoon

Graphic Credit: SJRMD.  Tropical Storm Fay, Florida Fish and Wildlife Manatee Count, Coldest Winter,  and Superbloom added by Brevard Times

As the above graphic shows, there appears to be an inverse relationship with the manatee population counts and seagrass acreage whenever the manatee count exceeds around 1,700 on Florida's East Coast (the Florida Fish and Wildlife Commission cautions that the published manatee survey count provides a minimum count of manatees, but it does not provide an accurate population estimate).

According to a research study performed by the University of Florida and the U.S. Geological Survey in 2012,  the record-breaking manatee population has grown so much in the last decade that they may be reclassified by wildlife management officials from endangered to  threatened.

 

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 U.S. Fish and Wildlife 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.  Based on those consumption rates, an average manatee can consume and/or destroy around 3 acres of seagrass a year, depending on the density of the seagrass per acre.

Has a population rebound of an endangered species ever caused a collapse in seagrass beds before?

Many scientists believe that the rebound in endangered sea turtle populations caused localized declines and/or collapses of large seagrass beds in the 1990's and 2000's.  In a scientific publication entitled Effects of excluding sea turtle herbivores from a seagrass bed: Overgrazing may have led to loss of seagrass meadows in Bermuda, research suggests that:

It is likely that the removal of the photosynthetic potential of leaves by grazing sea turtles decreased the production and storage of photosynthate in the seagrasses, slowing their growth and reducing the ability of the seagrasses to recover from unfavorable environmental conditions. This makes the effects on seagrasses of the grazing by sea turtles similar to the effects of severe light reduction. (Emphasis added). 




Could manatees have consumed all the seagrass that disappeared from 2009-2011? 



Even if 2,000 manatees consumed and/or destroyed 3 acres of seagrass per year, that would only amount to 18,000 acres of seagrass (2000 manatees x 3 acres x 3 years).  So manatee consumption alone would not have accounted for the total loss of approximately 30,000 acres of seagrass during 2009-2011.  Additionally, the amount of seagrass consumed by manatees should have been mitigated by the re-growth of seagrass over those three years.       


However, just like in the sea turtle study, the record-breaking manatee population and corresponding increased seagrass consumption could have put enough pressure on the seagrass to reduce its ability to recover from unfavorable environmental conditions such as decreased salinity in the Lagoon from record-breaking rainfall caused by Tropical Storm Fay in 2008, the coldest winter on record in 2009-2010, drought conditions during 2009-2011 that caused land vegetation to die and decompose in the Lagoon, and the Superbloom during 2011-2012.   



The additional pressure put on on the seagrass by an increased manatee population coupled by weather extremes could have caused a tipping point where less seagrass meant that other herbivores, with less grazing areas, put additional pressure on the remaining seagrass which started the spiraling loss of over 30,000 acres of seagrass before the Superbloom of March 2011.   


Also, seagrass absorbs and stores nitrogen and phosphorous.  When manatees consume seagrass, they then discharge that stored nitrogen and phosphorous as waste which becomes free nutrients in the Lagoon.  The waste from increased manatee population could be the "internal flux of nutrients" that the Superbloom Investigation hypothesized.  Manatee waste, disturbed by severe weather in late March 2011, could also explain why the Superbloom occurred near Kennedy Space Center where there are sparse populations and military-restricted waterways.     



The manatees' population comeback resulted in another extraordinary event in recent years.  Residents in Vero Beach witnessed the full extent of the sea cows' voracious appetites' end product in 2009 when a mile-long stretch of manatee fecal matter closed area beaches.  

“I’ve never seen anything like it, and I’ve lived along beaches all my life,” beach-goer Bill Becker told TCPalm. “It was disgusting, but mystifying. It looked like Great Dane poop all along the beach.” 

The manatee population rebound has also resulted in a lack of genetic diversity where inbreeding could become a problem, according to UF researchers. 


SIMILAR STORIES:

2014 Florida Manatee Count 3rd Highest On Record

Infantini: Brevard County Storm Water and Fire Assessments Could Double