Manatees Dying in Record Numbers from Toxic Algal Bloom
By Elizabeth Fleming
2013 is shaping up to be a particularly deadly year for the endangered Florida manatee, whose population is estimated at around 5,000 animals. More than 460 dead manatees have been documented in the first three months of this year—an alarmingly high number. It has already topped the number of manatees that died all of last year. What’s going on here?
Well, among other threats, these aquatic mammals are experiencing injury and death in record numbers from exposure to a toxic algal bloom known as red tide in southwest Florida. Lee County has been particularly hard hit, followed by Charlotte County, Sarasota County and Collier County. Red tide is a naturally occurring event, but this outbreak has persisted since September 2012 and has killed as many as 240 manatees, a new record for red tide deaths in southwest Florida. Manatees are affected by red tide neurotoxins when they breathe, and even more so when they eat seagrass coated by the algae. The toxins cause seizures that can result in drowning when the animals cannot lift their snouts above the water to breathe.
According to the New York Times, experts are uncertain why this year’s algae bloom was so lengthy and toxic. Phosphorus runoff from fertilized farms and lawns may have contributed, because algae thrive on a phosphorus diet. The Caloosahatchee River, which runs through rural Florida farmland, empties into the ocean at Fort Myers.
Some manatees have been found alive but very ill, and have been transported to facilities where they receive around-the-clock care. This is the worst red tide outbreak since 1996, when 151 animals were killed by the algal bloom in the southwest part of the state. Even though the bloom is subsiding, manatees will continue to be affected for some time because toxins from the red tide have settled onto seagrass beds.
On the east coast of Florida, yet another threat is claiming manatee lives in the Indian River Lagoon in Brevard County. Nearly 100 manatees have died of an unknown cause, possibly from a different toxin, since July 2012. With most of Brevard’s seagrass eliminated due to a combination of factors (such as cold and drought that resulted in higher salinity) algal blooms known as “brown tide” have developed in the lagoon and impacted water clarity and seagrass growth. In some areas 99 percent of the seagrass has been lost. Without their staple food supply, manatees may be consuming macroalgae or other food sources that are making them ill and killing them.
The U.S. Fish and Wildlife Service is currently considering a proposal to downlist the manatee from “endangered” to “threatened.” Considering that the existing risks to manatees have not been alleviated and that little is known about emerging new threats, Defenders of Wildlife urges the Service to carefully incorporate these significant losses into their review and assessment of the status of the manatee population.
These large manatee die-offs are the latest struggle in a long history of challenges for the Florida manatee, which was one of the first species protected by the Endangered Species Act when it was enacted in 1973. The leading human-caused threat to manatees is collisions with watercraft. So far this year, 15 manatees have been killed by boats. We expect this number to rise substantially before the year is over, and especially during the summer months. Scientists believe that unless this cause of death is controlled, the manatee population will not recover.
To address this threat, Defenders of Wildlife has been instrumental in the creation of new manatee protection speed zones, sanctuaries and refuge areas. We supported the establishment of manatee speed zones in Tampa Bay and Flagler County, and the creation of the Kings Bay Manatee Refuge that made all but a small portion of the bay a slow-speed area. We advocate for improved enforcement of speed zones and comment on management plans for federal and state parks and refuges to ensure that they adequately address manatee protections.
An even greater, long-term threat is the loss of warm water habitat that manatees need to survive in winter. The deadliest year on record, 2010, saw 766 manatees killed, nearly 300 of them by an extended period of very cold weather. Because residential development has greatly reduced the natural warm water springs manatees need to stay warm, many of the animals aggregate in the warm-water outfalls at electric power plants on cold winter days. A large percentage of the manatee population could be lost in the future if aging plants are shut down.
Defenders of Wildlife is hard at work to protect manatee habitat. We petitioned the U.S. Fish and Wildlife Service to revise critical habitat for the Florida manatee, supported the acquisition of Three Sisters Spring for Crystal River National Wildlife Refuge, increased protections for manatees overwintering in Kings Bay and strengthened seagrass protections in Everglades National Park. We advocate for increased protection for natural springs, agency efforts to increase manatee access to springs and adoption by agencies and power companies of a warm-water contingency plan to help manatees transition from artificial to natural sites.
If you’re in Florida and you see a manatee in distress that may be suffering from red tide exposure or any other injury, call 1-888-404-3922 immediately. Be sure that your actions are not putting manatees at risk: refrain from pursuing, touching, feeding or watering manatees, and practice safe boating for the manatees’ sake and yours.
Visit EcoWatch’s BIODIVERSITY page for more related news on this topic.
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Kevin T. Smiley
When hurricanes and other extreme storms unleash downpours like Tropical Storm Beta has been doing in the South, the floodwater doesn't always stay within the government's flood risk zones.
New research suggests that nearly twice as many properties are at risk from a 100-year flood today than the Federal Emergency Management Agency's flood maps indicate.
Flooding Outside the Zones<p>About <a href="https://furmancenter.org/files/Floodplain_PopulationBrief_12DEC2017.pdf" target="_blank">15 million</a> Americans live in FEMA's current 100-year flood zones. The designation warns them that their properties face a 1% risk of flooding in any given year. They must obtain flood insurance if they want a federally ensured loan – insurance that helps them recover from flooding.</p><p>In Greater Houston, however, <a href="https://doi.org/10.1111/j.1539-6924.2012.01840.x" target="_blank">47% of claims</a> made to FEMA across three decades before Hurricane Harvey were outside of the 100-year flood zones. Harris County, recognizing that FEMA flood maps don't capture the full risk, now <a href="https://www.hcfcd.org/floodinsurance" target="_blank" rel="noopener noreferrer">recommends that every household</a> in Houston and the rest of the county have flood insurance.</p><p>New risk models point to a similar conclusion: Flood risk in these areas outstrips expectations in the current FEMA flood maps.</p><p>One of those models, from the <a href="https://firststreet.org/flood-lab/research/2020-national-flood-risk-assessment-highlights/" target="_blank">First Street Foundation</a>, estimates that the number of properties at risk in a 100-year storm is 1.7 times higher than the FEMA maps suggest. Other <a href="https://doi.org/10.1088/1748-9326/aaac65" target="_blank" rel="noopener noreferrer">researchers</a> find an even higher margin, with 2.6 to 3.1 times more people exposed to serious flooding in a 100-year storm than FEMA estimates.</p>
What FEMA’s Flood Maps Miss<p>Understanding why areas outside the 100-year flood zones are flooding more often than the FEMA maps suggest involves larger social and environmental issues. Three reasons stand out.</p><p>First, some places rely on relatively old FEMA maps that don't account for recent urbanization.</p><p>Urbanization matters because impervious surfaces – think pavement and buildings – are not effective sponges like natural landscapes can be. Moreover, the process for updating floodplain maps is locally variable and can take years to complete. Famously, New York City was updating its maps when Hurricane Sandy hit in 2012 but hadn't finished, meaning flood maps in effect <a href="https://projects.propublica.org/nyc-flood/" target="_blank">were from 1983</a>. FEMA is required to assess whether updates are needed every five years, but the <a href="https://www.fema.gov/cis/nation.html" target="_blank" rel="noopener noreferrer">majority of maps</a> <a href="https://www.oig.dhs.gov/sites/default/files/assets/2017/OIG-17-110-Sep17.pdf" target="_blank" rel="noopener noreferrer">are older</a>.</p><p>Second, binary thinking can lead people to an underaccounting of risk, and that can mean communities fail to take steps that could protect a neighborhood from flooding. The logic goes: if I'm not in the 100-year floodplain, then I'm not at risk. Risk perception <a href="https://doi.org/10.1088/1748-9326/ab195a" target="_blank" rel="noopener noreferrer">research</a> backs this up. FEMA-delineated flood zones are the major factor shaping flood mitigation behaviors.</p><p>Third, the era of climate change scuttles conventional assumptions.</p><p>As the planet warms, extreme storms are becoming <a href="https://nca2018.globalchange.gov/" target="_blank">more common and severe</a>. If greenhouse gas emissions continue to increase at a high rate, computer models suggest that the chances of a severe storm dropping 20 inches of rain on Texas in any given year will increase from about 1% at the end of the last century to 18% at the end of this one, a chance of <a href="https://doi.org/10.1073/pnas.1716222114" target="_blank" rel="noopener noreferrer">once every 5.5 years</a>. So far, <a href="https://www.rstreet.org/wp-content/uploads/2020/02/195.pdf" target="_blank" rel="noopener noreferrer">FEMA hasn't taken into account the impact climate change is having</a> on extreme weather and sea level rise.</p>
Racial Disparities in Flooding Outside the Zones<p>So, who is at risk?</p><p>Years of research and evidence from storms have highlighted social inequalities in areas with a high risk of flooding. But most local governments have less understanding of the social and demographic composition of communities that experience flood impacts outside of flood zones.</p><p>In analyzing the damage from Hurricane Harvey in the Houston area, I found that <a href="https://doi.org/10.1088/1748-9326/aba0fe" target="_blank">Black and Hispanic residents disproportionately experienced flooding</a> in areas beyond FEMA's 100-year flood zones.</p><p>With the majority of flooding from Hurricane Harvey occurring outside of 100-year flood zones, this meant that the overall impact of Harvey was racially unequal too.</p><p>Research into where flooding occurs in Baltimore, Chicago and Phoenix points to some of the potential causes. <a href="https://www.nap.edu/read/25381/chapter/4#16" target="_blank" rel="noopener noreferrer">In Baltimore and Chicago</a>, for example, aging storm and sewer infrastructure, poor construction and insufficient efforts to mitigate flooding are part of the flooding problem in some predominantly Black neighborhoods.</p>
What Can Be Done About It<p>Better accounting for those three reasons could substantively improve risk assessments and help cities prioritize infrastructure improvements and flood mitigation projects in these at-risk neighborhoods.</p><p>For example, First Street Foundation's risk maps account for <a href="https://firststreet.org/flood-lab/research/flood-model-methodology_overview/" target="_blank">climate change</a> and present <a href="https://floodfactor.com/" target="_blank" rel="noopener noreferrer">ratings</a> on a scale from 1 to 10. FEMA, which works with communities to update flood maps, is <a href="https://www.fema.gov/media-library-data/1521054297905-ca85d066dddb84c975b165db653c9049/TMAC_2017_Annual_Report_Final508(v8)_03-12-2018.pdf" target="_blank" rel="noopener noreferrer">exploring rating systems</a>. And the National Academies of Sciences, Engineering and Medicine recently <a href="https://www.nationalacademies.org/news/2019/03/new-report-calls-for-different-approaches-to-predict-and-understand-urban-flooding" target="_blank" rel="noopener noreferrer">called for a new generation of flood maps</a> that takes climate change into account.</p><p>Including recent urbanization in those assessments will matter too, especially in fast-growing cities like Houston, where <a href="https://authors.elsevier.com/a/1boBRyDvMFW6W" target="_blank" rel="noopener noreferrer">386 new square miles</a> of impervious surfaces were created in the last 20 years. That's greater than the land area of New York City. New construction in one area can also <a href="https://scalawagmagazine.org/2018/01/city-in-a-swamp-as-houston-booms-its-flood-problems-are-only-getting-worse/" target="_blank" rel="noopener noreferrer">impact older neighborhoods downhill</a> during a flood, as some Houston communities discovered in Hurricane Harvey.</p><p>Improving risk assessments is needed not just to better prepare communities for major flood events, but also to prevent racial inequalities – in housing and beyond – from <a href="https://www.npr.org/2019/03/05/688786177/how-federal-disaster-money-favors-the-rich" target="_blank" rel="noopener noreferrer">growing</a> after the unequal impacts of disasters.</p>
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