Nature
PUBLISHED
Florida has passed a grim milestone in 2021, having seen more manatee deaths in the first six months of 2021 than in any other year on record. Between January 1 to July 2, 2021, the Florida Fish & Wildlife Conservation Commission (FFWCC) has clocked 841 manatee deaths. The previous record was reported in 2013 when an outbreak of red tide – an algal bloom that can be deadly to marine wildlife – is thought to have contributed to the deaths of 830 manatees.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.While boat strikes are a considerable threat to manatees, having killed at least 63 this year according to a report from NPR, it’s thought that starvation has played a bigger role in the record-breaking mortality event. TCPalm reports that the majority of manatee death reports come from the Indian River Lagoon and its surrounding areas. Exactly why this area appears to be so deadly for these marine mammals isn’t yet clear, but some suspect it’s the result of contaminants destroying vital food sources.
“Unprecedented manatee mortality due to starvation was documented on the Atlantic coast this past winter and spring,” said the FFWCC, reported by the Guardian. “Most deaths occurred during the colder months when manatees migrated to and through the Indian River Lagoon, where the majority of seagrass has died off.”
Exactly what’s to blame for the destruction of seagrass could be a combination of factors, but algal blooms are once again a suspect. TCPalm reports that 16 environmental groups have banded together to form a coalition set on addressing the ecological crisis they believe to be unfolding in the Indian River Lagoon. In a letter to Governor Ron DeSantis, they urge that contaminants have pushed the ecosystem beyond a condition that can support marine life.
"The evidence is overwhelming and indisputable," read the letter, "that the Indian River Lagoon, one of the most biodiverse estuaries in North America, has become an unhealthy, algae-dominated ecosystem."
Algal blooms can be triggered when certain chemicals are released into the water, most often from human origin. Fertilizers are a common culprit, leaking from the land into waterways where they trigger a bloom that can sap the aquatic ecosystem of oxygen, killing plants and animals through a process known as eutrophication. Chemical contaminants can also affect wildlife through changing their behavior, as was demonstrated by the recent discoveries as to what antidepressants and methamphetamine can do to crayfish and trout.
