Sunday, December 04, 2011

Her name was Griselda...

Photo by Matthew Beck
Her name was Griselda.  First documented as an adult in Crystal River in 1977, Griselda had given birth to at least 12 calves.  Unfortunately, I only saw her laying on the cold stainless steel necropsy table.   I had taken 3 international colleagues to witness a necropsy at the pathology lab on the campus of Eckerd College.  We were all in Tampa for 19th Biennial Meetings of the Society for Marine Mammalogy.

Griselda, an extremely successful mother manatee is gone forever from the Florida manatee population due to a boat strike that broke her shoulder blade and dislocated her 4th rib on the left side--rupturing her aorta.  She died of internal bleeding, probably within an hour of being hit.  Griselda was lactating, which means there is an orphan calf out there somewhere...hopefully old enough to survive on its own.

Unfortunately, this is the not the first time I've witnessed this cause of death.  One of the known manatees in Belize died in exactly the same way a few years ago, also leaving an orphaned calf.   This type of injury often leaves no external marks, no propeller cuts, and no bruising -- only a necropsy can determine the cause of death in such a case.  It occurs when the foot of an engine strikes the manatee on the back resulting in acute force at the point where the ribs attach to the spine.  In both cases that I've witnessed, the 4th left rib was subluxed (dislocated downward) piercing a large vein or artery near the heart.  As the heart continues to beat, blood is pumped out of the circulatory system into the muscles or body cavity.  Death generally comes within minutes.

Manatees have evolved over millions of years to be extremely successful in shallow aquatic environments.  But, they are not well designed for competition with motorized boats, which have only been around a few years.  We humans, as operators of these powerful machines, must take responsibility for preventing such deadly encounters.  Download this brochure and learn how to prevent tragic mortality events in Florida:

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