For a process known as histology, MMPL biologists collect
numerous tissue samples during necropsies of fresh carcasses.
Histology is a useful tool for identifying pathologies and
diagnosing causes of death.
Scientists at the Marine Mammal
Pathobiology Laboratory (MMPL) perform necropsies (non-human
autopsies) on manatees and, as necessary, on a variety of other
marine animals. During necropsy of fresh carcasses, tissue samples
are cut from a variety of organs and placed in a preservative so
they may be used for histology: the study of the structure of
organic tissues. The preservative used in this process stops
decomposition and hardens the tissues. Tissues are trimmed further
and then treated with stains to help emphasize cellular components.
The stained sections are embedded in paraffin (wax) and sliced
extremely thin (to 10 micrometers). These sections are applied to a
glass slide so they can be examined under a light microscope. In
general, MMPL scientists conduct histology for four reasons:
- Track or Monitor Changes-In addition to
determining "normal" tissue conditions, histology allows scientists
to recognize tissue changes over time.
- Observe Pathologies-Scientists are still
learning about the pathologies (the conditions and processes of
diseases) in manatees and other species. Many of these pathologies
can be identified microscopically.
- Cause of Death-Violent causes of death, such
as impact from watercraft or boat propellers, may be obvious in
necropsy. However, other causes of death may not be readily
apparent without histological information.
- Archives-Historical information is kept
through storing preserved tissues for later use, also known as
tissue banking. This archiving process will allow scientists
studying manatees in the future to compare their research with data
from the past. Tissue banking gives scientists the potential to
study much larger groups of animals over longer periods of
Fresh carcasses provide the most useful histological
information. Unfortunately, after death, manatees and other animals
and plants decay quickly in Florida's warm, humid climate. As
tissues and cells degrade, less histological information can be
retrieved from them. The histological information gleaned from each
sampled carcass provides researchers with additional information
about both individual animals and the species as a whole. This
effort is vital to manatee research, so whenever possible,
researchers include histology collection as part of necropsies.
While every manatee death is a tremendous loss, each manatee
carcass provides a new opportunity to learn information that may
allow scientists to help conserve the manatees that are still
living. The organized collection of histological data and other
samples allows researchers access to additional information that
may ultimately lead to improved conservation of this endangered