FWRI researchers are working on the mystery surrounding the first
years of a sea turtle's life. Although most of this "lost years"
period is spent in the open ocean far from land, young turtles are
observed in the Gulf Stream off Florida's east coast.
One of the least understood stages in the life of a
sea turtle is the pelagic phase, in which sea turtle hatchlings
swim into the open part of the ocean and spend the first years of
their life growing and developing. Called the "lost years," this
period actually lasts close to a decade in some species.
In a paper published in 2001,
FWRI research scientist Blair Witherington wrote about his work
observing and capturing neonate loggerheads in their habitat.
During 18 trips off the coast of Cape Canaveral, Florida,
Witherington followed the western edge of the Gulf Stream. The
following is taken directly from his report:
After the initial physical
oceanographic measurements were made, timed searches for turtles
were conducted by observers on the bow of the research vessel
(elevation was approximately 3 m above the surface) as it moved at
idle speed (approximately 2.5 knots) through the center of each
downwelling line. When a turtle was observed, the observer noted
the time of the observation, and the geographic position, species,
and behavior of the turtle. Observed turtles fell into four
- Turtles observed but not captured (n = 49). Data from these
turtles were used in addition to data from captured turtles to
calculate catch-per-unit-effort and species frequency.
- Turtles captured by dip net and released (n = 175). In addition
to gathering time, position, and species data, researchers weighed
these turtles with a spring scale, measured them for straight-line
carapace length (SCL, nuchal to pygal tip), and examined their
mouths for the presence of tar.
- Turtles captured with a habitat sampler, lavaged, and released
(n = 66). This capture technique was used to collect turtles along
with nearby floating material. These turtles were weighed,
measured, and examined as in (2) and were given gastric-esophageal
lavages to sample recently ingested items.
- Turtles found dead and collected (n = 3). These turtles were
weighed, measured, and examined as in (2) and were necropsied so
that gut contents could be examined.
All captured turtles were marked with a red grease pencil to
identify the turtle should it be recaptured (none were recaptured).
Turtles were released into habitat similar to their capture site
within 2 hours of their capture.
Sargassum fragments and seagrasses were the most
common among the ingested plants, with small, slow-moving animals
also in their diets. Post-hatchling loggerheads were found to be
low-energy, float-and-wait foragers, living both within and outside
downwelling lines. In his paper, Witherington also discusses the
amount of tar and plastics found in the turtle's stomachs when the
lavages were performed. (See "Tar and
Trash Invading Sea Turtle Habitats")
From "Ecology of neonate loggerhead turtles inhabiting lines of
downwelling near a Gulf Stream front." B.E. Witherington.
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