Smaller turtles are nesting on Florida beaches
The findings give clues to the health and status of the threatened
species
Date:
July 8, 2021
Source:
University of Central Florida
Summary:
A new study indicates that smaller loggerhead and green sea
turtles are nesting on Florida beaches than in the past; however,
researchers aren't sure why. The findings give clues to the status
of the turtles, which is important to researchers who are monitoring
the population health of the threatened species.
FULL STORY ==========================================================================
A new University of Central Florida study indicates that smaller
loggerhead and green sea turtles are nesting on Florida beaches than in
the past; however, researchers aren't sure why.
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The findings, published this month in the journal Ecosphere, give clues
to the status of the turtles, which is important to researchers who are monitoring the population health of the threatened species.
Central Florida's Atlantic coastline hosts about one-third of all green
turtle nests in the state and is one of the most important nesting areas
in the world for loggerheads.
Sea turtles are important as iconic symbols of conservation in Florida
and for the role they play in maintaining a healthy ocean ecosystem.
The reason for the appearance of smaller nesting turtles is still a
mystery though, says Katrina Phillips, the study's lead author and a
doctoral candidate in UCF's Department of Biology.
"It might be that juvenile turtles are growing more slowly because they
are having a harder time finding food as a result of habitat degradation
or competition from other turtles," Phillips says. "Or smaller turtles
may also be new recruits to the population as a result of successful sea
turtle conservation efforts. We don't know why we're seeing more small
turtles nesting." The researchers made the discovery by comparing shell
length of nearly 10,000 nesting female loggerheads and more than 3,000
nesting female green turtles.
The measurements were collected by UCF's Marine Turtle Research Group
over the course of a 37-year period, from 1982 to 2019.
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The nesting turtles were observed in the Brevard County portion of
the Archie Carr National Wildlife Refuge. Age is not recorded or known
because it requires examining a cross-section of the turtle's leg bone,
which would require invasively sampling the turtle, and even then,
at best, age would be estimated.
The researchers found that the average size of nesting loggerheads
decreased by nearly 1 inch and the average size of nesting green sea
turtles decreased by more than 1.5 inches since 1982.
In addition to raising questions about why the turtles are smaller,
the findings also mean that when estimating female sea turtle maturity
based on size, researchers and management agencies will need to consider smaller turtles in their estimates.
"The numbers we provide for the minimum size range of mature females will
help other groups who study turtles in the water, where it's not clear if
they are mature or not, better estimate which of theirs are juveniles,"
she says.
The extensive study was made possible by the long-time work of UCF's
Marine Sea Turtle Research Group, the researcher says.
"Many nesting beach projects take these measurements, but the UCF project
is unique because of how long it's been going on and how many turtles
come ashore to nest here," Phillips says. "Florida gets more loggerhead
nests than anywhere else in the world, and the green turtle nest numbers
are rising." The monitoring project was started in 1982 by UCF Professor Emeritus and Pegasus Professor of Biology Llewellyn "Doc" Ehrhart.
Phillips says the UCF Marine Turtle Research Group will continue
monitoring the nesting sites, which will allow researchers to assess if
the trends continue or change.
========================================================================== Story Source: Materials provided by
University_of_Central_Florida. Original written by Robert Wells. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Katrina F. Phillips, Gustavo D. Stahelin, Ryan M. Chabot,
Katherine L.
Mansfield. Long‐term trends in marine turtle size at maturity
at an important Atlantic rookery. Ecosphere, 2021; 12 (7) DOI:
10.1002/ ecs2.3631 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2021/07/210708135408.htm
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