Did you know that it
is currently not possible to accurately age a living turtle? Yet successful
conservation of marine turtles relies on having the best possible understanding
of habitat use and complete life history. Therefore, age-at-size estimates are
used to construct population structure and abundance models for management (Crouse et al. 1987, Heppell et al. 2003).
Hamann et al. (2010) identified the need
to “develop methods to accurately age individual turtles, determine a
population’s (or species’) mean age-at-maturity, and define age-based
demography” as one of the top 20 global research priorities for marine turtle
conservation and management. This report also concluded that researchers must
identify the “parameters [that] influence the biogeography of sea turtles in
the oceanic realm” and resolve the “demography of turtles in the oceanic stage,
including the duration of the oceanic juvenile stages”.
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| Source: http://seaturtlefoundation.com/ |
Determining
age of turtles and life stage-duration through my research will address this
priority to improve the population ecology and conservation of sea turtles. In
addition, each distinct life stage of marine turtles experiences different
types and intensities of threats. For example, a small juvenile turtle living
out in the open ocean is exposed to threats (i.e. large industrial fishing
fleets, natural oceanic predators, ghost-fishing nets & etc.) that are very
different from the types of threats that a much large turtle will be faced with
while living in a coastal area or lagoon (i.e. boat traffic, coastal pollution,
smaller scale fishing efforts & etc.).
Assessing
the variability of these impacts at each stage and habitat is difficult when
stage duration is uncertain, making it a challenge to prioritize and implement
protection measures to mitigate these impacts. By more accurately determining
the duration of each life stage (i.e. how many years a turtle is in each stage)
the full impact of particular sources of mortality on the overall population
can be prioritized and more effectively managed.
My
research will uses skeletochronology- a method to age dead turtles, together
with other emerging techniques to generate age-based demographic parameters,
including stage duration, for two populations of marine turtles in the Pacific.
This research will contribute important information to marine turtle managers
by directly addressing two of the top research priorities identified for marine
turtle conservation.
Next blog entry: Techniques used to address these questions - learn more about how skeletochronology and stable isotope analysis can determine the age and past locations of sea turtles.
And if you have not already - please see the previous entry, "A call to help: Support Community Based Sea Turtle Conservation & UCSD Research" and watch the video to learn more about my research and how YOU can help out!
Some images in video obtained under NMFS Permit #1591
References:
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