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Publication
Potential refuges for male production in loggerhead turtles within the northeast atlantic subpopulation
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Abstract(s)
The variation in sand temperature between beaches is an important factor
in sex determination in sea turtles. Rising temperatures due to climate change can cause
a female biased sex ratio in hatchlings. The importance of identifying microhabitats,
which have potential to produce hatchlings with balanced sex ratio should be a global
priority in sea turtle conservation programmes. We evaluated the variation in nesting sand
temperature between beaches and years at the maximum nesting depth (55cm) in an
important nesting colony of loggerhead turtles ( Caretta caretta ) on the Maio i sland, Ca b o
Verde. The air as well as sand temperatures were monitored on three beaches with
different sand colours (light, dark and mixed) during the breeding season of 2020, 2021
and 2022. The light sandy beach was cooler and recorded temperatures that favoured the
production of male hatchling s at the beginning and end of the nestin g season s . The
temperatures of dark and mixed sands were highly biased towards female hatchlings,
reaching lethal levels for embryos. However, in short periods of heavy rain and flooding,
the temperatures tend towards males in these types of sand . The obse rvations thus reveal
that there are few thermal microhabitats in this colony that are favourable to production
of male hatchlings , located at the extremes of nesting periods and during extreme climate
fluctuations.
Description
Keywords
Incubation substrate Air and sand temperature Sex ratio Conservation Sea turtles Loggerhead turtles (caretta caretta) Maio island Cabo Verde