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How numbers of nesting sea turtles can be overestimated by nearly a factor of two / Nicole Esteban; Jeanne A. Mortimer; Graeme C. Hays

Proceedings of the Royal Society B: Biological Sciences, Volume: 284, Issue: 1849, Start page: 20162581

Swansea University Author: Esteban, Nicole

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DOI (Published version): 10.1098/rspb.2016.2581

Abstract

Estimating the absolute number of individuals in populations and their fecundity is central to understanding the ecosystem role of species and their population dynamics as well as allowing informed conservation management for endangered species. Estimates of abundance and fecundity are often difficu...

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Published in: Proceedings of the Royal Society B: Biological Sciences
ISSN: 0962-8452 1471-2954
Published: 2017
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URI: https://cronfa.swan.ac.uk/Record/cronfa31973
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Abstract: Estimating the absolute number of individuals in populations and their fecundity is central to understanding the ecosystem role of species and their population dynamics as well as allowing informed conservation management for endangered species. Estimates of abundance and fecundity are often difficult to obtain for rare or cryptic species. Yet, in addition, here we show for a charismatic group, sea turtles, that are neither cryptic nor rare and whose nesting is easy to observe, that the traditional approach of direct observations of nesting has likely led to a gross overestimation of the number of individuals in populations and underestimation of their fecundity. We use high resolution GPS satellite tags to track female green turtles throughout their nesting season in the Chagos Archipelago (Indian Ocean) and assess when and where they nested. For individual turtles, nest locations were often spread over several 10s of km of coastline. Assessed by satellite observations, a mean of 6.0 clutches (range 2-9, SD=2.2) was laid by individuals, about twice as many as previously assumed, a finding also reported in other species and ocean basins. Taken together, these findings suggest that often the actual number of nesting turtles may be almost 50% less than previously assumed.
Keywords: Chagos, Chelonia, Argos, Fastloc-GPS, clutch frequency, critically endangered
College: College of Science
Issue: 1849
Start Page: 20162581