Phenology of marine turtle nesting revealed by statistical model of the nesting season

Marc Girondot,Stéphane Caut,Jean-Paul Briane,Elodie Guirlet,Ronald Wongsopawiro,Matthew H Godfrey,Philippe Rivalan,Vincent Hulin

doi:10.1186/1472-6785-6-11

Abstract

BackgroundMarine turtles deposit their eggs on tropical or subtropical beaches during discrete nesting seasons that span several months. The number and distribution of nests laid during a nesting season provide vital information on various aspects of marine turtle ecology and conservation.ResultsIn the case of leatherback sea turtles nesting in French Guiana, we developed a mathematical model to explore the phenology of their nesting season, derived from an incomplete nest count dataset. We detected 3 primary components in the nest distribution of leatherbacks: an overall shape that corresponds to the arrival and departure of leatherback females in the Guianas region, a sinusoidal pattern with a period of approximately 10 days that is related to physiological constraints of nesting female leatherbacks, and a sinusoidal pattern with a period of approximately 15 days that likely reflects the influence of spring high tides on nesting female turtles.ConclusionThe model proposed here offers a variety of uses for both marine turtles and also other taxa when individuals are observed in a particular location for only part of the year.

Highlights

Marine turtles deposit their eggs on tropical or subtropical beaches during discrete nesting seasons that span several months
The Akaike Information Content (AIC) of the 8 models describing the shape of the nesting season was lowest when the K1 parameter was fixed to 0
22 daily counts were missing at the end of the nesting season

Summary

Introduction

Marine turtles deposit their eggs on tropical or subtropical beaches during discrete nesting seasons that span several months. Many species migrate and are present at a particular geographic location during only part of the year [1,2]. This behavior often produces 'tidal-waves' in the density of individuals along the migration route [3] with a lower frequency signal at wintering or aestivating grounds where the animals tend to stay longer. The presence of auklets peaks in the morning and in the evening at some colonies [5] In this latter example, population estimates may vary depending (page number not for citation purposes)

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