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Publication Date

Spring 2014

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)

Department

Moss Landing Marine Laboratories

Advisor

James T. Harvey

Keywords

Dermochelys coriacea, Foraging region, Nutritional stress, Papua Barat, Reproductive output, Stable isotopes

Subject Areas

Ecology

Abstract

Western Pacific leatherback turtles migrate to geographically distinct foraging regions. Turtles that nest between April and September in Bird's Head nesting beaches in Papua Barat, Indonesia migrate to the South China Sea (SCS), North Pacific Transition Zone (NPTZ), and Northeast Pacific (NEP). The primary objective of this study was to compare body size and reproduction of turtles that foraged in these distinct regions, as inferred by their skin stable isotope values. Skin samples and reproductive output data were collected during the 2010 and 2011 nesting seasons. Foraging group composition of the nesting population varied between the two seasons. Leatherbacks that foraged in the NEP had greater body size and more years between consecutive nesting seasons than did others that foraged in the SCS and NPTZ. Leatherbacks that foraged in the NPTZ laid more clutches and had fewer years between consecutive nesting seasons than did others that foraged in the SCS and NEP. Within-population variation in body size, reproductive output, and breeding periodicity likely reflect variation in energetic gains and returns associated with each foraging region. To examine relationships between nitrogen and carbon of skin and fasting duration, two skin samples were collected from 53 turtles during separate nesting emergences in 2010. Skin stable nitrogen values increased with sampling interval but stable carbon did not, indicating that stable nitrogen values can be used to detect nutritional stress in fasting leatherback turtles.

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