Observation Of A Distributional Mechanism: Implications In Support Of A Kemp's Ridley Pelagic Nursery Hypothesis

Abstract

The Gulf of Mexico contains the only known breeding population of Kemp's Ridley Sea Turtles (Lepidochelys kempi); the turtles come ashore to nest along a seventeen mile stretch of coastline near the town of Rancho Nuevo in the Tamaulipas state of Mexico. Once the hatchlings leave the nests and enter the water they are not seen again until they migrate into near shore waters as yearlings. Dr. Sneed Collard of the University of West Florida proposed that during this "lost year" the hatchlings could survive as passive drifters within a Gulf of Mexico pelagic nursery. Two Argos-reported surface drifter trajectories. are used to support this theory by providing evidence that a passively drifting object can remain within the Gulf of Mexico for periods in excess of a year and are further used to demonstrate an example of the mechanism by which drifting objects can be transported from one current regime to another. Field observations discussed herein give reasonable evidence that there are episodic physical features in the Gulf interpretable as chaotic transporters of both active swimmers and passive drifters. Case studies of these transport processes shows them capable of providing surface water trajectories consistent with Dr. Collard's pelagic nursery hypothesis.