New insights on sea turtle behaviour during the 'lost years'

Area of Science:

• Marine Biology
• Conservation Science
• Ecology

Background:

• The early life stage of marine turtles, known as the 'lost years,' is poorly understood due to challenges in offshore study.
• Traditional assumptions suggest this stage occurs exclusively in oceanic habitats.

Purpose of the Study:

• To investigate the movement patterns and habitat use of juvenile marine turtles during their 'lost years.'
• To challenge and redefine the traditional understanding of the 'oceanic stage' in marine turtle life history.

Main Methods:

• Satellite tracking of 114 juvenile marine turtles (green, Kemp's ridley, loggerhead, hawksbill) in the Gulf of Mexico (2011-2022).
• Analysis of turtle movements in relation to oceanic (>200 m depth) and neritic (<200 m depth) waters.
• Comparison of turtle movements with oceanographic surface drifters.

Main Results:

• Tracked turtles frequently moved between oceanic and neritic zones, contradicting the exclusive oceanic habitat assumption.
• Sea turtle movements were not solely dictated by ocean currents, differing from surface drifters.
• The West Florida Shelf was identified as a high-use area, especially for green turtles and Kemp's ridleys.

Conclusions:

• The 'oceanic stage' should be redefined as a 'dispersal stage' to encompass observed habitat plasticity.
• The northeastern Gulf of Mexico is a critical habitat for conservation of threatened turtle species.
• Understanding juvenile marine turtle movements is vital for effective conservation strategies.