Science Advisory Report  2012/036

Using Satellite Tracking Data to Define Important Habitat for Leatherback Turtles in Atlantic Canada

Summary

• The leatherback turtle is the most widely distributed and largest of all marine turtles, and undertakes annual migrations to Atlantic Canadian waters to forage.
• Satellite telemetry data from 70 leatherbacks tracked in Atlantic Canadian waters were used to identify important habitat for the species.
• Satellite telemetry data serve as a proxy for direct sampling of important habitat, under the explicit assumption that the relative probability of leatherbacks exhibiting residency behaviour is positively correlated with foraging habitat quality. In the current context, residency denotes turtles that are likely engaged in area-restricted search while present in Atlantic Canadian waters and does not imply that turtles are present year-round.
• A state-space model was used to estimate the most probable locations for each turtle at regular time intervals, and to infer the behavioural state (resident or transient) that turtles were engaged in at each estimated location.
• The relative probability of residency (i.e., being in the resident behavioural state) associated with each turtle location was mapped to visualize the spatial distribution of the relative probability of residency for all leatherback turtles tracked in Atlantic Canadian waters. A relative probability of 0.4 or greater was selected to illustrate a strong likelihood of leatherback turtles being present and engaging in intensive prey searching or foraging behaviour.
• Three primary areas of important habitat are identified: (1) GB - waters east and southeast of Georges Bank, including the Northeast Channel near the southwestern boundary of the Canadian Exclusive Economic Zone (EEZ); (2) GSL - the southeastern Gulf of St. Lawrence and waters off eastern Cape Breton Island, including Sydney Bight, the Cabot Strait, portions of the Magdalen Shallows and adjacent portions of the Laurentian Channel; and (3) PB - waters south and east of the Burin Peninsula, Newfoundland, including parts of Placentia Bay.  
• These areas are likely important for leatherback turtles because they serve as foraging habitat.
• The movements of satellite tagged turtles were widely distributed throughout Atlantic Canadian waters, with turtles sampling habitat across a broad area (most of the Atlantic Canadian EEZ). Peak use of the important habitat areas occurs in summer and autumn.
• It is expected that review of important habitat areas will be updated when new information (e.g., prey distribution, prey concentration, turtle behaviour) becomes available.

This Science Advisory Report is from the February 29 to March 1, 2012, review of Leatherback Sea Turtle Part 1: Using Satellite Tracking Data to Define Important Habitat. Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

Complete document (PDF, 1010 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.