Article Review:

Hierarchical State-Space Estimation of Leatherback Turtle Navigation Ability

Author: Joanna Mills Flemming

Using Argos satellite tracking systems, researchers tracked 14 leatherback turtles (7 male and 7 female) that were headed south from Nova Scotia during their migrations period. They were tracked in order to observe their navigation tendencies during migration. Researchers wanted to see if there was a tendency for turtles to “recalculate” their position after they are off their migratory path to compensate for large diversions.

One of the factors that were observed with each sea turtle was its “circle of confusion.” This is the radius where the turtle is not able to accurately determine its position or orientation. Results show that the average circle of confusion for all turtles was 96.2km while it was 98.7 for males and 75.3 for females. The results for sex were relatively similar due to the fact that the male results were somewhat skewed by one individual.

It is hypothesized that the Leatherback sea turtles are able to determine their location by using several navigational cues. In order to properly navigate, their circle of navigation must be slightly smaller than the range of their other navigational cues.

Areas of research that could be refined include taking into account of currents and other migratory factors that would influence the path of sea turtles. These factors could lead to biased results primarily pertaining to the circle of confusion. Researchers say that with increased influence in ocean currents, estimates of the circle of confusion could be higher than the actual circle/area. Additionally, some of the assumptions made in this article were based on other research, not all of which was performed on full migratory patterns. Some of the data that was used to compare results consisted of research using “manipulated” animals or research performed in a laboratory. Research could be considered more thorough if there was data from full migratory patterns to compare with. 

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0014245

1. Department of Mathematics & Statistics, Dalhousie University, Halifax, Canada, 2 Department of Biology, Dalhousie University, Halifax, Canada