Using Programming Languages and Geographic Information System to Determine Spatial and Temporal Variability in a Green Turtle Foraging Population on Liuchiu Island, Taiwan.

Abstract

Facial photo identification (ID) has proven to be a non-invasive method for identifying individual wild animals, and in recent years it has been effective on megafauna such as sea turtles. However, when processing hundreds of photos over a long period of time, variation in facial scale patterns makes identifying individuals complicated. This means that there is a high possibility that the individual is misidentified, which results in incorrectly determining population sizes. This study used the programming languages Python and SQL to determine green turtle foraging population size in the nearshore waters of a coral island, Liuchiu Island, from 2011 to 2017. The programs determined that the foraging population was 432 turtles, approximately 90% of which resided there one year or less and selected only one foraging site. Those that stayed for more than two years selected two foraging sites. Less than 3% stayed throughout the 7 years. The core residence area was from Beauty Cave to Vase Rock. This study found that the nearshore waters of Liuchiu Island are a temporary development/foraging site for immature green turtles. This is the first study to use Python analysis to determine a foraging sea turtle population in the field.