Publications

Animal-borne video reveals atypical behaviour in provisioned green turtles : A global perspective of a widespread tourist activity

Smulders, Fee O.H.; O'Shea, Owen R.; Christianen, Marjolijn J.A.

Summary

Feeding wildlife as a tourist activity is a growing industry around the world. However, providing alternative food sources can affect wildlife ecology and behaviour. In this study, we combined animal-borne cameras on five sub-adult green turtles (Chelonia mydas) from the Bahamas with a global review to directly assess impacts of provisioning on the behaviour of an endangered marine species for the first time. Descriptive evidence from video footage, with videos included in the manuscript, showed that the tagged turtles spent 86% of their time in shallow water (<1.5 m) at a provisioning site. All individuals observed, both tagged and untagged, actively approached people and boats, with up to 10 turtles recorded feeding on squid offered by tourists at one time. During these feeding events, multiple accounts of atypical aggressive behaviour such as biting and ramming conspecifics were recorded. Furthermore, a review of online sources revealed the widespread significance of turtle feeding as a tourist activity in at least 20 locations within the global range of green sea turtles, as well as five locations with regular provisioning of either loggerhead (Caretta Caretta) or hawksbill (Eretmochelys imbracata) turtles. At the majority of the locations, turtles were fed animal matter such as fish scraps and squid. Although sample size limited quantitative analyses, we found indications of relatively high growth rates of two tagged turtles and low seagrass intake rates of all five tagged turtles. Therefore, our results emphasize the need to further investigate the impacts of turtle provisioning on natural foraging behaviour, ecosystem functioning as well as turtle growth rates and health implications. Supplemental feeding may increase habituation and dependency of turtles on humans with risks for turtle conservation. The innovative use of animal-borne camera technology may provide novel insights to behavioural consequences of human-wildlife interactions that can aid in the management and conservation of rare or endangered species.