Biological Invasions

, Volume 14, Issue 12, pp 2657–2664 | Cite as

Online trading tools as a method of estimating propagule pressure via the pet-release pathway

  • K. Heidy KikillusEmail author
  • K. M. Hare
  • S. Hartley
Original Paper


The increasing amount of internet trade in live animals has facilitated the sale and circulation of exotic species all over the world. This is an area of concern, as the deliberate or accidental release of pets is an important pathway by which exotic species are often introduced into new environments, often with negative effects on the local species and ecosystems. Internet trading sites were used to determine the distribution and magnitude of propagule pressure of red-eared slider turtles (RES; Trachemys scripta elegans) within the New Zealand pet trade. Sites were tracked daily from October 1, 2007 to September 30, 2009 and information on age, sex, season, and location was recorded. More than 1,500 sales and 80 reports of lost/found RES were recorded. Unsurprisingly, the highest number of sales and lost/found RES was in Auckland, the region with the highest human population. Females were more often reported as lost or found than males, despite a similar sex ratio of sales. The type and quality of information gathered in this manner is not perfect, as it only provides an estimate of minimum numbers of animals that are being traded/lost into the environment, but nonetheless, provides useful data when planning a management or eradication plan for feral turtles in New Zealand. Of concern, our results highlighted areas where turtles were most often being released in New Zealand, being those areas predicted to be the most climatically-suitable for this species, and in which incubation conditions were most likely to be met. Monitoring online sales of exotic species provides useful demographic information, as well as an indication of propagule pressure via the pet-release pathway. This technique is applicable to other species and may be a useful tool to help determine locations at risk of the establishment of other exotic species.


Invasive species Reptiles Red-eared slider turtles Trachemys scripta elegans New Zealand Pet trade 



Red-eared slider turtle (Trachemys scripta elegans)



Funding was provided to KHK by a Victoria University of Wellington PhD Scholarship. We thank the Victoria University of Wellington Bug Club, Herpetological Hatchet Group, and two anonymous reviewers for comments to improve this manuscript.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  1. 1.Centre for Biodiversity and Restoration Ecology, School of Biological SciencesVictoria University of WellingtonWellingtonNew Zealand

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