Population assessment and impact of trade on the Asian Water Dragon (Physignathus cocincinus Cuvier, 1829) in Vietnam

Abstract

Physignathus cocincinus has been harvested in Vietnam for the local food market as well as for the international pet trade since at least 20 years. However, comprehensive knowledge about its global conservation status is lacking so far. Our study was conducted to evaluate potential impacts of harvest and trade on wild populations by providing an overview of the international and domestic trade in P. cocincinus in Vietnam. To assess the level of anthropogenic impacts on wild populations, we compared population densities and sizes of an undisturbed and several disturbed sites in northern Vietnam between 2014 and 2016 by using a mark-recapture method. The results indicate that mean densities are smaller in disturbed populations than in the reference population. Imports of 1.47 million individuals, mainly of wild origin from Vietnam, into the EU and US were documented in the last 20 years. Regarding national pet trade, a total of 51 domestic dealers and nine online pet shops trading P. cocincinus were documented in Vietnam since 2015. Our study also highlights a considerable harvest for the national use, viz. pet trade and food consumption, in Asian range states. We assume that the long-term viability of P. cocincinus in the Indo-China region, at least in the North of Vietnam, is at risk due to the considerable extent of harvest and ongoing habitat degradation. Thus, we suggest stringent conservation measures to protect wild populations more efficiently and improve habitat conservation.

Keywords

• Population assessment
• Mark-recapture method
• Trade
• Conservation
• Vietnam