Commercial harvest and export of snapping turtles (Chelydra serpentina) in the United States: trends and the efficacy of size limits at reducing harvest

Abstract

As Asian turtle populations have crashed, China has increasingly turned to international import to meet domestic demand, which has increased pressure on global turtle populations. Snapping turtles (Chelydra serpentina) are being harvested in unprecedented numbers in the United States (US) to meet the needs of this international market. Here we report US snapping turtle live export from 1999 to 2013, and for the first time test the effectiveness of size limits in reducing commercial harvest numbers. Over three million live snapping turtles from farm and wild caught stock were exported from the US to Asia in 2012–14 alone. Increases in the export of wild caught snapping turtles to over 200,000 individuals in 2012 and 2014, compared to under 50,000 in other years, may indicate that farms are becoming unable to keep up with increasing demand. Annual harvest pressure at the state level increased linearly from 1998 to 2013, mirroring trends in federal export over the same time period. Our model estimates that size-limits were effective at reducing harvest by 30–87% in years with high harvest pressure. However, the majority of size limit regulations result in the removal of larger breeding adults, which has been shown to be detrimental to long term population viability. Regulatory approaches dedicated to the long term management of this iconic species will need to balance the short term gains, in the form of reduced harvest rates, with long term population viability.