Eradication of American bullfrog in the Netherlands


Since 2009 an Early Warning System (EWS) for American bullfrog has been active in the southern part of the Netherlands to be able to detect bullfrogs, coming from the Belgian populations, in an early stage. In 2010 a population of the species was discovered by a citizen, who was informed by our online documentation. After a thorough inventory, eradication started in 2011 in close co operation with advice consultancy Natuurbalans – Limes Divergens. Two different methods were used in the two reproduction ponds:

  • Enclosure of the pond, as well as complete draining and removal of vegetation, mud and bullfrogs.
  • Enclosure of the pond and the use of dip nets, seines and fykes.

RAVON followed the sites using environmental DNA and we expect to declare the bullfrog population as eradicated in 2015. Conducting risk assessments, developing EWS’s and effective communication strategies, turned out to be crucial and specialized volunteers as well as the general public are extremely valuable in EWS’s.

In this project RAVON was involved in the EWS, communication with authorities, the general public and landowners, the actual execution of the necessary management and inventories and monitoring.

More information: Jeroen van Delft (

  RAVON is de kennisorganisatie voor reptielen, amfibieën en vissen. Advies, onderzoek & bescherming.   Telefoon: 024-7410600
Adres: zie contact pagina