Mechanistic modelling for ecotoxicology and ecology

DEBtox Researc

Welcome to DEBtox Research

DEBtox Research is the private company that I (Tjalling Jager) operate since January 2015 to offer my knowledge and expertise on mechanistic modelling to customers. My mission is to strengthen the scientific foundation of ecotoxicology, environmental risk assessment, and life-history ecology, by the application of mechanistic models. Mechanistic modelling attempts to provide a (simplistic) explanation for the observed behaviour of the organism, rather than just describing it. Thereby, we gain a deeper understanding of the organism and the stressors affecting it. In turn, this understanding can help us to make educated extrapolations to untested situations. This is where fundamental research meets application!

My specialty is in the development and application of toxicokinetic and toxicodynamic models (at the level of the individual), in particular, models based on Dynamic Energy Budget (DEB) theory (more specifically: DEBkiss and DEBtox) and the General Unified Threshold model for Survival (GUTS). These models can be applied to a wide range of species (basically: all), and an enormous range of fundamental and applied research questions. More information on the type of activities that I have to offer can be found on the activities page.

I also maintain the sites and which contain much more detailed information about these models, as well as links to free e-books, software, and lists of relevant publications. This website is dedicated to my project activities.


  • 10 December 2019: version 1.0 of the standalone of openGUTS is available for download. See openGUTS download page. The software was developed in a Cefic-LRI funded project.
  • 9 May 2019: major update of the "Making sense of chemical stress" e-book. The book is now up-to-date with the streamlining of TKTD models that was started with GUTS. More information.
  • 8 Dec. 2018: An update to the GUTS e-book has been released. More information on the book.
  • 27 August 2018: the EFSA opinion on TKTD models is now available over here (open access). This opinion is a major step forward towards more routine application of GUTS and DEBtox in environmental risk assessment (in particular for pesticides).

DEBtox Research,, Chamber of Commerce Utrecht 62405055, email: tjalling (at)