Kategorie: News
Successfully Managing Invasive Species Through Knowledge and Collaboration
The aquatil symposium “Bullfrog – Monitoring & Management Strategies” brings together experts from academia, conservation, government agencies, and the field with dedicated citizens, nature observers, recreational divers, and other interested parties.
Date: July 16, 2026
Time: 10:00 a.m.–5:30 p.m.
Online & free of charge (Reg.Link)
Participants can expect exciting insights into:
- The biology and ecology of the bullfrog
- Modern monitoring methods such as environmental DNA (eDNA)
- Field reports from Germany, Belgium, France, and the USA
- Management and control strategies
- Citizen science projects and the active role of recreational divers in species conservation
The event focuses on current information, practical experiences, and opportunities for discussion regarding invasive species, water protection, and the conservation of biodiversity.
The Bullfrog
The American bullfrog (Lithobates catesbeianus) is an invasive species capable of causing significant ecological damage worldwide. It is listed on the EU Union List of Invasive Species and is classified as particularly problematic due to its dispersal capacity and ecological consequences; it has been documented in approximately 40 countries worldwide. In Baden-Württemberg, its known distribution is currently limited to a contiguous area in the northern Upper Rhine region.
Particularly dangerous are the massive tadpoles, which can grow up to 18 centimeters in size: they alter food chains and habitats, threatening native amphibians, large insects (such as dragonflies and beetles), mollusks, as well as birds, small mammals, and reptiles. Because there are numerous lakes and ponds in the area, there is a risk of further spread into neighboring bodies of water.
Since around 2012, researchers have been documenting observations during scientific dives—photos and videos show year-round activity. To better understand the tadpoles’ migration and overwintering behavior, telemetry studies were conducted: Radio transmitters were non-invasively attached to tadpoles, enabling the first-ever detection of targeted migration behavior toward underwater overwintering sites.
Studies show that bullfrog larvae do indeed overwinter and can suspend metamorphosis during this period; skeletochronological findings confirmed growth rings indicative of overwintering. In addition, data on a key identifying characteristic—the mouth region of the tadpoles—vary, which is why the entire body morphology must be used for reliable species identification.
Various measures have already been tested to contain the population: the removal of adult animals, the coordinated and authorized capture of tadpoles by recreational divers, and other practical measures. Species detection dogs are also being tested for the targeted search for adult frogs—an approach that has proven successful at other sites and is now being tested here. The goal is to develop practical tools for limiting the spread based on ecological research.
The project “Bullfrog Control in Baden-Württemberg” is funded by the Baden-Württemberg Nature Conservation Fund (from proceeds of the Glücksspirale lottery); the work is additionally supported by foundations, among others. For those interested, the eBooklet “Bullfrog Knowledge” is available as a practical information source, free of charge as a PDF.
Further information and registration:
Information: https://aquatil.org/Ochsenfrosch-Fachtagung
Registration: https://eveeno.com/310895990
See also: Frehswater Adventure