This project aims to rapidly eradicate and confine two newly detected, early-stage populations of this species, Mohelnice and Šoulet. The affected pond in Mohelnice will be completely filled out with soil. At the Šoulet site, the primary management measure involves stocking of predatory fish. Other project activities are monitoring, conduction of eDNA analyses and crayfish plague testing and raising of public awareness.

New findings at Šoulet

As part of the project, eDNA analyses were used alongside field monitoring to investigate the distribution of marbled crayfish at both sites and in nearby waters. At Mohelnice, monitoring and eDNA analyses did not detect marbled crayfish in neighbouring waterbodies, and the population remains confined to the known site. At Šoulet, however, monitoring confirmed reproduction of marbled crayfish and the eDNA analyses detected the species in two nearby waterbodies where it had not previously been recorded. Both new sites are used for fishing, suggesting that the crayfish may have been introduced accidentally with stocked fish or deliberately released. Crayfish plague testing was also conducted at both project sites and in neighbouring waterbodies. No crayfish plague was detected on both sites.

Practical measures at both sites

At Mohelnice, a temporary foil barrier was installed around the pond to prevent marbled crayfish from escaping and to check for the presence of protected amphibian species, which could then be safely relocated if necessary. Surveys found no amphibians or other protected species at the site, providing an important information for planning the next stage of eradication. Filling out of the pond is a priority for the next reporting period. At Šoulet, predatory fish were stocked in June as biological control. However, long-term monitoring is needed to assess the effectiveness of this measure. Following the discovery of the two additional occurrences, possible next steps include introducing more predatory fish and increasing trapping efforts.

Raising public awareness

Public engagement remains an important part of the project. A workshop held during this reporting period was considered successful and beneficial, and another workshop is planned for the second half of the project. Information boards were planned for Šoulet during the first project period, but their installation was delayed due to staff turnover. The task has since been taken over by another staff member, and the boards will be installed during the next project period to raise awareness of invasive crayfish species. As part of the project, 4,000 leaflets on marbled crayfish and other non-native crayfish species were printed to raise public awareness of their impacts and prevent their spread.

The project continues with the support of landowners, regional authorities and other stakeholders.The monitoring results, particularly the new findings near Šoulet, will help guide future management decisions and target further action where it is most needed.

The measures are implemented with the support of IUCN Save Our Species (SOS), co-funded by the European Union under the project  Rapid Eradication and Confination of Marbled Crayfish Populations in Moravia, Czech Republic.