South Bohemian scientists are deploying custom-designed, gentle traps in ponds and pools across the Vysočina region and the Třeboň Basin to curb invasive fish species threatening protected amphibians. Researchers aim to reduce invasive populations by at least ninety percent per locality, protecting native aquatic biodiversity from predatory species.
Freshwater ecosystems in the Czech Republic face a biological threat as non-native fish populations expand from commercial fishponds into vulnerable natural pools. Regional researchers are actively working to limit invasive fish species in water bodies across the Vysočina region and the Třeboň Basin. Species such as the weatherfish, silver Prussian carp, pumpkinseed sunfish, and brown bullhead actively decimate protected amphibian populations across multiple fragile habitats.
Engineering Gentle Traps for Precision Removal
To address the ecological imbalance without harming native fauna, hydrobiologists developed specialized equipment. Field researchers deploy cylindrical and star-shaped funnel traps designed with openings that allow the fish to enter inside, but gradually narrow to prevent escapes.
The operational mechanics of these devices require precise field management. Describing the capture apparatus in the field reporting from regional coverage, hydrobiologist Viktorie Váchová from the Biology Centre of the Academy of Sciences detailed the extraction process: We take them out into a bucket. We also have a cylindrical trap here, and then a star-shaped one. Around them are such openings that allow the fish to enter inside, but they gradually narrow and thus the fish later have trouble escaping.
Once captured, specimens are transferred to a designated station for biometric analysis. Researchers record measurements and weights before logging data. Over a two-year monitoring span across more than ten distinct sites, field teams successfully extracted approximately 100 kilograms of invasive fish.
Protecting Endangered Amphibians from Voracious Predators
The geographic character of the Třeboň landscape presents unique conservation challenges. Hydrobiologist Marek Šmejkal notes that while the region features many natural pools, adjacent commercial fishponds act as reservoirs that distribute invasive species into these sensitive wetland ecosystems.
The ecological stakes involve several amphibian species native to the targeted pools. Surveys in monitored waters confirmed populations of the smooth newt, alpine newt, and the moor frog. Larvae and tadpoles of these amphibians serve as prey for the brown bullhead, a predator known to consume adult newts as well.
Researchers observe that targeted species adapt differently to capture methods, requiring continuous refinement of trap designs, deployment durations, and bait selection. The conservation benchmark for each visited site targets at least a ninety percent reduction in total invasive fish numbers.
Measurable Habitat Recovery and Future Expansion
Targeted removal operations already yield ecological recoveries in treated water bodies. At one Vysočina location, the yellow-bellied toad returned in larger numbers following conservation intervention. Subsequent efforts at another site completely eradicated the Prussian carp, securing a defense for the native crucian carp population.
Building on these localized successes, scientific teams plan to scale their methodology. Field trials will expand into the Plzeň and Hradec Králové regions, testing whether these specialized aquatic management protocols can secure amphibian habitats across broader Czech territories.
