Finding of hybrid African catfish Clariobranchus in the River Danube

The record is confirmed of a Clariobranchus hybrid Clarias gariepinus x Heterobranchus sp. specimen in the River Danube in Croatia. Clarias gariepinus was introduced to Europe for farming and research purposes. Because of their faster growth and short time to achieve market size, Clariobranchus hybrids have gained attention in European aquaculture. To date, no record has been found in the literature of Clariobranchus hybrid escapees in inland waters of Europe. The present finding suggests that the Clariobranchus hybrid escaped from an unprotected aquaculture system or open pond farm. The threat of establishment of a population of this hybrid in suitable environments, such as thermal ponds, cannot be ruled out.

Automated summary

A hybrid Clariobranchus, a cross between Clarias gariepinus and Heterobranchus sp., has been found in the River Danube in Croatia. This hybrid fish has gained attention in European aquaculture due to its fast growth and short time to reach market size. The record of this hybrid fish escaping into inland waters of Europe has not been found in the literature. This finding suggests that the hybrid fish may have escaped from an unprotected aquaculture system or open pond farm and there is a potential threat of its establishment in suitable environments.