Wels catfish

The Wels catfish (Silurus glanis) belongs to the order Siluriformes and the family Siluridae. As a massive freshwater predator, it acts as a disruptive biological agent in managed agricultural ecosystems, particularly in integrated rice-fish farming systems where its presence can cause significant economic losses.

In an agricultural context, this species is considered a pest because it threatens the survival of cultivated fish species, such as carp, which are intentionally introduced into rice paddies to serve as biocontrol agents against pests and weeds. The catfish acts as a top-tier predator that consumes these beneficial species.

The biological cycle begins with spawning in late spring, usually in shallow waters. During irrigation cycles in rice paddies, the catfish can enter the system through inflow channels. Once inside, they reproduce rapidly, and the aggressive young quickly strip the environment of the beneficial fish populations required for sustainable rice cultivation.

The damage profile includes both ecological disruption and physical destruction of agricultural infrastructure. The catfish’s burrowing behavior can compromise the integrity of earthen dikes and levees within irrigation networks. This leads to water loss, which is critical for maintaining the specific hydrostatic environment required for optimal rice yield.

Control measures primarily focus on exclusion and physical removal. Farmers should install fine-mesh filters at all water intake points to prevent larvae and adult catfish from entering the irrigation system. Periodic drainage of ponds and checking of secondary canals, combined with selective fishing using specialized traps, remain the standard practice to keep populations under control.