Great bittern

The great bittern (Botaurus stellaris) is a member of the Ardeidae family. While often protected as wildlife, in the context of commercial aquaculture, it is categorized as a pest species due to its habit of predating on valuable fish stocks in intensive farming systems.

The affected crops—or rather, aquatic biological assets—include farmed carp, trout, and other juvenile fish stocks raised in shallow ponds. Because these ponds often contain high concentrations of young fish, they become primary hunting grounds for the bittern, leading to significant economic losses.

The biology of the species is centered around reed beds. The breeding season demands high energy intake for the parents to feed their chicks, which correlates with the period when fish farmers are most vulnerable. This peak activity often coincides with the stocking of ponds with young fish.

The damage caused is direct mortality of the stock. Bitterns are stealth hunters, making them difficult to monitor. Their ability to remain camouflaged in vegetation allows them to feed consistently on fish without being detected by farm management, often leading to underestimated losses.

Protection measures should be multifaceted. Using overhead netting is the most reliable way to prevent access to small ponds. Additionally, the maintenance of clear banks by removing dense reed vegetation reduces the nesting and ambush potential of the habitat, encouraging the birds to relocate elsewhere.