Eurasian otter

The Eurasian otter (Lutra lutra) belongs to the order Carnivora and the family Mustelidae. While it is an iconic mammal in natural habitats, in the agricultural sector, specifically in commercial fish farming, it acts as a significant pest that can severely threaten the productivity and financial viability of aquaculture facilities.

The primary concern for fish farmers is the otter's diet, which consists mainly of fish. These predators are capable of raiding pond systems, hatcheries, and commercial fish farms with high efficiency. They are especially destructive when they target high-value species, causing substantial losses to biomass and potential harvest revenue.

Regarding its biology, the otter is a highly adaptive and solitary predator. It possesses a high metabolic rate, requiring it to hunt frequently. Its ability to travel long distances across land between water bodies allows it to infiltrate even isolated fish farming sites that appear secure, often establishing a permanent presence near abundant food sources.

The damage caused by the Eurasian otter is dual in nature. Firstly, there is the direct loss of livestock through consumption. Secondly, the otter often inflicts severe non-lethal injuries on remaining fish, which causes secondary infections and stress in the population. This behavior can result in mass mortality events within a farm, far exceeding the actual amount of fish consumed.

Protecting fish farms from the Eurasian otter requires a multi-layered approach to pest management. Recommended practices include:

• Installing high-quality fencing with subterranean netting to prevent burrowing.
• Utilizing electric fencing specifically designed for small semi-aquatic mammals.
• Implementing automated visual and acoustic deterrents to minimize hunting success.
• Managing the perimeter by clearing dense vegetation to reduce cover for approaching predators.