Water shrew

The water shrew (genus Neomys) is a small mammal belonging to the family Soricidae, order Eulipotyphla. While generally recognized for their role in insect control in nature, they can act as problematic pests in specific agricultural settings, particularly in aquaculture and private fishery management.

The primary damage caused by these mammals occurs in fish nurseries and hatcheries. Water shrews are voracious predators that feed on fish fry and eggs, leading to substantial losses in fish production. They can also cause structural damage to pond embankments and dikes by burrowing extensively within the banks.

The biology of the water shrew is centered around aquatic environments. They are semi-aquatic, highly skilled swimmers capable of remaining active throughout the year. Their reproductive capacity is relatively high, with females producing multiple litters annually, which allows their populations to recover quickly if environmental conditions are favorable.

The damage potential is exacerbated by their predatory behavior. Unlike typical rodents, water shrews possess toxic saliva that paralyzes their prey, allowing them to hunt organisms significantly larger than themselves. In high-density fish farming environments, this predation behavior can lead to significant drops in stock levels and operational efficiency.

Effective protection measures focus on habitat modification and physical exclusion. To protect fish stocks, pond managers should use fine-mesh fencing around nursery tanks. Additionally, clearing excessive vegetation around the banks and reinforcing slopes with stone or geotextiles can discourage burrowing. In critical cases, integrated pest management practices are employed to monitor and limit population numbers.