Winter fish kill. How to prevent it?

Winter fish kills are observed as a result of both a complete cessation of oxygen supply from the air and a sharp restriction of plant life under the ice. The formation of a stable ice cover and the impossibility of water-air contact is the main factor that can cause fish kills.

Winter fish kills in any given water body do not occur everywhere, but in separate areas, the size of which varies from year to year. Depending on the duration and stability of the ice cover, the water volume, and the fish stocking density, in some winters fish die completely, while in others only those individuals most sensitive to oxygen deficiency perish. Sharp fluctuations in water level can cause significant harm to overwintering fish, resulting in fish being crushed by ice in the coastal zone of the water body, leading to their death.

The first signs of winter fish kills are the appearance of young fish in ice holes and openings. The water at this time acquires an unpleasant odour and becomes cloudy.

In accordance with the Law of the Republic of Belarus "On Wildlife", state bodies, other organisations, and citizens are obliged to take measures to protect wild animals and fish found in emergency situations.

The lessees and users of fishing grounds (in leased or gratuitously used fishing grounds), and local executive and administrative bodies (in reserve fishing grounds) are responsible for organising and carrying out measures to prevent fish kill phenomena in accordance with the Rules for managing fishing and fishing.

Amateur anglers who visit water bodies should also not remain indifferent. They can help overwintering fish by making ice holes, thereby "introducing" additional oxygen into the water.

What measures should be taken to prevent mass fish deaths during the winter period?

Firstly, timely creation of ice holes on water bodies. Their number depends on the area of the water body and averages 3-5 per

one hectare. Ice holes are made both in the center of the water body and along its perimeter, where the depth of the unfrozen layer is 50-60 cm. To prevent freezing of ice holes, it is necessary to install sheaves of reeds, cattails, and other hollow "breathing" plants in them and hang bags of salt.

Secondly, apply lime to water bodies. Liming promotes the decomposition and acceleration of the mineralization of organic matter, as well as improves the gas regime and neutralizes the acidic reaction of water. Unslaked lime is applied at a rate of 1-2 centners per hectare; when using slaked lime or ground limestone, the application rates increase by 1.3 and 1.8 times, respectively.

Thirdly, hang bags of salt in such ice holes at a rate of 5 kg per bag. Technical salt, which is used for cleaning boilers in boiler rooms, can also be recommended as salt.

The Lepel Interdistrict Inspectorate for the Protection of Fauna and Flora requests everyone who visits water bodies, at the first signs of winter fish kill, to report to the Lepel Interdistrict Inspectorate for the Protection of Fauna and Flora by **phone 8 (02132) 3-43-85, 8(029)291-42-55** or to take the above measures independently to save the fish.